Posts By: Yannis Trakadis

Do all nerve cells of an individual have the same genome?

Posted by & filed under Part 28: NEUROGENETICS.

As individuals grow older, human neurons appear to diversify (e.g. aneuploid neurons or subchromosomal CNVs in euploid neurons). McConnell et al recently published in Science that mosaic copy number variation (CNV) is abundant in human neurons.   McConnell et al used single-cell genomic approaches to map DNA in neurons obtained from human induced pluripotent stem […]

shared genetic etiology for different psychiatric disorders

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To examine shared genetic etiology among different psychiatric disorders Lee et al. used genome-wide genotype data (from the Psychiatric Genomics Consortium) for cases and controls in schizophrenia, bipolar disorder, major depressive disorder, autism spectrum disorders (ASD) and attention-deficit/hyperactivity disorder (ADHD). After univariate and bivariate analysis, the genetic variation within and covariation between disorders was estimated. […]

Actionable Incidental Findings in 1,000 Participants’ Exomes

Posted by & filed under Exome sequencing, Treatment.

Dorschner et al. estimated the number of expected actionable findings in a cohort of 1,000 participants randomly selected from the National Heart, Lung, and Blood Institute Exome Sequencing Project (500 European; 500 African-descent individuals). The participants were screened for variants in 114 genes pre-selected by an expert panel for their association with medically actionable genetic […]

PKU-BH4 responders and executive function/ white matter changes

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Blood blood phenylalanine (Phe), microstructural white matter integrity (evaluated by mean diffusivity from diffusion tensor imaging), and executive abilities were assessed in 12 PKU patients, known BH4 responders. Assessments were performed before initiation of treatment with BH4 (baseline) and repeated six months later (follow-up). Compared with baseline, Phe decreased by 51% during over four weeks […]

Neurocognitive functioning in adults with PKU

Posted by & filed under Part 08: AMINO ACIDS, Treatment.

Weglage et al. investigated 57 adult patients with early-treated classical PKU (mean age 31 years) and 46 healthy controls, matched for age and socioeconomic status. MRI brain and evaluation for IQ, as well as for attention and information-processing were performed in all patients and controls. Neuropsychological assessments and MRI were repeated at a five-year-follow up. Over […]

Archived neonatal dried blood spot samples for accurate whole genome sequencing

Posted by & filed under Exome sequencing, Newborn screening, Part 06: DIAGNOSTIC APPROACHES.

Hollegaard et al. have demonstrated in the past that DNA extracted from a fraction (2 × 3.2 mm discs) of an archived Dried blood spot sample (DBSS) can be whole genome amplified (wgaDNA) and used for accurate array genotyping. In this study, they compared whole-blood DNA next-generation sequencing (NGS) results to results from DBSS and concluded that DBSS […]

Supreme Court rules out patents on ‘natural’ genes

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The U.S. Supreme Court ruled on June 13th, 2013 that Myriad “found an important and useful gene, but separating that gene from its surrounding genetic material is not an act of invention.” Raw DNA sequences, even if “isolated” from tissue, are a “product of nature”  and thus are not patentable. The court also ruled that […]

16p11.2 deletion and autism

Posted by & filed under Part 28: NEUROGENETICS, _.

The recurrent ~600 kb 16p11.2 deletion, defined by breakpoints 4 and 5 (BP4-BP5), is among the most frequent known genetic aetiologies of autism spectrum disorder (ASD). Its population prevalence is ~ 1/2000, but in ASD it reaches 1/200. Zufferey et al collected clinical data on 285 deletion carriers and performed detailed evaluations on 72 carriers […]

MTTP allele as a risk factor for metabolic syndrome with atypical antipsychotics

Posted by & filed under Part 28: NEUROGENETICS, Treatment.

Liou et al. recently published a study illustrating that promoter polymorphisms in microsomal triglyceride transfer protein (MTTP) are associated with metabolic syndrome in schizophrenic patients treated with atypical antipsychotics. 456 hospitalized patients with schizophrenia, who had been treated with clozapine (n = 171), olanzapine (n = 91), or risperidone (n = 194) for at least […]

Sturge–Weber Syndrome – GNAQ Somatic Mutation

Posted by & filed under Part 28: NEUROGENETICS.

The Sturge–Weber syndrome and port-wine stains are caused by a somatic activating mutation in GNAQ. Whole-genome sequencing of DNA from paired samples of visibly affected and normal tissue from 3 persons with the Sturge–Weber syndrome was performed.  A non-synonymous single-nucleotide variant (c.548G?A, p.Arg183Gln) was identified in GNAQ in samples of affected tissue from 88% of […]