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author:("harris, Maria")
1.  Genome-wide copy number variation study associates metabotropic glutamate receptor gene networks with attention deficit hyperactivity disorder 
Nature genetics  2011;44(1):78-84.
Attention deficit hyperactivity disorder (ADHD) is a common, heritable neuropsychiatric disorder of unknown etiology. We performed a whole-genome copy number variation (CNV) study on 1,013 cases with ADHD and 4,105 healthy children of European ancestry using 550,000 SNPs. We evaluated statistically significant findings in multiple independent cohorts, with a total of 2,493 cases with ADHD and 9,222 controls of European ancestry, using matched platforms. CNVs affecting metabotropic glutamate receptor genes were enriched across all cohorts (P = 2.1 × 10−9). We saw GRM5 (encoding glutamate receptor, metabotropic 5) deletions in ten cases and one control (P = 1.36 × 10−6). We saw GRM7 deletions in six cases, and we saw GRM8 deletions in eight cases and no controls. GRM1 was duplicated in eight cases. We experimentally validated the observed variants using quantitative RT-PCR. A gene network analysis showed that genes interacting with the genes in the GRM family are enriched for CNVs in ~10% of the cases (P = 4.38 × 10−10) after correction for occurrence in the controls. We identified rare recurrent CNVs affecting glutamatergic neurotransmission genes that were overrepresented in multiple ADHD cohorts.
PMCID: PMC4310555  PMID: 22138692
2.  Integrative genomics identifies LMO1 as a neuroblastoma oncogene 
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.
PMCID: PMC3320515  PMID: 21124317
3.  Comparative genetic analysis of inflammatory bowel disease and type 1 diabetes implicates multiple loci with opposite effects 
Human Molecular Genetics  2010;19(10):2059-2067.
Inflammatory bowel disease, including Crohn's disease (CD) and ulcerative colitis (UC), and type 1 diabetes (T1D) are autoimmune diseases that may share common susceptibility pathways. We examined known susceptibility loci for these diseases in a cohort of 1689 CD cases, 777 UC cases, 989 T1D cases and 6197 shared control subjects of European ancestry, who were genotyped by the Illumina HumanHap550 SNP arrays. We identified multiple previously unreported or unconfirmed disease associations, including known CD loci (ICOSLG and TNFSF15) and T1D loci (TNFAIP3) that confer UC risk, known UC loci (HERC2 and IL26) that confer T1D risk and known UC loci (IL10 and CCNY) that confer CD risk. Additionally, we show that T1D risk alleles residing at the PTPN22, IL27, IL18RAP and IL10 loci protect against CD. Furthermore, the strongest risk alleles for T1D within the major histocompatibility complex (MHC) confer strong protection against CD and UC; however, given the multi-allelic nature of the MHC haplotypes, sequencing of the MHC locus will be required to interpret this observation. These results extend our current knowledge on genetic variants that predispose to autoimmunity, and suggest that many loci involved in autoimmunity may be under a balancing selection due to antagonistic pleiotropic effect. Our analysis implies that variants with opposite effects on different diseases may facilitate the maintenance of common susceptibility alleles in human populations, making autoimmune diseases especially amenable to genetic dissection by genome-wide association studies.
PMCID: PMC2860894  PMID: 20176734
4.  Examination of All Type 2 Diabetes GWAS Loci Reveals HHEX-IDE as a Locus Influencing Pediatric BMI 
Diabetes  2009;59(3):751-755.
A number of studies have found that BMI in early life influences the risk of developing type 2 diabetes later in life. Our goal was to investigate if any type 2 diabetes variants uncovered through genome-wide association studies (GWAS) impact BMI in childhood.
Using data from an ongoing GWAS of pediatric BMI in our cohort, we investigated the association of pediatric BMI with 20 single nucleotide polymorphisms at 18 type 2 diabetes loci uncovered through GWAS, consisting of ADAMTS9, CDC123-CAMK1D, CDKAL1, CDKN2A/B, EXT2, FTO, HHEX-IDE, IGF2BP2, the intragenic region on 11p12, JAZF1, KCNQ1, LOC387761, MTNR1B, NOTCH2, SLC30A8, TCF7L2, THADA, and TSPAN8-LGR5. We randomly partitioned our cohort exactly in half in order to have a discovery cohort (n = 3,592) and a replication cohort (n = 3,592).
