Common polygenic variation contributes to risk of schizophrenia and bipolar disorder.

Schizophrenia is a severe mental disorder with a lifetime risk of about 1%, characterized by hallucinations, delusions and cognitive deficits, with heritability estimated at up to 80%. We performed a genome-wide association study of 3,322 European individuals with schizophrenia and 3,587 controls. Here we show, using two analytic approaches, the extent to which common genetic variation underlies the risk of schizophrenia. First, we implicate the major histocompatibility complex. Second, we provide molecular genetic evidence for a substantial polygenic component to the risk of schizophrenia involving thousands of common alleles of very small effect. We show that this component also contributes to the risk of bipolar disorder, but not to several non-psychiatric diseases.

DNA double-strand breaks relieve USF-mediated repression of Dß2 germline transcription in developing thymocytes.

Activation of germline promoters is central to V(D)J recombinational accessibility, driving chromatin remodeling, nucleosome repositioning, and transcriptional read-through of associated DNA. We have previously shown that of the two TCRß locus (Tcrb) D segments, Dß1 is flanked by an upstream promoter that directs its transcription and recombinational accessibility. In contrast, transcription within the DJß2 segment cluster is initially restricted to the J segments and only redirected upstream of Dß2 after D-to-J joining. The repression of upstream promoter activity prior to Tcrb assembly correlates with evidence that suggests DJß2 recombination is less efficient than that of DJß1. Because inefficient DJß2 assembly offers the potential for V-to-DJß2 recombination to rescue frameshifted V-to-DJß1 joints, we wished to determine how Dß2 promoter activity is modulated upon Tcrb recombination. In this study, we show that repression of the otherwise transcriptionally primed 5'Dß2 promoter requires binding of upstream stimulatory factor (USF)-1 to a noncanonical E-box within the Dß2 12-recombination signal sequence spacer prior to Tcrb recombination. USF binding is lost from both rearranged and germline Dß2 sites in DNA-dependent protein kinase, catalytic subunit-competent thymocytes. Finally, genotoxic dsDNA breaks lead to rapid loss of USF binding and gain of transcriptionally primed 5'Dß2 promoter activity in a DNA-dependent protein kinase, catalytic subunit-dependent manner. Together, these data suggest a mechanism by which V(D)J recombination may feed back to regulate local Dß2 recombinational accessibility during thymocyte development.

Copy number variations on chromosome 12q14 in patients with normal tension glaucoma.

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.

Linkage, association, and gene-expression analyses identify CNTNAP2 as an autism-susceptibility gene.

Autism is a genetically complex neurodevelopmental syndrome in which language deficits are a core feature. We describe results from two complimentary approaches used to identify risk variants on chromosome 7 that likely contribute to the etiology of autism. A two-stage association study tested 2758 SNPs across a 10 Mb 7q35 language-related autism QTL in AGRE (Autism Genetic Resource Exchange) trios and found significant association with Contactin Associated Protein-Like 2 (CNTNAP2), a strong a priori candidate. Male-only containing families were identified as primarily responsible for this association signal, consistent with the strong male affection bias in ASD and other language-based disorders. Gene-expression analyses in developing human brain further identified CNTNAP2 as enriched in circuits important for language development. Together, these results provide convergent evidence for involvement of CNTNAP2, a Neurexin family member, in autism, and demonstrate a connection between genetic risk for autism and specific brain structures.

The relationship between glaucoma medication adherence, eye drop technique, and visual field defect severity.

OBJECTIVE: The purpose of the study was to examine (1) how patient adherence and eye drop technique were associated with visual field defect severity and (2) how general glaucoma adherence self-efficacy and eye drop technique self-efficacy were related to visual field defect severity. DESIGN: Cross-sectional study conducted at a single private practice site. PARTICIPANTS: Patients using eye drops for their glaucoma. METHODS: Subject adherence to glaucoma medications through Medication Events Monitoring System (MEMS) devices were measured, and eye drop instillation technique was assessed by video recording. General glaucoma medication adherence self-efficacy was measured using a 10-item scale, and eye drop technique self-efficacy was measured using a 6-item scale. Multivariate logistic regression was used to analyze the data. MAIN OUTCOME MEASURES: Visual field defect severity. RESULTS: Patients who were less than 80% adherent according to the MEMS devices were significantly more likely to have worse defect severity. Patients with lower scores on the general glaucoma medication adherence self-efficacy scale also were significantly more likely to have worse defect severity. Eye drop technique and eye drop technique self-efficacy were not related significantly to visual field defect severity. CONCLUSIONS: Eye care providers need to assess patient adherence and to work with those patients with poor adherence to find ways to improve their ability and self-efficacy in using their glaucoma medications. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found after the references.

Validation of a short version of the glaucoma medication self-efficacy questionnaire.

AIMS: The aims of this study were: (1) to examine whether the original glaucoma medication adherence and eye drop technique self-efficacy scales could be shortened for easier use in practice settings; and (2) to validate these scales against objective medication adherence measures. METHODS: Prospective study conducted at a single private practice site. We measured subjects' adherence to glaucoma medications through Medication Event Monitoring System (MEMS) devices and assessed eye drop instillation technique by video-recording. Principal components factor analysis and logistic and linear regression were used to analyse the data. RESULTS: Our results yielded a 10-item Glaucoma Medication Adherence Self-Efficacy Scale that was strongly associated with subject adherence measured using MEMS (ß coefficient 8.52, 95% CI 1.94 to 15.1). In addition, the six-item Eye Drop Technique Self-Efficacy Scale was strongly associated with video-recorded subject eye drop installation technique (OR 10.47, 95% CI 1.78 to 61.63). CONCLUSIONS: Eye care providers and researchers could use these shorter scales to identify subjects with either poor glaucoma medication adherence and/or eye drop instillation technique. This could help to identify those who may benefit most from education and training on both adherence and eye drop instillation.

