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1.  The impact of the metabotropic glutamate receptor and other gene family interaction networks on autism 
Nature Communications  2014;5:4074.
Although multiple reports show that defective genetic networks underlie the aetiology of autism, few have translated into pharmacotherapeutic opportunities. Since drugs compete with endogenous small molecules for protein binding, many successful drugs target large gene families with multiple drug binding sites. Here we search for defective gene family interaction networks (GFINs) in 6,742 patients with the ASDs relative to 12,544 neurologically normal controls, to find potentially druggable genetic targets. We find significant enrichment of structural defects (P≤2.40E−09, 1.8-fold enrichment) in the metabotropic glutamate receptor (GRM) GFIN, previously observed to impact attention deficit hyperactivity disorder (ADHD) and schizophrenia. Also, the MXD-MYC-MAX network of genes, previously implicated in cancer, is significantly enriched (P≤3.83E−23, 2.5-fold enrichment), as is the calmodulin 1 (CALM1) gene interaction network (P≤4.16E−04, 14.4-fold enrichment), which regulates voltage-independent calcium-activated action potentials at the neuronal synapse. We find that multiple defective gene family interactions underlie autism, presenting new translational opportunities to explore for therapeutic interventions.
The autism spectrum disorders are complex genetic traits characterized by various neurodevelopmental deficits. Here, the authors analyse defective gene family interaction networks in autism cases and healthy controls and identify potential gene family interactions that may contribute to autism aetiology.
doi:10.1038/ncomms5074
PMCID: PMC4059929  PMID: 24927284
2.  Genome-Wide Association Study of Maternal and Inherited Loci for Conotruncal Heart Defects 
PLoS ONE  2014;9(5):e96057.
Conotruncal and related heart defects (CTDs) are a group of serious and relatively common birth defects. Although both maternal and inherited genotypes are thought to play a role in the etiology of CTDs, few specific genetic risk factors have been identified. To determine whether common variants acting through the genotype of the mother (e.g. via an in utero effect) or the case are associated with CTDs, we conducted a genome-wide association study of 750 CTD case-parent triads, with follow-up analyses in 358 independent triads. Log-linear analyses were used to assess the association of CTDs with the genotypes of both the mother and case. No association achieved genomewide significance in either the discovery or combined (discovery+follow-up) samples. However, three loci with p-values suggestive of association (p<10−5) in the discovery sample had p-values <0.05 in the follow-up sample and p-values in the combined data that were lower than in the discovery sample. These included suggestive association with an inherited intergenic variant at 20p12.3 (rs6140038, combined p = 1.0×10−5) and an inherited intronic variant in KCNJ4 at 22q13.1 (rs2267386, combined p = 9.8×10−6), as well as with a maternal variant in SLC22A24 at 11q12.3 (rs11231379, combined p = 4.2×10−6). These observations suggest novel candidate loci for CTDs, including loci that appear to be associated with the risk of CTDs via the maternal genotype, but further studies are needed to confirm these associations.
doi:10.1371/journal.pone.0096057
PMCID: PMC4011736  PMID: 24800985
3.  Evidence From Human and Zebrafish That GPC1 Is a Biliary Atresia Susceptibility Gene 
Gastroenterology  2013;144(5):1107-1115.e3.
BACKGROUND & AIMS
Biliary atresia (BA) is a progressive fibroinflammatory disorder of infants involving the extrahepatic and intrahepatic biliary tree. Its etiology is unclear but is believed to involve exposure of a genetically susceptible individual to certain environmental factors. BA occurs exclusively in the neonatal liver, so variants of genes expressed during hepatobiliary development could affect susceptibility. Genome-wide association studies previously identified a potential region of interest at 2q37. We continued these studies to narrow the region and identify BA susceptibility genes.
METHODS
We searched for copy number variants that were increased among patients with BA (n = 61) compared with healthy individuals (controls; n = 5088). After identifying a candidate gene, we investigated expression patterns of orthologues in zebrafish liver and the effects of reducing expression, with morpholino antisense oligonucleotides, on biliary development, gene expression, and signal transduction.
RESULTS
We observed a statistically significant increase in deletions at 2q37.3 in patients with BA that resulted in deletion of one copy of GPC1, which encodes glypican 1, a heparan sulfate proteoglycan that regulates Hedgehog signaling and inflammation. Knockdown of gpc1 in zebrafish led to developmental biliary defects. Exposure of the gpc1 morphants to cyclopamine, a Hedgehog antagonist, partially rescued the gpc1-knockdown phenotype. Injection of zebrafish with recombinant Sonic Hedgehog led to biliary defects similar to those of the gpc1 morphants. Liver samples from patients with BA had reduced levels of apical GPC1 in cholangiocytes compared with samples from controls.
CONCLUSIONS
Based on genetic analysis of patients with BA and zebrafish, GPC1 appears to be a BA susceptibility gene. These findings also support a role for Hedgehog signaling in the pathogenesis of BA.
doi:10.1053/j.gastro.2013.01.022
PMCID: PMC3736559  PMID: 23336978
GWA; Susceptibility Loci; Animal Model; Bile Duct Growth and Development
4.  GWAS of blood cell traits identifies novel associated loci and epistatic interactions in Caucasian and African-American children 
Human Molecular Genetics  2012;22(7):1457-1464.
Hematological traits are important clinical indicators, the genetic determinants of which have not been fully investigated. Common measures of hematological traits include red blood cell (RBC) count, hemoglobin concentration (HGB), hematocrit (HCT), mean corpuscular hemoglobin (MCH), MCH concentration (MCHC), mean corpuscular volume (MCV), platelet count (PLT) and white blood cell (WBC) count. We carried out a genome-wide association study of the eight common hematological traits among 7943 African-American children and 6234 Caucasian children. In African Americans, we report five novel associations of HBE1 variants with HCT and MCHC, the alpha-globin gene cluster variants with RBC and MCHC, and a variant at the ARHGEF3 locus with PLT, as well as replication of four previously reported loci at genome-wide significance. In Caucasians, we report a novel association of variants at the COPZ1 locus with PLT as well as replication of four previously reported loci at genome-wide significance. Extended analysis of an association observed between MCH and the alpha-globin gene cluster variants demonstrated independent effects and epistatic interaction at the locus, impacting the risk of iron deficiency anemia in African Americans with specific genotype states. In summary, we extend the understanding of genetic variants underlying hematological traits based on analyses in African-American children.
doi:10.1093/hmg/dds534
PMCID: PMC3657475  PMID: 23263863
5.  Copy number variation analysis in the context of electronic medical records and large-scale genomics consortium efforts 
The goal of this paper is to review recent research on copy number variations (CNVs) and their association with complex and rare diseases. In the latter part of this paper, we focus on how large biorepositories such as the electronic medical record and genomics (eMERGE) consortium may be best leveraged to systematically mine for potentially pathogenic CNVs, and we end with a discussion of how such variants might be reported back for inclusion in electronic medical records as part of medical history.
doi:10.3389/fgene.2014.00051
PMCID: PMC3957100  PMID: 24672537
CNV; copy number; structural variation; eMERGE; review
6.  A genome wide association study of plasma uric acid levels in obese cases and never-overweight controls 
Obesity (Silver Spring, Md.)  2013;21(9):E490-E494.