Our data show that the major type 2 diabetes risk–conferring G allele of rs7923837 at the HHEX-IDE locus was associated with higher pediatric BMI in both the discovery (P = 0.0013 and survived correction for 20 tests) and replication (P = 0.023) sets (combined P = 1.01 × 10−4). Association was not detected with any other known type 2 diabetes loci uncovered to date through GWAS except for the well-established FTO.
Our data show that the same genetic HHEX-IDE variant, which is associated with type 2 diabetes from previous studies, also influences pediatric BMI.
PMCID: PMC2828649  PMID: 19933996
5.  Examination of Type 2 Diabetes Loci Implicates CDKAL1 as a Birth Weight Gene 
Diabetes  2009;58(10):2414-2418.
A number of studies have found that reduced birth weight is associated with type 2 diabetes later in life; however, the underlying mechanism for this correlation remains unresolved. Recently, association has been demonstrated between low birth weight and single nucleotide polymorphisms (SNPs) at the CDKAL1 and HHEX-IDE loci, regions that were previously implicated in the pathogenesis of type 2 diabetes. In order to investigate whether type 2 diabetes risk–conferring alleles associate with low birth weight in our Caucasian childhood cohort, we examined the effects of 20 such loci on this trait.
Using data from an ongoing genome-wide association study in our cohort of 5,465 Caucasian children with recorded birth weights, we investigated the association of the previously reported type 2 diabetes–associated variation at 20 loci including TCF7L2, HHEX-IDE, PPARG, KCNJ11, SLC30A8, IGF2BP2, CDKAL1, CDKN2A/2B, and JAZF1 with birth weight.
Our data show that the minor allele of rs7756992 (P = 8 × 10−5) at the CDKAL1 locus is strongly associated with lower birth weight, whereas a perfect surrogate for variation previously implicated for the trait at the same locus only yielded nominally significant association (P = 0.01; r2 rs7756992 = 0.677). However, association was not detected with any of the other type 2 diabetes loci studied.
We observe association between lower birth weight and type 2 diabetes risk–conferring alleles at the CDKAL1 locus. Our data show that the same genetic locus that has been identified as a marker for type 2 diabetes in previous studies also influences birth weight.
PMCID: PMC2750235  PMID: 19592620
6.  Autism genome-wide copy number variation reveals ubiquitin and neuronal genes 
Nature  2009;459(7246):569-573.
Autism spectrum disorders (ASDs) are childhood neurodevelopmental disorders with complex genetic origins1–4. Previous studies focusing on candidate genes or genomic regions have identified several copy number variations (CNVs) that are associated with an increased risk of ASDs5–9. Here we present the results from a whole-genome CNV study on a cohort of 859 ASD cases and 1,409 healthy children of European ancestry who were genotyped with ~550,000 single nucleotide polymorphism markers, in an attempt to comprehensively identify CNVs conferring susceptibility to ASDs. Positive findings were evaluated in an independent cohort of 1,336 ASD cases and 1,110 controls of European ancestry. Besides previously reported ASD candidate genes, such as NRXN1 (ref. 10) and CNTN4 (refs 11, 12), several new susceptibility genes encoding neuronal cell-adhesion molecules, including NLGN1 and ASTN2, were enriched with CNVs in ASD cases compared to controls (P = 9.5 × 10−3). Furthermore, CNVs within or surrounding genes involved in the ubiquitin pathways, including UBE3A, PARK2, RFWD2 and FBXO40, were affected by CNVs not observed in controls (P = 3.3 × 10−3). We also identified duplications 55 kilobases upstream of complementary DNA AK123120 (P = 3.6 × 10−6). Although these variants may be individually rare, they target genes involved in neuronal cell-adhesion or ubiquitin degradation, indicating that these two important gene networks expressed within the central nervous system may contribute to the genetic susceptibility of ASD.
PMCID: PMC2925224  PMID: 19404257
7.  The role of height-associated loci identified in genome wide association studies in the determination of pediatric stature 
BMC Medical Genetics  2010;11:96.
Human height is considered highly heritable and correlated with certain disorders, such as type 2 diabetes and cancer. Despite environmental influences, genetic factors are known to play an important role in stature determination. A number of genetic determinants of adult height have already been established through genome wide association studies.
To examine 51 single nucleotide polymorphisms (SNPs) corresponding to the 46 previously reported genomic loci for height in 8,184 European American children with height measurements. We leveraged genotyping data from our ongoing GWA study of height variation in children in order to query the 51 SNPs in this pediatric cohort.
