PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-10 (10)
 

Clipboard (0)
None

Select a Filter Below

Journals
Year of Publication
Document Types
1.  Testing for association of the monoamine oxidase A promoter polymorphism with brain structure volumes in both autism and the fragile X syndrome 
Background
Autism and the fragile X syndrome (FXS) are related to each other genetically and symptomatically. A cardinal biological feature of both disorders is abnormalities of cerebral cortical brain volumes. We have previously shown that the monoamine oxidase A (MAOA) promoter polymorphism is associated with cerebral cortical volumes in children with autism, and we now sought to determine whether the association was also present in children with FXS.
Methods
Participants included 47 2-year-old Caucasian boys with FXS, some of whom also had autism, as well as 34 2-year-old boys with idiopathic autism analyzed in a previous study. The MAOA promoter polymorphism was genotyped and tested for relationships with gray and white matter volumes of the cerebral cortical lobes and cerebro-spinal fluid volume of the lateral ventricles.
Results
MAOA genotype effects in FXS children were the same as those previously observed in idiopathic autism: the low activity MAOA promoter polymorphism allele was associated with increased gray and white matter volumes in all cerebral lobes. The effect was most pronounced in frontal lobe gray matter and all three white matter regions: frontal gray, F = 4.39, P = 0.04; frontal white, F = 5.71, P = 0.02; temporal white, F = 4.73, P = 0.04; parieto-occipital white, F = 5.00, P = 0.03. Analysis of combined FXS and idiopathic autism samples produced P values for these regions <0.01 and effect sizes of approximately 0.10.
Conclusions
The MAOA promoter polymorphism is similarly associated with brain structure volumes in both idiopathic autism and FXS. These data illuminate a number of important aspects of autism and FXS heritability: a genetic effect on a core biological trait of illness, the specificity/generalizability of the genetic effect, and the utility of examining individual genetic effects on the background of a single gene disorder such as FXS.
doi:10.1186/1866-1955-6-6
PMCID: PMC3987046  PMID: 24669826
Autism; Fragile X syndrome; Brain structure; Monoamine oxidase A; Polymorphism
2.  Loci nominally associated with autism from genome-wide analysis show enrichment of brain expression quantitative trait loci but not lymphoblastoid cell line expression quantitative trait loci 
Molecular Autism  2012;3:3.
Background
Autism spectrum disorder is a severe early onset neurodevelopmental disorder with high heritability but significant heterogeneity. Traditional genome-wide approaches to test for an association of common variants with autism susceptibility risk have met with limited success. However, novel methods to identify moderate risk alleles in attainable sample sizes are now gaining momentum.
Methods
In this study, we utilized publically available genome-wide association study data from the Autism Genome Project and annotated the results (P <0.001) for expression quantitative trait loci present in the parietal lobe (GSE35977), cerebellum (GSE35974) and lymphoblastoid cell lines (GSE7761). We then performed a test of enrichment by comparing these results to simulated data conditioned on minor allele frequency to generate an empirical P-value indicating statistically significant enrichment of expression quantitative trait loci in top results from the autism genome-wide association study.
Results
Our findings show a global enrichment of brain expression quantitative trait loci, but not lymphoblastoid cell line expression quantitative trait loci, among top single nucleotide polymorphisms from an autism genome-wide association study. Additionally, the data implicates individual genes SLC25A12, PANX1 and PANX2 as well as pathways previously implicated in autism.
Conclusions
These findings provide supportive rationale for the use of annotation-based approaches to genome-wide association studies.