Objective
To identify plasma uric acid related genes in extremely obese and normal weight individuals using genome wide association studies (GWAS).
Design and Methods
Using genotypes from a GWAS focusing on obesity and thinness, we performed quantitative trait association analyses (PLINK) for plasma uric acid levels in 1,060 extremely obese individuals [body mass index (BMI) >35 kg/m2] and normal-weight controls (BMI<25kg/m2). In 961 samples with uric acid data, 924 were females.
Results
Significant associations were found in SLC2A9 gene SNPs and plasma uric acid levels (rs6449213, P=3.15×10−12). DIP2C gene SNP rs877282 also reached genome wide significance(P=4,56×10−8). Weaker associations (P<1×10−5) were found in F5, PXDNL, FRAS1, LCORL, and MICAL2genes. Besides SLC2A9, 3 previously identified uric acid related genes ABCG2 (rs2622605, P=0.0026), SLC17A1 (rs3799344, P=0.0017), and RREB1 (rs1615495, P =0.00055) received marginal support in our study.
Conclusions
Two genes/chromosome regions reached genome wide association significance (P< 1× 10−7, 550K SNPs) in our GWAS : SLC2A9, the chromosome 2 60.1 Mb region (rs6723995), and the DIP2C gene region. Five other genes (F5, PXDNL, FRAS1, LCORL, and MICAL2) yielded P<1× 10−5. Four previous reported associations were replicated in our study, including SLC2A9, ABCG2, RREB, and SLC17A1.
doi:10.1002/oby.20303
PMCID: PMC3762924  PMID: 23703922
uric acid; genome wide association study; obesity
7.  De novo mutations in histone modifying genes in congenital heart disease 
Nature  2013;498(7453):220-223.
Congenital heart disease (CHD) is the most frequent birth defect, affecting 0.8% of live births1. Many cases occur sporadically and impair reproductive fitness, suggesting a role for de novo mutations. By analysis of exome sequencing of parent-offspring trios, we compared the incidence of de novo mutations in 362 severe CHD cases and 264 controls. CHD cases showed a significant excess of protein-altering de novo mutations in genes expressed in the developing heart, with an odds ratio of 7.5 for damaging mutations. Similar odds ratios were seen across major classes of severe CHD. We found a marked excess of de novo mutations in genes involved in production, removal or reading of H3K4 methylation (H3K4me), or ubiquitination of H2BK120, which is required for H3K4 methylation2–4. There were also two de novo mutations in SMAD2; SMAD2 signaling in the embryonic left-right organizer induces demethylation of H3K27me5. H3K4me and H3K27me mark `poised' promoters and enhancers that regulate expression of key developmental genes6. These findings implicate de novo point mutations in several hundred genes that collectively contribute to ~10% of severe CHD.
doi:10.1038/nature12141
PMCID: PMC3706629  PMID: 23665959
8.  GWAS meta analysis identifies TSNARE1 as a novel Schizophrenia / Bipolar susceptibility locus 
Scientific Reports  2013;3:3075.
We carried out a GWAS meta-analysis of combined mixed-ancestry schizophrenia, schizoaffective, and bipolar cohorts that resulted in the identification of six genome-wide significant loci, including one novel locus at chr8q24.3, encompassing TSNARE1 (P = 1.28 × 10−9). The analysis included a total of 13,394 cases and 34,676 controls. While the function of TSNARE1 remains unknown, bioinformatic predictions based on phylogenetic ancestry indicate it may have a vertebrate-specific function in intracellular protein transport and synaptic vesicle exocytosis.
doi:10.1038/srep03075
PMCID: PMC3810676  PMID: 24166486
9.  Both Rare and De Novo Copy Number Variants Are Prevalent in Agenesis of the Corpus Callosum but Not in Cerebellar Hypoplasia or Polymicrogyria 
PLoS Genetics  2013;9(10):e1003823.
Agenesis of the corpus callosum (ACC), cerebellar hypoplasia (CBLH), and polymicrogyria (PMG) are severe congenital brain malformations with largely undiscovered causes. We conducted a large-scale chromosomal copy number variation (CNV) discovery effort in 255 ACC, 220 CBLH, and 147 PMG patients, and 2,349 controls. Compared to controls, significantly more ACC, but unexpectedly not CBLH or PMG patients, had rare genic CNVs over one megabase (p = 1.48×10−3; odds ratio [OR] = 3.19; 95% confidence interval [CI] = 1.89–5.39). Rare genic CNVs were those that impacted at least one gene in less than 1% of the combined population of patients and controls. Compared to controls, significantly more ACC but not CBLH or PMG patients had rare CNVs impacting over 20 genes (p = 0.01; OR = 2.95; 95% CI = 1.69–5.18). Independent qPCR confirmation showed that 9.4% of ACC patients had de novo CNVs. These, in comparison to inherited CNVs, preferentially overlapped de novo CNVs previously observed in patients with autism spectrum disorders (p = 3.06×10−4; OR = 7.55; 95% CI = 2.40–23.72). Interestingly, numerous reports have shown a reduced corpus callosum area in autistic patients, and diminished social and executive function in many ACC patients. We also confirmed and refined previously known CNVs, including significantly narrowing the 8p23.1-p11.1 duplication present in 2% of our current ACC cohort. We found six novel CNVs, each in a single patient, that are likely deleterious: deletions of 1p31.3-p31.1, 1q31.2-q31.3, 5q23.1, and 15q11.2-q13.1; and duplications of 2q11.2-q13 and 11p14.3-p14.2. One ACC patient with microcephaly had a paternally inherited deletion of 16p13.11 that included NDE1. Exome sequencing identified a recessive maternally inherited nonsense mutation in the non-deleted allele of NDE1, revealing the complexity of ACC genetics. This is the first systematic study of CNVs in congenital brain malformations, and shows a much higher prevalence of large gene-rich CNVs in ACC than in CBLH and PMG.
