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Whole-genome sequencing in a family with twin boys with autism and intellectual disability suggests multimodal polygenic risk
Journal article   Open access   Peer reviewed

Whole-genome sequencing in a family with twin boys with autism and intellectual disability suggests multimodal polygenic risk

Brooke McKenna, Tanner Koomar, Kevin Vervier, Jamie Kremsreiter and Jacob J Michaelson
Cold Spring Harbor molecular case studies, Vol.4(6), p.a003285
12/2018
DOI: 10.1101/mcs.a003285
PMCID: PMC6318775
PMID: 30559312
url
https://doi.org/10.1101/mcs.a003285View
Published (Version of record) Open Access

Abstract

Over the past decade, a focus on de novo mutations has rapidly accelerated gene discovery in autism spectrum disorder (ASD), intellectual disability (ID), and other neurodevelopmental disorders (NDDs). However, recent studies suggest that only a minority of cases are attributable to de novo mutations, and instead these disorders often result from an accumulation of various forms of genetic risk. Consequently, we adopted an inclusive approach to investigate the genetic risk contributing to a case of male monozygotic twins with ASD and ID. At the time of the study, the probands were 7 yr old and largely nonverbal. Medical records indicated a history of motor delays, sleep difficulties, and significant cognitive deficits. Through whole-genome sequencing of the probands and their parents, we uncovered elevated common polygenic risk, a coding de novo point mutation in , an ultra-rare homozygous regulatory variant in , inherited rare variants in , and a maternally inherited X-linked deletion situated in a noncoding regulatory region between and Although each of these genes has been directly or indirectly associated with NDDs, evidence suggests that no single variant adequately explains the probands' phenotype. Instead, we propose that the probands' condition is due to the confluence of multiple rare variants in the context of a high-risk genetic background. This case emphasizes the multifactorial nature of genetic risk underlying most instances of NDDs and aligns with the "female protective model" of ASD.
Phenotype Family Mutation Autistic Disorder - genetics Autism Spectrum Disorder - genetics Multifactorial Inheritance - genetics Genetic Predisposition to Disease - genetics Humans Risk Factors Male Neurodevelopmental Disorders - genetics Whole Genome Sequencing - methods Twins, Monozygotic Nerve Tissue Proteins - genetics Chromosomal Proteins, Non-Histone - genetics Intellectual Disability - genetics Genes, X-Linked Ankyrins - genetics Adult Female Child

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