doi:10.1186/2040-2392-3-3
PMCID: PMC3484025  PMID: 22591576
Autism; annotation; cerebellum; enrichment; expression quantitative trait (eQTL); GWAS; LCL; pannexin; parietal; SLC25A12
3.  Genome-wide association study of Tourette Syndrome 
Scharf, Jeremiah M. | Yu, Dongmei | Mathews, Carol A. | Neale, Benjamin M. | Stewart, S. Evelyn | Fagerness, Jesen A | Evans, Patrick | Gamazon, Eric | Edlund, Christopher K. | Service, Susan | Tikhomirov, Anna | Osiecki, Lisa | Illmann, Cornelia | Pluzhnikov, Anna | Konkashbaev, Anuar | Davis, Lea K | Han, Buhm | Crane, Jacquelyn | Moorjani, Priya | Crenshaw, Andrew T. | Parkin, Melissa A. | Reus, Victor I. | Lowe, Thomas L. | Rangel-Lugo, Martha | Chouinard, Sylvain | Dion, Yves | Girard, Simon | Cath, Danielle C | Smit, Jan H | King, Robert A. | Fernandez, Thomas | Leckman, James F. | Kidd, Kenneth K. | Kidd, Judith R. | Pakstis, Andrew J. | State, Matthew | Herrera, Luis Diego | Romero, Roxana | Fournier, Eduardo | Sandor, Paul | Barr, Cathy L | Phan, Nam | Gross-Tsur, Varda | Benarroch, Fortu | Pollak, Yehuda | Budman, Cathy L. | Bruun, Ruth D. | Erenberg, Gerald | Naarden, Allan L | Lee, Paul C | Weiss, Nicholas | Kremeyer, Barbara | Berrío, Gabriel Bedoya | Campbell, Desmond | Silgado, Julio C. Cardona | Ochoa, William Cornejo | Restrepo, Sandra C. Mesa | Muller, Heike | Duarte, Ana V. Valencia | Lyon, Gholson J | Leppert, Mark | Morgan, Jubel | Weiss, Robert | Grados, Marco A. | Anderson, Kelley | Davarya, Sarah | Singer, Harvey | Walkup, John | Jankovic, Joseph | Tischfield, Jay A. | Heiman, Gary A. | Gilbert, Donald L. | Hoekstra, Pieter J. | Robertson, Mary M. | Kurlan, Roger | Liu, Chunyu | Gibbs, J. Raphael | Singleton, Andrew | Hardy, John | Strengman, Eric | Ophoff, Roel | Wagner, Michael | Moessner, Rainald | Mirel, Daniel B. | Posthuma, Danielle | Sabatti, Chiara | Eskin, Eleazar | Conti, David V. | Knowles, James A. | Ruiz-Linares, Andres | Rouleau, Guy A. | Purcell, Shaun | Heutink, Peter | Oostra, Ben A. | McMahon, William | Freimer, Nelson | Cox, Nancy J. | Pauls, David L.
Molecular psychiatry  2012;18(6):721-728.
Tourette Syndrome (TS) is a developmental disorder that has one of the highest familial recurrence rates among neuropsychiatric diseases with complex inheritance. However, the identification of definitive TS susceptibility genes remains elusive. Here, we report the first genome-wide association study (GWAS) of TS in 1285 cases and 4964 ancestry-matched controls of European ancestry, including two European-derived population isolates, Ashkenazi Jews from North America and Israel, and French Canadians from Quebec, Canada. In a primary meta-analysis of GWAS data from these European ancestry samples, no markers achieved a genome-wide threshold of significance (p<5 × 10−8); the top signal was found in rs7868992 on chromosome 9q32 within COL27A1 (p=1.85 × 10−6). A secondary analysis including an additional 211 cases and 285 controls from two closely-related Latin-American population isolates from the Central Valley of Costa Rica and Antioquia, Colombia also identified rs7868992 as the top signal (p=3.6 × 10−7 for the combined sample of 1496 cases and 5249 controls following imputation with 1000 Genomes data). This study lays the groundwork for the eventual identification of common TS susceptibility variants in larger cohorts and helps to provide a more complete understanding of the full genetic architecture of this disorder.