Author Summary
Here, we systematically test the genetic etiology of three common developmental brain malformations: agenesis of the corpus callosum (ACC), cerebellar hypoplasia (CBLH), and polymicrogyria (PMG) by copy number variation (CNV) analysis in a large cohort of brain malformation patients and controls. We found significantly more ACC but not CBLH or PMG patients with rare genic CNVs over one megabase and with rare CNVs impacting over 20 genes when compared with controls. De novo CNVs were found in 9.4% of ACC patients, and interestingly many such CNVs overlapped with de novo CNVs observed in autism. Notably, numerous studies have demonstrated a reduction in the corpus callosum area in autistic brains. Our analysis also refined previously known large CNVs that cause these malformations, and identified six novel CNVs that are likely deleterious. One ACC patient had inherited a deletion from the father which, through exome sequencing, was found to uncover a recessive nonsense mutation in NDE1 on the non-deleted allele inherited from the mother. Our study is the first to systematically evaluate the burden of rare genic CNVs in congenital brain malformations and shows that large gene-rich CNVs are more common in ACC than in CBLH and PMG.
doi:10.1371/journal.pgen.1003823
PMCID: PMC3789824  PMID: 24098143
10.  Common variation contributes to the genetic architecture of social communication traits 
Molecular Autism  2013;4:34.
Background
Social communication difficulties represent an autistic trait that is highly heritable and persistent during the course of development. However, little is known about the underlying genetic architecture of this phenotype.
Methods
We performed a genome-wide association study on parent-reported social communication problems using items of the children’s communication checklist (age 10 to 11 years) studying single and/or joint marker effects. Analyses were conducted in a large UK population-based birth cohort (Avon Longitudinal Study of Parents and their Children, ALSPAC, N = 5,584) and followed-up within a sample of children with comparable measures from Western Australia (RAINE, N = 1364).
Results
Two of our seven independent top signals (P-discovery <1.0E-05) were replicated (0.009
Single-variant findings were complemented by estimations of the narrow-sense heritability in ALSPAC suggesting that approximately a fifth of the phenotypic variance in social communication traits is accounted for by joint additive effects of genotyped single nucleotide polymorphisms throughout the genome (h2(SE) = 0.18(0.066), P = 0.0027).
Conclusion
Overall, our study provides both joint and single-SNP-based evidence for the contribution of common polymorphisms to variation in social communication phenotypes.
doi:10.1186/2040-2392-4-34
PMCID: PMC3853437  PMID: 24047820
ALSPAC; RAINE; Autistic trait; GWAS; Social communication; Association
Nature genetics  2010;42(4):289-291.
Eosinophilic esophagitis (EoE) is a polygenic disorder characterized by the accumulation of eosinophils in the esophagus. We carried out a genome-wide association study on clinically and biopsy confirmed EoE patients to identify common variants associated with the disease risk. One hundred and eighty one EoE samples from Cincinnati Children’s Hospital (CCHMC) and 170 EoE samples and ~3100 controls from Children’s Hospital of Philadelphia (CHOP) were genotyped on the Illumina 550K BeadChip. All patients and controls were of European ancestry. Following standard quality control filtering of the genotype data we carried out Cochran-Armitage trend tests at each SNP using the CCHMC samples as a discovery cohort. We detected genome-wide association with variants on chr5q22 that mapped to a single LD block encompassing the TSLP and WDR36 genes. The most significantly associated SNP at that locus which maps upstream of the TSLP gene remained wide significant after Bonferroni correction (rs3806932, uncorrected P-value = 7.18×10−8, OR = 0.54). Eleven other SNPs in LD with rs3806932 were also significantly associated with EoE and mapped to the same LD block on 5q22. We subsequently replicated the association in the independent CHOP cohort (170 cases, 1130 controls) with rs3806932 P-value = 8×10−3 OR = 0.73; combined P-value for rs3806932 across CCHMC and CHOP cohorts = 3.19×10−9). In addition, TSLP was overexpressed in the esophagus of EoE patients compared with control individuals with no differences observed in the expression of WDR36. In conclusion, we have identified the first genetic association with EoE predisposition at 5q22 implicating TSLP and/or WDR36 as genes potentially involved in the pathogenesis of EoE.
doi:10.1038/ng.547
PMCID: PMC3740732  PMID: 20208534
Obesity (Silver Spring, Md.)  2013;21(1):159-163.
Common variation at the loci harboring FTO, MC4R and TMEM18 is consistently reported as being statistically the most strongly associated with obesity. We investigated if these loci also harbor rarer missense variants that confer substantially higher risk of common childhood obesity in African American (AA) children. We sequenced the exons of FTO, MC4R and TMEM18 in an initial subset of our cohort i.e. 200 obese (BMI≥95th percentile) and 200 lean AA children (BMI≤5th percentile). Any missense exonic variants that were uncovered went on to be further genotyped in a further 768 obese and 768 lean (BMI≤50th percentile) children of the same ethnicity. A number of exonic variants were observed from our sequencing effort: seven in FTO, of which four were non-synonymous (A163T, G182A, M400V and A405V), thirteen in MC4R, of which six were non-synonymous (V103I, N123S, S136A, F202L, N240S and I251L) and four in TMEM18, of which two were non-synonymous (P2S and V113L). Follow-up genotyping of these missense variants revealed only one significant difference in allele frequency between cases and controls, namely with N240S in MC4R(Fisher's Exact P = 0.0001). In summary, moderately rare missense variants within the FTO, MC4R and TMEM18 genes observed in our study did not confer risk of common childhood obesity in African Americans except for a degree of evidence for one known loss-of-function variant in MC4R.
doi:10.1002/oby.20147
PMCID: PMC3605748  PMID: 23505181
Obesity; Pediatrics; Genomics
Biological Psychiatry  2011;71(5):392-402.
Background
Studies of copy number variation (CNV) have successfully characterized loci and molecular pathways involved in a range of neuropsychiatric conditions. We conducted an analysis of rare CNVs in Tourette Syndrome (TS) to identify novel risk regions and relevant molecular pathways, evaluate the burden of structural variation in cases versus controls, and to assess the overlap of identified variations with those implicated in other neuropsychiatric syndromes.
Methods
We conducted a case-control study of 460 individuals with TS, including 148 parent-child trios and 1131 controls. CNV analysis was undertaken using 370K to 1M probe arrays, and genome-wide genotyping data was used to match cases and controls for ancestry. Transmitted and de novo CNVs present in < 1% of the population were evaluated.
