The corpus callosum is the principal cerebral commissure connecting the right and left hemispheres. The development of the corpus callosum is under tight genetic control, as demonstrated by abnormalities in its development in more than 1,000 genetic syndromes. We recruited more than 25 families in which members affected with corpus callosum hypoplasia (CCH) lacked syndromic features and had consanguineous parents, suggesting recessive causes. Exome sequence analysis identified C12orf57 mutations at the initiator methionine codon in four different families. C12orf57 is ubiquitously expressed and encodes a poorly annotated 126 amino acid protein of unknown function. This protein is without significant paralogs but has been tightly conserved across evolution. Our data suggest that this conserved gene is required for development of the human corpus callosum.
BackgroundIn children with sensory processing dysfunction (SPD), who do not meet criteria for autism spectrum disorder (ASD) or intellectual disability, the contribution of de novo pathogenic mutation in neurodevelopmental genes is unknown and in need of investigation. We hypothesize that children with SPD may have pathogenic variants in genes that have been identified as causing other neurodevelopmental disorders including ASD. This genetic information may provide important insight into the etiology of sensory processing dysfunction and guide clinical evaluation and care.MethodsEleven community-recruited trios (children with isolated SPD and both biological parents) underwent WES to identify candidate de novo variants and inherited rare single nucleotide variants (rSNV) in genes previously associated with ASD. Gene enrichment in these children and their parents for transmitted and non-transmitted mutation burden was calculated. A comparison analysis to assess for enriched rSNV burden was then performed in 2377 children with ASD and their families from the Simons Simplex Collection.ResultsOf the children with SPD, 2/11 (18%), were identified as having a de novo loss of function or missense mutation in genes previously reported as causative for neurodevelopmental disorders (MBD5 and FMN2). We also found that the parents of children with SPD have significant enrichment of pathogenic rSNV burden in high-risk ASD candidate genes that are inherited by their affected children. Using the same approach, we confirmed enrichment of rSNV burden in a large cohort of children with autism and their parents but not unaffected siblings.ConclusionsOur findings suggest that SPD, like autism, has a genetic basis that includes both de novo single gene mutations as well as an accumulated burden of rare inherited variants from their parents.Electronic supplementary materialThe online version of this article (10.1186/s12920-018-0362-x) contains supplementary material, which is available to authorized users.
Background
The contribution of pathogenic gene variants with development of epilepsy after acute symptomatic neonatal seizures is not known.
Methods
Case–control study of 20 trios in children with a history of acute symptomatic neonatal seizures: 10 with and 10 without post-neonatal epilepsy. We performed whole-exome sequencing (WES) and identified pathogenic de novo, transmitted, and non-transmitted variants from established and candidate epilepsy association genes and correlated prevalence of these variants with epilepsy outcomes. We performed a sensitivity analysis with genes associated with coronary artery disease (CAD). We analyzed variants throughout the exome to evaluate for differential enrichment of functional properties using exploratory KEGG searches.
Results
Querying 200 established and candidate epilepsy genes, pathogenic variants were identified in 5 children with post-neonatal epilepsy yet in only 1 child without subsequent epilepsy. There was no difference in the number of trios with non-transmitted pathogenic variants in epilepsy or CAD genes. An exploratory KEGG analysis demonstrated a relative enrichment in cell death pathways in children without subsequent epilepsy.
Conclusions
In this pilot study, children with epilepsy after acute symptomatic neonatal seizures had a higher prevalence of coding variants with a targeted epilepsy gene sequencing analysis compared to those patients without subsequent epilepsy.
Impact
We performed whole-exome sequencing (WES) in 20 trios, including 10 children with epilepsy and 10 without epilepsy, both after acute symptomatic neonatal seizures.
Children with post-neonatal epilepsy had a higher burden of pathogenic variants in epilepsy-associated genes compared to those without post-neonatal epilepsy.
Future studies evaluating this association may lead to a better understanding of the risk of epilepsy after acute symptomatic neonatal seizures and elucidate molecular pathways that are dysregulated after brain injury and implicated in epileptogenesis.
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