Title

Haploinsufficiency of the Notch Ligand DLL1 Causes Variable Neurodevelopmental Disorders.

Document Type

Article

Publication Date

9-5-2019

Identifier

DOI: 10.1016/j.ajhg.2019.07.002; PMCID: PMC6731356

Abstract

Notch signaling is an established developmental pathway for brain morphogenesis. Given that Delta-like 1 (DLL1) is a ligand for the Notch receptor and that a few individuals with developmental delay, intellectual disability, and brain malformations have microdeletions encompassing DLL1, we hypothesized that insufficiency of DLL1 causes a human neurodevelopmental disorder. We performed exome sequencing in individuals with neurodevelopmental disorders. The cohort was identified using known Matchmaker Exchange nodes such as GeneMatcher. This method identified 15 individuals from 12 unrelated families with heterozygous pathogenic DLL1 variants (nonsense, missense, splice site, and one whole gene deletion). The most common features in our cohort were intellectual disability, autism spectrum disorder, seizures, variable brain malformations, muscular hypotonia, and scoliosis. We did not identify an obvious genotype-phenotype correlation. Analysis of one splice site variant showed an in-frame insertion of 12 bp. In conclusion, heterozygous DLL1 pathogenic variants cause a variable neurodevelopmental phenotype and multi-systemic features. The clinical and molecular data support haploinsufficiency as a mechanism for the pathogenesis of this DLL1-related disorder and affirm the importance of DLL1 in human brain development.

Journal Title

American journal of human genetics

Volume

105

Issue

3

First Page

631

Last Page

639

MeSH Keywords

Calcium-Binding Proteins; Cohort Studies; Female; Haploinsufficiency; Humans; Ligands; Male; Membrane Proteins; Neurodevelopmental Disorders; Pedigree; Whole Exome Sequencing

Keywords

DLL1; Notch signaling; autism; brain malformation; developmental delay; intellectual disability; vertebral segmentation defects

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