Results
While there was no significant increase in the number of de novo or transmitted rare CNVs in cases versus controls, pathway analysis using multiple algorithms showed enrichment of genes within histamine receptor (H1R and H2R) signaling pathways (p=5.8×10-4-1.6×10-2) as well as “axon guidance”, “cell adhesion”, “nervous system development” and “synaptic structure and function” processes. Genes mapping within rare CNVs in TS showed significant overlap with those previously identified in autism spectrum disorders (ASD), but not intellectual disability or schizophrenia. Three large, likely-pathogenic, de novo events were identified, including one disrupting multiple gamma-Aminobutyric acid (GABA) receptor genes.
Conclusions
We identify further evidence supporting recent findings regarding the involvement of histaminergic and GABAergic mechanisms in the etiology of TS and show an overlap of rare CNVs in TS and ASD.
doi:10.1016/j.biopsych.2011.09.034
PMCID: PMC3282144  PMID: 22169095
Tourette syndrome; copy number variation; CNV; histamine; GABA; autism
PLoS ONE  2013;8(1):e53846.
Longevity has a strong genetic component evidenced by family-based studies. Lipoprotein metabolism, FOXO proteins, and insulin/IGF-1 signaling pathways in model systems have shown polygenic variations predisposing to shorter lifespan. To test the hypothesis that rare variants could influence lifespan, we compared the rates of CNVs in healthy children (0–18 years of age) with individuals 67 years or older. CNVs at a significantly higher frequency in the pediatric cohort were considered risk variants impacting lifespan, while those enriched in the geriatric cohort were considered longevity protective variants. We performed a whole-genome CNV analysis on 7,313 children and 2,701 adults of European ancestry genotyped with 302,108 SNP probes. Positive findings were evaluated in an independent cohort of 2,079 pediatric and 4,692 geriatric subjects. We detected 8 deletions and 10 duplications that were enriched in the pediatric group (P = 3.33×10−8–1.6×10−2 unadjusted), while only one duplication was enriched in the geriatric cohort (P = 6.3×10−4). Population stratification correction resulted in 5 deletions and 3 duplications remaining significant (P = 5.16×10−5–4.26×10−2) in the replication cohort. Three deletions and four duplications were significant combined (combined P = 3.7×10−4−3.9×10−2). All associated loci were experimentally validated using qPCR. Evaluation of these genes for pathway enrichment demonstrated ∼50% are involved in alternative splicing (P = 0.0077 Benjamini and Hochberg corrected). We conclude that genetic variations disrupting RNA splicing could have long-term biological effects impacting lifespan.
doi:10.1371/journal.pone.0053846
PMCID: PMC3559729  PMID: 23382853
Discovery medicine  2011;12(62):41-55.
Exome sequencing has identified the causes of several Mendelian diseases, although it has rarely been used in a clinical setting to diagnose the genetic cause of an idiopathic disorder in a single patient. We performed exome sequencing on a pedigree with several members affected with attention deficit/hyperactivity disorder (ADHD), in an effort to identify candidate variants predisposing to this complex disease. While we did identify some rare variants that might predispose to ADHD, we have not yet proven the causality for any of them. However, over the course of the study, one subject was discovered to have idiopathic hemolytic anemia (IHA), which was suspected to be genetic in origin. Analysis of this subject’s exome readily identified two rare non-synonymous mutations in PKLR gene as the most likely cause of the IHA, although these two mutations had not been documented before in a single individual. We further confirmed the deficiency by functional biochemical testing, consistent with a diagnosis of red blood cell pyruvate kinase deficiency. Our study implies that exome and genome sequencing will certainly reveal additional rare variation causative for even well-studied classical Mendelian diseases, while also revealing variants that might play a role in complex diseases. Furthermore, our study has clinical and ethical implications for exome and genome sequencing in a research setting; how to handle unrelated findings of clinical significance, in the context of originally planned complex disease research, remains a largely uncharted area for clinicians and researchers.
PMCID: PMC3544941  PMID: 21794208
Nucleic Acids Research  2013;41(5):e64.
A number of copy number variation (CNV) calling algorithms exist; however, comprehensive software tools for CNV association studies are lacking. We describe ParseCNV, unique software that takes CNV calls and creates probe-based statistics for CNV occurrence in both case–control design and in family based studies addressing both de novo and inheritance events, which are then summarized based on CNV regions (CNVRs). CNVRs are defined in a dynamic manner to allow for a complex CNV overlap while maintaining precise association region. Using this approach, we avoid failure to converge and non-monotonic curve fitting weaknesses of programs, such as CNVtools and CNVassoc, and although Plink is easy to use, it only provides combined CNV state probe-based statistics, not state-specific CNVRs. Existing CNV association methods do not provide any quality tracking information to filter confident associations, a key issue which is fully addressed by ParseCNV. In addition, uncertainty in CNV calls underlying CNV associations is evaluated to verify significant results, including CNV overlap profiles, genomic context, number of probes supporting the CNV and single-probe intensities. When optimal quality control parameters are followed using ParseCNV, 90% of CNVs validate by polymerase chain reaction, an often problematic stage because of inadequate significant association review. ParseCNV is freely available at http://parsecnv.sourceforge.net.