doi:10.1038/mp.2012.69
PMCID: PMC3605224  PMID: 22889924
Tourette Syndrome; tics; genetics; GWAS; neurodevelopmental disorder
4.  Partitioning the Heritability of Tourette Syndrome and Obsessive Compulsive Disorder Reveals Differences in Genetic Architecture 
Davis, Lea K. | Yu, Dongmei | Keenan, Clare L. | Gamazon, Eric R. | Konkashbaev, Anuar I. | Derks, Eske M. | Neale, Benjamin M. | Yang, Jian | Lee, S. Hong | Evans, Patrick | Barr, Cathy L. | Bellodi, Laura | Benarroch, Fortu | Berrio, Gabriel Bedoya | Bienvenu, Oscar J. | Bloch, Michael H. | Blom, Rianne M. | Bruun, Ruth D. | Budman, Cathy L. | Camarena, Beatriz | Campbell, Desmond | Cappi, Carolina | Cardona Silgado, Julio C. | Cath, Danielle C. | Cavallini, Maria C. | Chavira, Denise A. | Chouinard, Sylvain | Conti, David V. | Cook, Edwin H. | Coric, Vladimir | Cullen, Bernadette A. | Deforce, Dieter | Delorme, Richard | Dion, Yves | Edlund, Christopher K. | Egberts, Karin | Falkai, Peter | Fernandez, Thomas V. | Gallagher, Patience J. | Garrido, Helena | Geller, Daniel | Girard, Simon L. | Grabe, Hans J. | Grados, Marco A. | Greenberg, Benjamin D. | Gross-Tsur, Varda | Haddad, Stephen | Heiman, Gary A. | Hemmings, Sian M. J. | Hounie, Ana G. | Illmann, Cornelia | Jankovic, Joseph | Jenike, Michael A. | Kennedy, James L. | King, Robert A. | Kremeyer, Barbara | Kurlan, Roger | Lanzagorta, Nuria | Leboyer, Marion | Leckman, James F. | Lennertz, Leonhard | Liu, Chunyu | Lochner, Christine | Lowe, Thomas L. | Macciardi, Fabio | McCracken, James T. | McGrath, Lauren M. | Mesa Restrepo, Sandra C. | Moessner, Rainald | Morgan, Jubel | Muller, Heike | Murphy, Dennis L. | Naarden, Allan L. | Ochoa, William Cornejo | Ophoff, Roel A. | Osiecki, Lisa | Pakstis, Andrew J. | Pato, Michele T. | Pato, Carlos N. | Piacentini, John | Pittenger, Christopher | Pollak, Yehuda | Rauch, Scott L. | Renner, Tobias J. | Reus, Victor I. | Richter, Margaret A. | Riddle, Mark A. | Robertson, Mary M. | Romero, Roxana | Rosàrio, Maria C. | Rosenberg, David | Rouleau, Guy A. | Ruhrmann, Stephan | Ruiz-Linares, Andres | Sampaio, Aline S. | Samuels, Jack | Sandor, Paul | Sheppard, Brooke | Singer, Harvey S. | Smit, Jan H. | Stein, Dan J. | Strengman, E. | Tischfield, Jay A. | Valencia Duarte, Ana V. | Vallada, Homero | Van Nieuwerburgh, Filip | Veenstra-VanderWeele, Jeremy | Walitza, Susanne | Wang, Ying | Wendland, Jens R. | Westenberg, Herman G. M. | Shugart, Yin Yao | Miguel, Euripedes C. | McMahon, William | Wagner, Michael | Nicolini, Humberto | Posthuma, Danielle | Hanna, Gregory L. | Heutink, Peter | Denys, Damiaan | Arnold, Paul D. | Oostra, Ben A. | Nestadt, Gerald | Freimer, Nelson B. | Pauls, David L. | Wray, Naomi R. | Stewart, S. Evelyn | Mathews, Carol A. | Knowles, James A. | Cox, Nancy J. | Scharf, Jeremiah M.
PLoS Genetics  2013;9(10):e1003864.
The direct estimation of heritability from genome-wide common variant data as implemented in the program Genome-wide Complex Trait Analysis (GCTA) has provided a means to quantify heritability attributable to all interrogated variants. We have quantified the variance in liability to disease explained by all SNPs for two phenotypically-related neurobehavioral disorders, obsessive-compulsive disorder (OCD) and Tourette Syndrome (TS), using GCTA. Our analysis yielded a heritability point estimate of 0.58 (se = 0.09, p = 5.64e-12) for TS, and 0.37 (se = 0.07, p = 1.5e-07) for OCD. In addition, we conducted multiple genomic partitioning analyses to identify genomic elements that concentrate this heritability. We examined genomic architectures of TS and OCD by chromosome, MAF bin, and functional annotations. In addition, we assessed heritability for early onset and adult onset OCD. Among other notable results, we found that SNPs with a minor allele frequency of less than 5% accounted for 21% of the TS heritability and 0% of the OCD heritability. Additionally, we identified a significant contribution to TS and OCD heritability by variants significantly associated with gene expression in two regions of the brain (parietal cortex and cerebellum) for which we had available expression quantitative trait loci (eQTLs). Finally we analyzed the genetic correlation between TS and OCD, revealing a genetic correlation of 0.41 (se = 0.15, p = 0.002). These results are very close to previous heritability estimates for TS and OCD based on twin and family studies, suggesting that very little, if any, heritability is truly missing (i.e., unassayed) from TS and OCD GWAS studies of common variation. The results also indicate that there is some genetic overlap between these two phenotypically-related neuropsychiatric disorders, but suggest that the two disorders have distinct genetic architectures.