Sixteen of these SNPs yielded at least nominally significant association to height, representing fifteen different loci including EFEMP1-PNPT1, GPR126, C6orf173, SPAG17, Histone class 1, HLA class III and GDF5-UQCC. Other loci revealed no evidence for association, including HMGA1 and HMGA2. For the 16 associated variants, the genotype score explained 1.64% of the total variation for height z-score.
Among 46 loci that have been reported to associate with adult height to date, at least 15 also contribute to the determination of height in childhood.
PMCID: PMC2894790  PMID: 20546612
8.  The role of obesity-associated loci identified in genome wide association studies in the determination of pediatric BMI 
Obesity (Silver Spring, Md.)  2009;17(12):2254-2257.
The prevalence of obesity in children and adults in the United States has increased dramatically over the past decade. Besides environmental factors, genetic factors are known to play an important role in the pathogenesis of obesity. A number of genetic determinants of adult BMI have already been established through genome wide association studies. In this study, we examined 25 single nucleotide polymorphisms (SNPs) corresponding to thirteen previously reported genomic loci in 6,078 children with measures of BMI. Fifteen of these SNPs yielded at least nominally significant association to BMI, representing nine different loci including INSIG2, FTO, MC4R, TMEM18, GNPDA2, NEGR1, BDNF, KCTD15 and 1q25. Other loci revealed no evidence for association, namely at MTCH2, SH2B1, 12q13 and 3q27. For the 15 associated variants, the genotype score explained 1.12% of the total variation for BMI z-score. We conclude that among thirteen loci that have been reported to associate with adult BMI, at least nine also contribute to the determination of BMI in childhood as demonstrated by their associations in our pediatric cohort.
PMCID: PMC2860782  PMID: 19478790
9.  Investigation of the locus near MC4R with childhood obesity in Americans of European and African ancestry 
Obesity (Silver Spring, Md.)  2009;17(7):1461-1465.
Recently a modest, but consistently, replicated association was demonstrated between obesity and the single nucleotide polymorphism (SNP), rs17782313, 3’ of the MC4R locus as a consequence of a meta-analysis of genome wide association (GWA) studies of the disease in Caucasian populations. We investigated the association in the context of the childhood form of the disease utilizing data from our ongoing GWA study in a cohort of 728 European American (EA) obese children (BMI ≥ 95th percentile) and 3,960 EA controls (BMI < 95th percentile), as well as 1,008 African American (AA) obese children and 2,715 AA controls. rs571312, rs10871777 and rs476828 (perfect surrogates for rs17782313) yielded odds ratios in the EA cohort of 1.142 (P = 0.045), 1.137 (P = 0.054) and 1.145 (P = 0.042); however, there was no significant association with these SNPs in the AA cohort. When investigating all thirty SNPs present on the Illumina BeadChip at this locus, again there was no evidence for association in AA cases when correcting for the number of tests employed. As such, variants 3’ to the MC4R locus present on the genotyping platform utilized confer a similar magnitude of risk of obesity in Caucasian children as to their adult Caucasian counterparts but this observation did not extend to African Americans.
PMCID: PMC2860794  PMID: 19265794
10.  Common variations in BARD1 influence susceptibility to high-risk neuroblastoma 
Nature genetics  2009;41(6):718-723.
We conducted a SNP-based genome-wide association study (GWAS) focused on the high-risk subset of neuroblastoma1. As our previous unbiased GWAS showed strong association of common 6p22 SNP alleles with aggressive neuroblastoma2, we now restricted our analysis to 397 high-risk cases compared to 2,043 controls. We detected new significant association of six SNPs at 2q35 within the BARD1 gene locus (Pallelic = 2.35×10−9 − 2.25×10−8). Each SNP association was confirmed in a second series of 189 high-risk cases and 1,178 controls (Pallelic = 7.90×10−7 − 2.77×10−4). The two most significant SNPs (rs6435862, rs3768716) were also tested in two additional independent high-risk neuroblastoma case series, yielding combined allelic odds-ratios of 1.68 each (P = 8.65×10−18 and 2.74×10−16, respectively). Significant association was also found with known BARD1 nsSNPs. These data show that common variation in BARD1 contributes to the etiology of the aggressive and most clinically relevant subset of human neuroblastoma.
PMCID: PMC2753610  PMID: 19412175

Results 1-10 (10)