doi:10.1093/nar/gks1346
PMCID: PMC3597648  PMID: 23293001
Anney, Richard | Klei, Lambertus | Pinto, Dalila | Almeida, Joana | Bacchelli, Elena | Baird, Gillian | Bolshakova, Nadia | Bölte, Sven | Bolton, Patrick F. | Bourgeron, Thomas | Brennan, Sean | Brian, Jessica | Casey, Jillian | Conroy, Judith | Correia, Catarina | Corsello, Christina | Crawford, Emily L. | de Jonge, Maretha | Delorme, Richard | Duketis, Eftichia | Duque, Frederico | Estes, Annette | Farrar, Penny | Fernandez, Bridget A. | Folstein, Susan E. | Fombonne, Eric | Gilbert, John | Gillberg, Christopher | Glessner, Joseph T. | Green, Andrew | Green, Jonathan | Guter, Stephen J. | Heron, Elizabeth A. | Holt, Richard | Howe, Jennifer L. | Hughes, Gillian | Hus, Vanessa | Igliozzi, Roberta | Jacob, Suma | Kenny, Graham P. | Kim, Cecilia | Kolevzon, Alexander | Kustanovich, Vlad | Lajonchere, Clara M. | Lamb, Janine A. | Law-Smith, Miriam | Leboyer, Marion | Le Couteur, Ann | Leventhal, Bennett L. | Liu, Xiao-Qing | Lombard, Frances | Lord, Catherine | Lotspeich, Linda | Lund, Sabata C. | Magalhaes, Tiago R. | Mantoulan, Carine | McDougle, Christopher J. | Melhem, Nadine M. | Merikangas, Alison | Minshew, Nancy J. | Mirza, Ghazala K. | Munson, Jeff | Noakes, Carolyn | Nygren, Gudrun | Papanikolaou, Katerina | Pagnamenta, Alistair T. | Parrini, Barbara | Paton, Tara | Pickles, Andrew | Posey, David J. | Poustka, Fritz | Ragoussis, Jiannis | Regan, Regina | Roberts, Wendy | Roeder, Kathryn | Roge, Bernadette | Rutter, Michael L. | Schlitt, Sabine | Shah, Naisha | Sheffield, Val C. | Soorya, Latha | Sousa, Inês | Stoppioni, Vera | Sykes, Nuala | Tancredi, Raffaella | Thompson, Ann P. | Thomson, Susanne | Tryfon, Ana | Tsiantis, John | Van Engeland, Herman | Vincent, John B. | Volkmar, Fred | Vorstman, JAS | Wallace, Simon | Wing, Kirsty | Wittemeyer, Kerstin | Wood, Shawn | Zurawiecki, Danielle | Zwaigenbaum, Lonnie | Bailey, Anthony J. | Battaglia, Agatino | Cantor, Rita M. | Coon, Hilary | Cuccaro, Michael L. | Dawson, Geraldine | Ennis, Sean | Freitag, Christine M. | Geschwind, Daniel H. | Haines, Jonathan L. | Klauck, Sabine M. | McMahon, William M. | Maestrini, Elena | Miller, Judith | Monaco, Anthony P. | Nelson, Stanley F. | Nurnberger, John I. | Oliveira, Guiomar | Parr, Jeremy R. | Pericak-Vance, Margaret A. | Piven, Joseph | Schellenberg, Gerard D. | Scherer, Stephen W. | Vicente, Astrid M. | Wassink, Thomas H. | Wijsman, Ellen M. | Betancur, Catalina | Buxbaum, Joseph D. | Cook, Edwin H. | Gallagher, Louise | Gill, Michael | Hallmayer, Joachim | Paterson, Andrew D. | Sutcliffe, James S. | Szatmari, Peter | Vieland, Veronica J. | Hakonarson, Hakon | Devlin, Bernie
Human Molecular Genetics  2012;21(21):4781-4792.
While it is apparent that rare variation can play an important role in the genetic architecture of autism spectrum disorders (ASDs), the contribution of common variation to the risk of developing ASD is less clear. To produce a more comprehensive picture, we report Stage 2 of the Autism Genome Project genome-wide association study, adding 1301 ASD families and bringing the total to 2705 families analysed (Stages 1 and 2). In addition to evaluating the association of individual single nucleotide polymorphisms (SNPs), we also sought evidence that common variants, en masse, might affect the risk. Despite genotyping over a million SNPs covering the genome, no single SNP shows significant association with ASD or selected phenotypes at a genome-wide level. The SNP that achieves the smallest P-value from secondary analyses is rs1718101. It falls in CNTNAP2, a gene previously implicated in susceptibility for ASD. This SNP also shows modest association with age of word/phrase acquisition in ASD subjects, of interest because features of language development are also associated with other variation in CNTNAP2. In contrast, allele scores derived from the transmission of common alleles to Stage 1 cases significantly predict case status in the independent Stage 2 sample. Despite being significant, the variance explained by these allele scores was small (Vm< 1%). Based on results from individual SNPs and their en masse effect on risk, as inferred from the allele score results, it is reasonable to conclude that common variants affect the risk for ASD but their individual effects are modest.
doi:10.1093/hmg/dds301
PMCID: PMC3471395  PMID: 22843504
Human Molecular Genetics  2011;20(11):2285-2295.
Admixture mapping based on recently admixed populations is a powerful method to detect disease variants with substantial allele frequency differences in ancestral populations. We performed admixture mapping analysis for systolic blood pressure (SBP) and diastolic blood pressure (DBP), followed by trait-marker association analysis, in 6303 unrelated African-American participants of the Candidate Gene Association Resource (CARe) consortium. We identified five genomic regions (P< 0.001) harboring genetic variants contributing to inter-individual BP variation. In follow-up association analyses, correcting for all tests performed in this study, three loci were significantly associated with SBP and one significantly associated with DBP (P< 10−5). Further analyses suggested that six independent single-nucleotide polymorphisms (SNPs) contributed to the phenotypic variation observed in the admixture mapping analysis. These six SNPs were examined for replication in multiple, large, independent studies of African-Americans [Women's Health Initiative (WHI), Maywood, Genetic Epidemiology Network of Arteriopathy (GENOA) and Howard University Family Study (HUFS)] as well as one native African sample (Nigerian study), with a total replication sample size of 11 882. Meta-analysis of the replication set identified a novel variant (rs7726475) on chromosome 5 between the SUB1 and NPR3 genes, as being associated with SBP and DBP (P< 0.0015 for both); in meta-analyses combining the CARe samples with the replication data, we observed P-values of 4.45 × 10−7 for SBP and 7.52 × 10−7 for DBP for rs7726475 that were significant after accounting for all the tests performed. Our study highlights that admixture mapping analysis can help identify genetic variants missed by genome-wide association studies because of drastically reduced number of tests in the whole genome.
doi:10.1093/hmg/ddr113
PMCID: PMC3090198  PMID: 21422096
Nature  2010;469(7329):216-220.
Neuroblastoma is a childhood cancer of the sympathetic nervous system that accounts for approximately 10% of all paediatric oncology deaths1,2. To identify genetic risk factors for neuroblastoma, we performed a genome-wide association study (GWAS) on 2,251 patients and 6,097 control subjects of European ancestry from four case series. Here we report a significant association within LIM domain only 1 (LMO1) at 11p15.4 (rs110419, combined P = 5.2 × 10−16, odds ratio of risk allele = 1.34 (95% confidence interval 1.25–1.44)). The signal was enriched in the subset of patients with the most aggressive form of the disease. LMO1 encodes a cysteine-rich transcriptional regulator, and its paralogues (LMO2, LMO3 and LMO4) have each been previously implicated in cancer. In parallel, we analysed genome-wide DNA copy number alterations in 701 primary tumours. We found that the LMO1 locus was aberrant in 12.4% through a duplication event, and that this event was associated with more advanced disease (P < 0.0001) and survival (P = 0.041). The germline single nucleotide polymorphism (SNP) risk alleles and somatic copy number gains were associated with increased LMO1 expression in neuroblastoma cell lines and primary tumours, consistent with a gain-of-function role in tumorigenesis. Short hairpin RNA (shRNA)-mediated depletion of LMO1 inhibited growth of neuroblastoma cells with high LMO1 expression, whereas forced expression of LMO1 in neuroblastoma cells with low LMO1 expression enhanced proliferation. These data show that common polymorphisms at the LMO1 locus are strongly associated with susceptibility to developing neuroblastoma, but also may influence the likelihood of further somatic alterations at this locus, leading to malignant progression.
