Association of brain-derived neurotrophic factor (BDNF) haploinsufficiency with lower adaptive behaviour and reduced cognitive functioning in WAGR/11p13 deletion syndrome.

In animal studies, brain-derived neurotrophic factor (BDNF) is an important regulator of central nervous system development and synaptic plasticity. WAGR (Wilms tumour, Aniridia, Genitourinary anomalies, and mental Retardation) syndrome is caused by 11p13 deletions of variable size near the BDNF locus and can serve as a model for studying human BDNF haploinsufficiency (+/-). We hypothesized that BDNF+/- would be associated with more severe cognitive impairment in subjects with WAGR syndrome. Twenty-eight subjects with WAGR syndrome (6-28 years), 12 subjects with isolated aniridia due to PAX6 mutations/microdeletions (7-54 years), and 20 healthy controls (4-32 years) received neurocognitive assessments. Deletion boundaries for the subjects in the WAGR group were determined by high-resolution oligonucleotide array comparative genomic hybridization. Within the WAGR group, BDNF+/- subjects (n = 15), compared with BDNF intact (+/+) subjects (n = 13), had lower adaptive behaviour (p = .02), reduced cognitive functioning (p = .04), higher levels of reported historical (p = .02) and current (p = .02) social impairment, and higher percentage meeting cut-off score for autism (p = .047) on Autism Diagnostic Interview-Revised. These differences remained nominally significant after adjusting for visual acuity. Using diagnostic measures and clinical judgement, 3 subjects (2 BDNF+/- and 1 BDNF+/+) in the WAGR group (10.7%) were classified with autism spectrum disorder. A comparison group of visually impaired subjects with isolated aniridia had cognitive functioning comparable to that of healthy controls. In summary, among subjects with WAGR syndrome, BDNF+/- subjects had a mean Vineland Adaptive Behaviour Compose score that was 14-points lower and a mean intelligence quotient (IQ) that was 20-points lower than BDNF+/+ subjects. Our findings support the hypothesis that BDNF plays an important role in human neurocognitive development.

Integrative gene network analysis provides novel regulatory relationships, genetic contributions and susceptible targets in autism spectrum disorders.

Autism spectrum disorders (ASDs) are a group of diseases exhibiting impairment in social drive, communication/language skills and stereotyped behaviors. Though an increased number of candidate genes and molecular interactions have been identified by various approaches, the pathogenesis remains elusive. Based on clinical observations, data from accessible GWAS and expression datasets we identified ASDs gene candidates. Integrative gene network and a novel CNV-centric Node Network (CNN) analysis method highlighted ASDs-associated key elements and biological processes. Functional analysis identified neurological functions including synaptic cholinergic receptor (CHRNA) families, dopamine receptor (DRD2), and correlations between social behavior and oxytocin related pathways. CNN analysis of genome-wide genetic and expression data identified inheritance-related clusters related to PTEN/TSC1/FMR1 and mTor/PI3K regulation. Integrative analysis identified potential regulators of networks, specifically TNF and beta-estradiol, suggesting a potential central role in ASDs. Our data provide information on potential disease mechanisms, and key regulators that may generate novel postulations, and diagnostic molecular biomarkers.

A woman with spontaneous premature ovarian failure gives birth to a child with fragile X syndrome.

OBJECTIVE: To inform clinicians about a reproductive risk associated with spontaneous premature ovarian failure and the fragile X mental retardation 1 gene (FMR1). DESIGN: Case report. SETTING: National Institutes of Health Clinical Center. PATIENT(S): A 35-year-old woman with confirmed spontaneous premature ovarian failure. INTERVENTION(S): FMR1 genetic testing. MAIN OUTCOME MEASURE(S): Number of CGG trinucleotide repeats in the 5' untranslated region of FMR1. RESULT(S): Despite having ovarian failure the woman subsequently conceived and delivered a son with fragile X syndrome (>200 CGG repeats). She was then found to carry an FMR1 premutation (85 CGG repeats). CONCLUSION(S): This is a real-life manifestation of a theoretical risk; a woman conceived subsequent to the diagnosis of spontaneous premature ovarian failure and has a child who manifests mental retardation due to fragile X syndrome. Women with spontaneous premature ovarian failure are at increased risk of having an FMR1 premutation and should be informed of the availability of fragile X testing. Should an FMR1 premutation be uncovered, this will allow patients to make informed reproductive decisions and help clinicians to properly diagnose family members who may have menstrual irregularity, developmental delay, or neurologic symptoms.