Author Summary
Family and twin studies have shown that genetic risk factors are important in the development of Tourette Syndrome (TS) and obsessive compulsive disorder (OCD). However, efforts to identify the individual genetic risk factors involved in these two neuropsychiatric disorders have been largely unsuccessful. One possible explanation for this is that many genetic variations scattered throughout the genome each contribute a small amount to the overall risk. For TS and OCD, the genetic architecture (characterized by the number, frequency, and distribution of genetic risk factors) is presently unknown. This study examined the genetic architecture of TS and OCD in a variety of ways. We found that rare genetic changes account for more genetic risk in TS than in OCD; certain chromosomes contribute to OCD risk more than others; and variants that influence the level of genes expressed in two regions of the brain can account for a significant amount of risk for both TS and OCD. Results from this study might help in determining where, and what kind of variants are individual risk factors for TS and OCD and where they might be located in the human genome.
doi:10.1371/journal.pgen.1003864
PMCID: PMC3812053  PMID: 24204291
5.  Cortical Enlargement in Autism is Associated With a Functional VNTR in the Monoamine Oxidase A Gene 
Monoamine oxidase A (MAOA) is an enzyme expressed in the brain that metabolizes dopamine, norepinephrine, epinephrine, and serotonin. Abnormalities of serotonin neurotransmission have long been implicated in the psychopathology of autism. A polymorphism exists within the promoter region of the MAOA gene that influences MAOA expression levels so that “low activity” alleles are associated with increased neurotransmitter levels in the brain. Individuals with autism often exhibit elevated serotonin levels. Additional studies indicate that the “low activity” allele may be associated with lower IQ and more severe autistic symptoms. In this study we genotyped the MAOA promoter polymorphism in a group of 29 males (age 2–3 years) with autism and a group of 39 healthy pediatric controls for whom brain MRI data was available. We found a consistent association between the “low activity” allele and larger brain volumes for regions of the cortex in children with autism but not in controls. We did not find evidence for over-transmission of the “low activity” allele in a separate sample of 114 affected sib pairfamilies. Nor did we find any unknown SNPs in yet another sample of 96 probands. Future studies will determine if there is a more severe clinical phenotype associated with both the “low activity” genotype and the larger brain volumes in our sample.
doi:10.1002/ajmg.b.30738
PMCID: PMC2752707  PMID: 18361446
autism; MAOA; neuroimaging; genetics
6.  Genome-wide analysis of copy number variants in age-related macular degeneration 
Human genetics  2010;129(1):91-100.
Age-related macular degeneration (AMD) is a complex genetic disease, with many loci demonstrating appreciable attributable disease risk. Despite significant progress toward understanding the genetic and environmental etiology of AMD, identification of additional risk factors is necessary to fully appreciate and treat AMD pathology. In this study, we investigated copy number variants (CNVs) as potential AMD risk variants in a cohort of 400 AMD patients and 500 AMD-free controls ascertained at the University of Iowa. We used three publicly available copy number programs to analyze signal intensity data from Affymetrix® GeneChip SNP Microarrays. CNVs were ranked based on prevalence in the disease cohort and absence from the control group; high interest CNVs were subsequently confirmed by qPCR. While we did not observe a single-locus “risk CNV” that could account for a major fraction of AMD, we identified several rare and overlapping CNVs containing or flanking compelling candidate genes such as NPHP1 and EFEMP1. These and other candidate genes highlighted by this study deserve further scrutiny as sources of genetic risk for AMD.
doi:10.1007/s00439-010-0904-6
PMCID: PMC3613489  PMID: 20981449
7.  Parent-of-Origin Effects of the Serotonin Transporter Gene Associated with Autism 
A promoter-linked insertion/deletion polymorphism of the serotonin transporter gene (SLC6A4) has been implicated in autism spectrum disorders (ASDs) in numerous family-based association studies. However, the results of these investigations have been inconsistent in that both the long and short alleles have been shown to be over-transmitted to affected offspring. In order to further elucidate the relationship between the 5-HTTLPR variant and autism risk, we undertook a thorough study of parent-of-origin effects, maternal genotype effects, and offspring genotype effects in a sample of affected offspring from the Autism Genetic Resource Exchange (AGRE). Both the overall autism phenotype and measures of autism behaviors from the Autism Diagnostic Interview-Revised (Lord et al, 1994) were considered. We found evidence of over-transmission (risk allele short, p=0.012), maternal effects (risk allele long, p=0.035), and parent-of-origin effects (risk allele short from mother, p=0.018) of the 5-HTTLPR variant in the AGRE sample. Population-specific and gender-specific effects were also explored as associations may be heterogeneous across populations and sexes. Parent-of-origin effects of the variant were associated with maternally-inherited copies of the short allele that resulted in more impaired overall level of language (p=0.04). Our study was conducted to further investigate the 5-HTTLPR risk variants by identifying allelic associations that may be population-specific, phenotype-specific, or conferred by maternal or parent-of-origin effects. In light of conflicting observations from previous studies, these are just a few of the possible explanations that deserve attention.