doi:10.1038/nature09609
PMCID: PMC3320515  PMID: 21124317
PLoS ONE  2012;7(2):10.1371/annotation/a34ee94e-3e6a-48bd-a19e-398a4bb88580.
doi:10.1371/annotation/a34ee94e-3e6a-48bd-a19e-398a4bb88580
PMCID: PMC3293772
Hinch, Anjali G. | Tandon, Arti | Patterson, Nick | Song, Yunli | Rohland, Nadin | Palmer, Cameron D. | Chen, Gary K. | Wang, Kai | Buxbaum, Sarah G. | Akylbekova, Meggie | Aldrich, Melinda C. | Ambrosone, Christine B. | Amos, Christopher | Bandera, Elisa V. | Berndt, Sonja I. | Bernstein, Leslie | Blot, William J. | Bock, Cathryn H. | Boerwinkle, Eric | Cai, Qiuyin | Caporaso, Neil | Casey, Graham | Cupples, L. Adrienne | Deming, Sandra L. | Diver, W. Ryan | Divers, Jasmin | Fornage, Myriam | Gillanders, Elizabeth M. | Glessner, Joseph | Harris, Curtis C. | Hu, Jennifer J. | Ingles, Sue A. | Isaacs, Williams | John, Esther M. | Kao, W. H. Linda | Keating, Brendan | Kittles, Rick A. | Kolonel, Laurence N. | Larkin, Emma | Le Marchand, Loic | McNeill, Lorna H. | Millikan, Robert C. | Murphy, Adam | Musani, Solomon | Neslund-Dudas, Christine | Nyante, Sarah | Papanicolaou, George J. | Press, Michael F. | Psaty, Bruce M. | Reiner, Alex P. | Rich, Stephen S. | Rodriguez-Gil, Jorge L. | Rotter, Jerome I. | Rybicki, Benjamin A. | Schwartz, Ann G. | Signorello, Lisa B. | Spitz, Margaret | Strom, Sara S. | Thun, Michael J. | Tucker, Margaret A. | Wang, Zhaoming | Wiencke, John K. | Witte, John S. | Wrensch, Margaret | Wu, Xifeng | Yamamura, Yuko | Zanetti, Krista A. | Zheng, Wei | Ziegler, Regina G. | Zhu, Xiaofeng | Redline, Susan | Hirschhorn, Joel N. | Henderson, Brian E. | Taylor, Herman A. | Price, Alkes L. | Hakonarson, Hakon | Chanock, Stephen J. | Haiman, Christopher A. | Wilson, James G. | Reich, David | Myers, Simon R.
Nature  2011;476(7359):170-175.
Recombination, together with mutation, is the ultimate source of genetic variation in populations. We leverage the recent mixture of people of African and European ancestry in the Americas to build a genetic map measuring the probability of crossing-over at each position in the genome, based on about 2.1 million crossovers in 30,000 unrelated African Americans. At intervals of more than three megabases it is nearly identical to a map built in Europeans. At finer scales it differs significantly, and we identify about 2,500 recombination hotspots that are active in people of West African ancestry but nearly inactive in Europeans. The probability of a crossover at these hotspots is almost fully controlled by the alleles an individual carries at PRDM9 (P<10−245). We identify a 17 base pair DNA sequence motif that is enriched in these hotspots, and is an excellent match to the predicted binding target of African-enriched alleles of PRDM9.
doi:10.1038/nature10336
PMCID: PMC3154982  PMID: 21775986
Sawcer, Stephen | Hellenthal, Garrett | Pirinen, Matti | Spencer, Chris C.A. | Patsopoulos, Nikolaos A. | Moutsianas, Loukas | Dilthey, Alexander | Su, Zhan | Freeman, Colin | Hunt, Sarah E. | Edkins, Sarah | Gray, Emma | Booth, David R. | Potter, Simon C. | Goris, An | Band, Gavin | Oturai, Annette Bang | Strange, Amy | Saarela, Janna | Bellenguez, Céline | Fontaine, Bertrand | Gillman, Matthew | Hemmer, Bernhard | Gwilliam, Rhian | Zipp, Frauke | Jayakumar, Alagurevathi | Martin, Roland | Leslie, Stephen | Hawkins, Stanley | Giannoulatou, Eleni | D’alfonso, Sandra | Blackburn, Hannah | Boneschi, Filippo Martinelli | Liddle, Jennifer | Harbo, Hanne F. | Perez, Marc L. | Spurkland, Anne | Waller, Matthew J | Mycko, Marcin P. | Ricketts, Michelle | Comabella, Manuel | Hammond, Naomi | Kockum, Ingrid | McCann, Owen T. | Ban, Maria | Whittaker, Pamela | Kemppinen, Anu | Weston, Paul | Hawkins, Clive | Widaa, Sara | Zajicek, John | Dronov, Serge | Robertson, Neil | Bumpstead, Suzannah J. | Barcellos, Lisa F. | Ravindrarajah, Rathi | Abraham, Roby | Alfredsson, Lars | Ardlie, Kristin | Aubin, Cristin | Baker, Amie | Baker, Katharine | Baranzini, Sergio E. | Bergamaschi, Laura | Bergamaschi, Roberto | Bernstein, Allan | Berthele, Achim | Boggild, Mike | Bradfield, Jonathan P. | Brassat, David | Broadley, Simon A. | Buck, Dorothea | Butzkueven, Helmut | Capra, Ruggero | Carroll, William M. | Cavalla, Paola | Celius, Elisabeth G. | Cepok, Sabine | Chiavacci, Rosetta | Clerget-Darpoux, Françoise | Clysters, Katleen | Comi, Giancarlo | Cossburn, Mark | Cournu-Rebeix, Isabelle | Cox, Mathew B. | Cozen, Wendy | Cree, Bruce A.C. | Cross, Anne H. | Cusi, Daniele | Daly, Mark J. | Davis, Emma | de Bakker, Paul I.W. | Debouverie, Marc | D’hooghe, Marie Beatrice | Dixon, Katherine | Dobosi, Rita | Dubois, Bénédicte | Ellinghaus, David | Elovaara, Irina | Esposito, Federica | Fontenille, Claire | Foote, Simon | Franke, Andre | Galimberti, Daniela | Ghezzi, Angelo | Glessner, Joseph | Gomez, Refujia | Gout, Olivier | Graham, Colin | Grant, Struan F.A. | Guerini, Franca Rosa | Hakonarson, Hakon | Hall, Per | Hamsten, Anders | Hartung, Hans-Peter | Heard, Rob N. | Heath, Simon | Hobart, Jeremy | Hoshi, Muna | Infante-Duarte, Carmen | Ingram, Gillian | Ingram, Wendy | Islam, Talat | Jagodic, Maja | Kabesch, Michael | Kermode, Allan G. | Kilpatrick, Trevor J. | Kim, Cecilia | Klopp, Norman | Koivisto, Keijo | Larsson, Malin | Lathrop, Mark | Lechner-Scott, Jeannette S. | Leone, Maurizio A. | Leppä, Virpi | Liljedahl, Ulrika | Bomfim, Izaura Lima | Lincoln, Robin R. | Link, Jenny | Liu, Jianjun | Lorentzen, Åslaug R. | Lupoli, Sara | Macciardi, Fabio | Mack, Thomas | Marriott, Mark | Martinelli, Vittorio | Mason, Deborah | McCauley, Jacob L. | Mentch, Frank | Mero, Inger-Lise | Mihalova, Tania | Montalban, Xavier | Mottershead, John | Myhr, Kjell-Morten | Naldi, Paola | Ollier, William | Page, Alison | Palotie, Aarno | Pelletier, Jean | Piccio, Laura | Pickersgill, Trevor | Piehl, Fredrik | Pobywajlo, Susan | Quach, Hong L. | Ramsay, Patricia P. | Reunanen, Mauri | Reynolds, Richard | Rioux, John D. | Rodegher, Mariaemma | Roesner, Sabine | Rubio, Justin P. | Rückert, Ina-Maria | Salvetti, Marco | Salvi, Erika | Santaniello, Adam | Schaefer, Catherine A. | Schreiber, Stefan | Schulze, Christian | Scott, Rodney J. | Sellebjerg, Finn | Selmaj, Krzysztof W. | Sexton, David | Shen, Ling | Simms-Acuna, Brigid | Skidmore, Sheila | Sleiman, Patrick M.A. | Smestad, Cathrine | Sørensen, Per Soelberg | Søndergaard, Helle Bach | Stankovich, Jim | Strange, Richard C. | Sulonen, Anna-Maija | Sundqvist, Emilie | Syvänen, Ann-Christine | Taddeo, Francesca | Taylor, Bruce | Blackwell, Jenefer M. | Tienari, Pentti | Bramon, Elvira | Tourbah, Ayman | Brown, Matthew A. | Tronczynska, Ewa | Casas, Juan P. | Tubridy, Niall | Corvin, Aiden | Vickery, Jane | Jankowski, Janusz | Villoslada, Pablo | Markus, Hugh S. | Wang, Kai | Mathew, Christopher G. | Wason, James | Palmer, Colin N.A. | Wichmann, H-Erich | Plomin, Robert | Willoughby, Ernest | Rautanen, Anna | Winkelmann, Juliane | Wittig, Michael | Trembath, Richard C. | Yaouanq, Jacqueline | Viswanathan, Ananth C. | Zhang, Haitao | Wood, Nicholas W. | Zuvich, Rebecca | Deloukas, Panos | Langford, Cordelia | Duncanson, Audrey | Oksenberg, Jorge R. | Pericak-Vance, Margaret A. | Haines, Jonathan L. | Olsson, Tomas | Hillert, Jan | Ivinson, Adrian J. | De Jager, Philip L. | Peltonen, Leena | Stewart, Graeme J. | Hafler, David A. | Hauser, Stephen L. | McVean, Gil | Donnelly, Peter | Compston, Alastair
Nature  2011;476(7359):214-219.
Multiple sclerosis (OMIM 126200) is a common disease of the central nervous system in which the interplay between inflammatory and neurodegenerative processes typically results in intermittent neurological disturbance followed by progressive accumulation of disability.1 Epidemiological studies have shown that genetic factors are primarily responsible for the substantially increased frequency of the disease seen in the relatives of affected individuals;2,3 and systematic attempts to identify linkage in multiplex families have confirmed that variation within the Major Histocompatibility Complex (MHC) exerts the greatest individual effect on risk.4 Modestly powered Genome-Wide Association Studies (GWAS)5-10 have enabled more than 20 additional risk loci to be identified and have shown that multiple variants exerting modest individual effects play a key role in disease susceptibility.11 Most of the genetic architecture underlying susceptibility to the disease remains to be defined and is anticipated to require the analysis of sample sizes that are beyond the numbers currently available to individual research groups. In a collaborative GWAS involving 9772 cases of European descent collected by 23 research groups working in 15 different countries, we have replicated almost all of the previously suggested associations and identified at least a further 29 novel susceptibility loci. Within the MHC we have refined the identity of the DRB1 risk alleles and confirmed that variation in the HLA-A gene underlies the independent protective effect attributable to the Class I region. Immunologically relevant genes are significantly over-represented amongst those mapping close to the identified loci and particularly implicate T helper cell differentiation in the pathogenesis of multiple sclerosis.
doi:10.1038/nature10251
PMCID: PMC3182531  PMID: 21833088
multiple sclerosis; GWAS; genetics
Nature Genetics  2009;41(12):1335-1340.
The inflammatory bowel diseases (IBD) Crohn’s disease and ulcerative colitis are common causes of morbidity in children and young adults in the western world. Here we report the results of a genome-wide association study in early-onset IBD involving 3,426 affected individuals and 11,963 genetically matched controls recruited through international collaborations in Europe and North America, thereby extending the results from a previous study of 1,011 individuals with early-onset IBD1. We have identified five new regions associated with early-onset IBD susceptibility, including 16p11 near the cytokine gene IL27 (rs8049439, P = 2.41 × 10−9), 22q12 (rs2412973, P = 1.55 × 10−9), 10q22 (rs1250550, P = 5.63 × 10−9), 2q37 (rs4676410, P = 3.64 × 10−8) and 19q13.11 (rs10500264, P = 4.26 × 10−10). Our scan also detected associations at 23 of 32 loci previously implicated in adult-onset Crohn’s disease and at 8 of 17 loci implicated in adult-onset ulcerative colitis, highlighting the close pathogenetic relationship between early- and adult-onset IBD.