An objective evaluation of eyedrop instillation in patients with glaucoma.

OBJECTIVES: To evaluate the performance of patients with ocular hypertension and glaucoma who are experienced in the instillation of topical ocular hypotensive medications. METHODS: We conducted a prospective, open-label study at a single private practice site. We enrolled 139 patients with a diagnosis of glaucoma or ocular hypertension who used 1 or more topical ocular hypotensive medications for at least 6 months and who instilled their own medications. Patients were questioned regarding their use of topical ocular hypotensive medications, and we used a video recording to evaluate patient performance of eyedrop instillation with 2 bottle designs. RESULTS: Patients reported relatively good performance on eyedrop instillation. One hundred twenty-nine of 139 patients (92.8%) reported no problem putting in their eyedrops, and 86 of 139 (61.9%) believed that they never missed their eye when administering the drops. The proportions of patients who were able to instill a single drop into the eye without touching the bottle to the eye were 14 of 64 (21.9%) with a 15-mL bottle and 36 of 117 (30.8%) with a 2.5-mL bottle. CONCLUSIONS: Under a single direct observation, patients experienced in the use of topical ocular hypotensive agents performed relatively poorly when instilling a single eyedrop into the eye without touching the bottle tip to the eye or the ocular adnexae. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00522600.

High density SNP association study of a major autism linkage region on chromosome 17.

A region on chromosome 17 has recently been highlighted as linked to autism (MIM[209850]) in multiple studies and evidence has accumulated suggesting that male-only families (those families that have produced only affected males) provide the major contribution to linkage at this locus. In an attempt to comprehensively test for association of common variants to autism within the region on chromosome 17 defined in Stone et al. (Stone, J.L., Merriman, B., Cantor, R.M., Yonan, A.L., Gilliam, T.C., Geschwind, D.H. and Nelson, S.F. (2004) Evidence for sex-specific risk alleles in autism spectrum disorder. Am. J. Hum. Genet., 75, 1117-1123), a dense panel of single nucleotide polymorphisms (SNPs) was selected across the linkage peak and analyzed in a trio-based study design. SNPs were genotyped in 219 independent trios at an average intermarker distance of 6.1 kb across the 13.7 Mb interval. This provided ~80% coverage of common HapMap variation present in Caucasians, testing exonic, intronic, promoter and intergenic regions, as knowledge of important functional regions within the genome is currently limited. In this comprehensive association study of a linkage region in autism, no single SNP or haplotype association was sufficient to account for the initial linkage signal. Nominally significant single SNP and/or haplotype-based association results were detected in 15 genes, of which, MYO1D, ACCN1 and LASP1 stand out as genes with autism risk alleles requiring further study, with potential GRRs in the range of 1.34-2.29.

Replication of autism linkage: fine-mapping peak at 17q21.

Autism is a heritable but genetically complex disorder characterized by deficits in language and in reciprocal social interactions, combined with repetitive and stereotypic behaviors. As with many genetically complex disorders, numerous genome scans reveal inconsistent results. A genome scan of 345 families from the Autism Genetic Resource Exchange (AGRE) (AGRE_1), gave the strongest evidence of linkage at 17q11-17q21 in families with no affected females. Here, we report a full-genome scan of an independent sample of 91 AGRE families with 109 affected sibling pairs (AGRE_2) that also shows the strongest evidence of linkage to 17q11-17q21 in families with no affected females. Taken together, these samples provide a replication of linkage to this chromosome region that is, to our knowledge, the first such replication in autism. Fine mapping at 2-centimorgan (cM) intervals in the combined sample of families with no affected females reveals a linkage peak at 66.85 cM, which places this locus at 17q21.

Evidence for sex-specific risk alleles in autism spectrum disorder.

We investigated the genetic aspects of the large sex bias in the prevalence of autism spectrum disorder by monitoring changes in linkage when the family set for an affected sibling pair genome scan is subdivided on the basis of the sex of affected children. This produces a significant excess in the total number of linkage peaks (P=1.3 x 10(-8)) and identifies a major male-specific linkage peak at chromosome 17q11 (P<.01). These results suggest that sexual dichotomy is an important factor in the genetics of autism; the same strategy can be used to explore this possibility in other complex disorders that exhibit significant sex biases.

Genetic linkage of attention-deficit/hyperactivity disorder on chromosome 16p13, in a region implicated in autism.

Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed behavioral disorder in childhood and likely represents an extreme of normal behavior. ADHD significantly impacts learning in school-age children and leads to impaired functioning throughout the life span. There is strong evidence for a genetic etiology of the disorder, although putative alleles, principally in dopamine-related pathways suggested by candidate-gene studies, have very small effect sizes. We use affected-sib-pair analysis in 203 families to localize the first major susceptibility locus for ADHD to a 12-cM region on chromosome 16p13 (maximum LOD score 4.2; P=.000005), building upon an earlier genomewide scan of this disorder. The region overlaps that highlighted in three genome scans for autism, a disorder in which inattention and hyperactivity are common, and physically maps to a 7-Mb region on 16p13. These findings suggest that variations in a gene on 16p13 may contribute to common deficits found in both ADHD and autism.