doi:10.1002/ajmg.b.31146
PMCID: PMC3438509  PMID: 21302342
Autism; 5-HTTLPR; maternal effects; parent-of-origin effects; association
8.  Copy number variations on chromosome 12q14 in patients with normal tension glaucoma 
Human Molecular Genetics  2011;20(12):2482-2494.
We report identification of a novel genetic locus (GLC1P) for normal tension glaucoma (NTG) on chromosome 12q14 using linkage studies of an African-American pedigree (maximum non-parametric linkage score = 19.7, max LOD score = 2.7). Subsequent comparative genomic hybridization and quantitative polymerase chain reaction (PCR) experiments identified a 780 kbp duplication within the GLC1P locus that is co-inherited with NTG in the pedigree. Real-time PCR studies showed that the genes within this duplication [TBK1 (TANK-binding kinase 1), XPOT, RASSF3 and GNS] are all expressed in the human retina. Cohorts of 478 glaucoma patients (including 152 NTG patients), 100 normal control subjects and 400 age-related macular degeneration patients were subsequently tested for copy number variation in GLC1P. Overlapping duplications were detected in 2 (1.3%) of the 152 NTG subjects, one of which had a strong family history of glaucoma. These duplications defined a 300 kbp critical region of GLC1P that spans two genes (TBK1 and XPOT). Microarray expression experiments and northern blot analysis using RNA obtained from human skin fibroblast cells showed that duplication of chromosome 12q14 results in increased TBK1 and GNS transcription. Finally, immunohistochemistry studies showed that TBK1 is expressed in the ganglion cells, nerve fiber layer and microvasculature of the human retina. Together, these data link the duplication of genes on chromosome 12q14 with familial NTG and suggest that an extra copy of the encompassed TBK1 gene is likely responsible for these cases of glaucoma. However, animal studies will be necessary to rule out a role for the other duplicated or neighboring genes.
doi:10.1093/hmg/ddr123
PMCID: PMC3098731  PMID: 21447600
9.  Copy Number Variations and Primary Open-Angle Glaucoma 
This study has identified rare and recurrent deletions and duplications in POAG patients in the first large-scale, whole-genome study of structural variation performed in a sample of POAG patients and POAG-free subjects.
Purpose.
This study sought to investigate the role of rare copy number variation (CNV) in age-related disorders of blindness, with a focus on primary open-angle glaucoma (POAG). Data are reported from a whole-genome copy number screen in a large cohort of 400 individuals with POAG and 500 age-matched glaucoma-free subjects.
Methods.
DNA samples from patients and controls were tested for CNVs using a combination of two microarray platforms. The signal intensity data generated from these arrays were then analyzed with multiple CNV detection programs including CNAG version 2.0, PennCNV, and dChip.
Results.
A total of 11 validated CNVs were identified as recurrent in the POAG set and absent in the age-matched control set. This set included CNVs on 5q23.1 (DMXL1, DTWD2), 20p12 (PAK7), 12q14 (C12orf56, XPOT, TBK1, and RASSF3), 12p13.33 (TULP3), and 10q34.21 (PAX2), among others. The CNVs presented here are exceedingly rare and are not found in the Database of Genomic Variants. Moreover, expression data from ocular tissue support the role of these CNV-implicated genes in vision-related processes. In addition, CNV locations of DMXL1 and PAK7 overlap previously identified linkage signals for glaucoma on 5p23.1 and 20p12, respectively.
Conclusions.
The data are consistent with the hypothesis that rare CNV plays a role in the development of POAG.
doi:10.1167/iovs.10-5606
PMCID: PMC3207715  PMID: 21310917
10.  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.
doi:10.1038/nature07953
PMCID: PMC2925224  PMID: 19404257

Results 1-10 (10)