Copy-number variation in BMPR2 is not associated with the pathogenesis of pulmonary arterial hypertension

<p>Abstract</p> <p>Background</p> <p>Copy-number variations (CNVs) are structural variations in the genome involving 1 kb to 3 mb of DNA. CNV has been reported within intron 1 of the <it>BMPR2 </it>gene. We propose that CNV could affect phenotype in familial and/or sporadic pulmonary arterial hypertension (PAH) by altering gene expression.</p> <p>Methods</p> <p>97 human DNA samples were obtained which included 24 patients with familial PAH, 18 obligate carriers (<it>BMPR2 </it>mutation positive), 20 sporadic PAH patients, and 35 controls. Two sets of primers were designed within the CNV, and two sets of control primers were designed outside the CNV. Quantitative PCR was performed to quantify genomic copies of CNV and control sequences.</p> <p>Results</p> <p>A CNV in <it>BMPR2 </it>was present in one African American negative control subject.</p> <p>Conclusion</p> <p>We conclude that the CNV in intron 1 in <it>BMPR2 </it>is unlikely to play a role in the pathogenesis of either familial or sporadic PAH.</p> <p>Trial Registration</p> <p>NIH NCT00091546.</p

Modeling rare gene variation to gain insight into the oldest biomarker in autism: construction of the serotonin transporter Gly56Ala knock-in mouse

Alterations in peripheral and central indices of serotonin (5-hydroxytryptamine, 5-HT) production, storage and signaling have long been associated with autism. The 5-HT transporter gene (HTT, SERT, SLC6A4) has received considerable attention as a potential risk locus for autism-spectrum disorders, as well as disorders with overlapping symptoms, including obsessive-compulsive disorder (OCD). Here, we review our efforts to characterize rare, nonsynonymous polymorphisms in SERT derived from multiplex pedigrees carrying diagnoses of autism and OCD and present the initial stages of our effort to model one of these variants, Gly56Ala, in vivo. We generated a targeting vector to produce the Gly56Ala substitution in the Slc6a4 locus by homologous recombination. Following removal of a neomycin resistance selection cassette, animals exhibiting germline transmission of the Ala56 variant were bred to establish a breeding colony on a 129S6 background, suitable for initial evaluation of biochemical, physiological and behavioral alterations relative to SERT Gly56 (wildtype) animals. SERT Ala56 mice were achieved and exhibit a normal pattern of transmission. The initial growth and gross morphology of these animals is comparable to wildtype littermate controls. The SERT Ala56 variant can be propagated in 129S6 mice without apparent disruption of fertility and growth. We discuss both the opportunities and challenges that await the physiological/behavioral analysis of Gly56Ala transgenic mice, with particular reference to modeling autism-associated traits

Autism as a disorder of neural information processing: directions for research and targets for therapy

The broad variation in phenotypes and severities within autism spectrum disorders suggests the involvement of multiple predisposing factors, interacting in complex ways with normal developmental courses and gradients. Identification of these factors, and the common developmental path into which theyfeed, is hampered bythe large degrees of convergence from causal factors to altered brain development, and divergence from abnormal brain development into altered cognition and behaviour. Genetic, neurochemical, neuroimaging and behavioural findings on autism, as well as studies of normal development and of genetic syndromes that share symptoms with autism, offer hypotheses as to the nature of causal factors and their possible effects on the structure and dynamics of neural systems. Such alterations in neural properties may in turn perturb activity-dependent development, giving rise to a complex behavioural syndrome many steps removed from the root causes. Animal models based on genetic, neurochemical, neurophysiological, and behavioural manipulations offer the possibility of exploring these developmental processes in detail, as do human studies addressing endophenotypes beyond the diagnosis itself

Profiling allele-specific gene expression in brains from individuals with autism spectrum disorder reveals preferential minor allele usage.

One fundamental but understudied mechanism of gene regulation in disease is allele-specific expression (ASE), the preferential expression of one allele. We leveraged RNA-sequencing data from human brain to assess ASE in autism spectrum disorder (ASD). When ASE is observed in ASD, the allele with lower population frequency (minor allele) is preferentially more highly expressed than the major allele, opposite to the canonical pattern. Importantly, genes showing ASE in ASD are enriched in those downregulated in ASD postmortem brains and in genes harboring de novo mutations in ASD. Two regions, 14q32 and 15q11, containing all known orphan C/D box small nucleolar RNAs (snoRNAs), are particularly enriched in shifts to higher minor allele expression. We demonstrate that this allele shifting enhances snoRNA-targeted splicing changes in ASD-related target genes in idiopathic ASD and 15q11-q13 duplication syndrome. Together, these results implicate allelic imbalance and dysregulation of orphan C/D box snoRNAs in ASD pathogenesis

Homozygous microdeletion of exon 5 in ZNF277 in a girl with specific language impairment

Peer reviewedPublisher PD

Angelman syndrome: advancing the research frontier of neurodevelopmental disorders

This report is a meeting summary of the 2010 Angelman Syndrome Foundation's scientific symposium on the neuroscience of UBE3A. Angelman syndrome is characterized by loss of speech, severe developmental delay, seizures, and ataxia. These core symptoms are caused by maternal allele disruptions of a single gene—UBE3A. UBE3A encodes an E3 ubiquitin ligase that targets certain proteins for proteasomal degradation. This biology has led to the expectation that the identification of Ube3a protein targets will lead to therapies for Angelman syndrome. The recent discovery of Ube3a substrates such as Arc (activity-regulated cytoskeletal protein) provides new insight into the mechanisms underlying the synaptic function and plasticity deficits caused by the loss of Ube3a. In addition to identifying Ube3a substrates, there have also been recent advances in understanding UBE3A's integrated role in the neuronal repertoire of genes and protein interactions. A developmental picture is now emerging whereby UBE3A gene dosage on chromosome 15 alters synaptic function, with deficiencies leading to Angelman syndrome and overexpression associated with classic autism symptomatology