doi:10.1038/ng.489
PMCID: PMC3267927  PMID: 19915574
Casey, Jillian P. | Magalhaes, Tiago | Conroy, Judith M. | Regan, Regina | Shah, Naisha | Anney, Richard | Shields, Denis C. | Abrahams, Brett S. | Almeida, Joana | Bacchelli, Elena | Bailey, Anthony J. | Baird, Gillian | Battaglia, Agatino | Berney, Tom | Bolshakova, Nadia | Bolton, Patrick F. | Bourgeron, Thomas | Brennan, Sean | Cali, Phil | Correia, Catarina | Corsello, Christina | Coutanche, Marc | Dawson, Geraldine | de Jonge, Maretha | Delorme, Richard | Duketis, Eftichia | Duque, Frederico | Estes, Annette | Farrar, Penny | Fernandez, Bridget A. | Folstein, Susan E. | Foley, Suzanne | Fombonne, Eric | Freitag, Christine M. | Gilbert, John | Gillberg, Christopher | Glessner, Joseph T. | Green, Jonathan | Guter, Stephen J. | Hakonarson, Hakon | Holt, Richard | Hughes, Gillian | Hus, Vanessa | Igliozzi, Roberta | Kim, Cecilia | Klauck, Sabine M. | Kolevzon, Alexander | Lamb, Janine A. | Leboyer, Marion | Le Couteur, Ann | Leventhal, Bennett L. | Lord, Catherine | Lund, Sabata C. | Maestrini, Elena | Mantoulan, Carine | Marshall, Christian R. | McConachie, Helen | McDougle, Christopher J. | McGrath, Jane | McMahon, William M. | Merikangas, Alison | Miller, Judith | Minopoli, Fiorella | Mirza, Ghazala K. | Munson, Jeff | Nelson, Stanley F. | Nygren, Gudrun | Oliveira, Guiomar | Pagnamenta, Alistair T. | Papanikolaou, Katerina | Parr, Jeremy R. | Parrini, Barbara | Pickles, Andrew | Pinto, Dalila | Piven, Joseph | Posey, David J. | Poustka, Annemarie | Poustka, Fritz | Ragoussis, Jiannis | Roge, Bernadette | Rutter, Michael L. | Sequeira, Ana F. | Soorya, Latha | Sousa, Inês | Sykes, Nuala | Stoppioni, Vera | Tancredi, Raffaella | Tauber, Maïté | Thompson, Ann P. | Thomson, Susanne | Tsiantis, John | Van Engeland, Herman | Vincent, John B. | Volkmar, Fred | Vorstman, Jacob A. S. | Wallace, Simon | Wang, Kai | Wassink, Thomas H. | White, Kathy | Wing, Kirsty | Wittemeyer, Kerstin | Yaspan, Brian L. | Zwaigenbaum, Lonnie | Betancur, Catalina | Buxbaum, Joseph D. | Cantor, Rita M. | Cook, Edwin H. | Coon, Hilary | Cuccaro, Michael L. | Geschwind, Daniel H. | Haines, Jonathan L. | Hallmayer, Joachim | Monaco, Anthony P. | Nurnberger, John I. | Pericak-Vance, Margaret A. | Schellenberg, Gerard D. | Scherer, Stephen W. | Sutcliffe, James S. | Szatmari, Peter | Vieland, Veronica J. | Wijsman, Ellen M. | Green, Andrew | Gill, Michael | Gallagher, Louise | Vicente, Astrid | Ennis, Sean
Human Genetics  2011;131(4):565-579.
Autism spectrum disorder (ASD) is a highly heritable disorder of complex and heterogeneous aetiology. It is primarily characterized by altered cognitive ability including impaired language and communication skills and fundamental deficits in social reciprocity. Despite some notable successes in neuropsychiatric genetics, overall, the high heritability of ASD (~90%) remains poorly explained by common genetic risk variants. However, recent studies suggest that rare genomic variation, in particular copy number variation, may account for a significant proportion of the genetic basis of ASD. We present a large scale analysis to identify candidate genes which may contain low-frequency recessive variation contributing to ASD while taking into account the potential contribution of population differences to the genetic heterogeneity of ASD. Our strategy, homozygous haplotype (HH) mapping, aims to detect homozygous segments of identical haplotype structure that are shared at a higher frequency amongst ASD patients compared to parental controls. The analysis was performed on 1,402 Autism Genome Project trios genotyped for 1 million single nucleotide polymorphisms (SNPs). We identified 25 known and 1,218 novel ASD candidate genes in the discovery analysis including CADM2, ABHD14A, CHRFAM7A, GRIK2, GRM3, EPHA3, FGF10, KCND2, PDZK1, IMMP2L and FOXP2. Furthermore, 10 of the previously reported ASD genes and 300 of the novel candidates identified in the discovery analysis were replicated in an independent sample of 1,182 trios. Our results demonstrate that regions of HH are significantly enriched for previously reported ASD candidate genes and the observed association is independent of gene size (odds ratio 2.10). Our findings highlight the applicability of HH mapping in complex disorders such as ASD and offer an alternative approach to the analysis of genome-wide association data.
Electronic supplementary material
The online version of this article (doi:10.1007/s00439-011-1094-6) contains supplementary material, which is available to authorized users.
doi:10.1007/s00439-011-1094-6
PMCID: PMC3303079  PMID: 21996756
Diabetes  2010;59(10):2690-2694.
OBJECTIVE
Obesity is an increasingly common disorder that predisposes to several medical conditions, including type 2 diabetes. We investigated whether large and rare copy-number variations (CNVs) differentiate moderate to extreme obesity from never-overweight control subjects.
RESEARCH DESIGN AND METHODS
Using single nucleotide polymorphism (SNP) arrays, we performed a genome-wide CNV survey on 430 obese case subjects (BMI >35 kg/m2) and 379 never-overweight control subjects (BMI <25 kg/m2). All subjects were of European ancestry and were genotyped on the Illumina HumanHap550 arrays with ∼550,000 SNP markers. The CNV calls were generated by PennCNV software.
RESULTS
CNVs >1 Mb were found to be overrepresented in case versus control subjects (odds ratio [OR] = 1.5 [95% CI 0.5–5]), and CNVs >2 Mb were present in 1.3% of the case subjects but were absent in control subjects (OR = infinity [95% CI 1.2–infinity]). When focusing on rare deletions that disrupt genes, even more pronounced effect sizes are observed (OR = 2.7 [95% CI 0.5–27.1] for CNVs >1 Mb). Interestingly, obese case subjects who carry these large CNVs have moderately high BMI and do not appear to be extreme cases. Several CNVs disrupt known candidate genes for obesity, such as a 3.3-Mb deletion disrupting NAP1L5 and a 2.1-Mb deletion disrupting UCP1 and IL15.
CONCLUSIONS
Our results suggest that large CNVs, especially rare deletions, confer risk of obesity in patients with moderate obesity and that genes impacted by large CNVs represent intriguing candidates for obesity that warrant further study.
doi:10.2337/db10-0192
PMCID: PMC3279563  PMID: 20622171

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