Copy number variants (CNVs) are associated with many neurocognitive disorders; however, these events are typically large and the underlying causative gene is unclear. We created an expanded CNV morbidity map from 29,085 children with developmental delay versus 19,584 healthy controls, identifying 70 significant CNVs. We resequenced 26 candidate genes in 4,716 additional cases with developmental delay or autism and 2,193 controls. An integrated analysis of CNV and single-nucleotide variant (SNV) data pinpointed ten genes enriched for putative loss of function. Patient follow-up on a subset identified new clinical subtypes of pediatric disease and the genes responsible for disease-associated CNVs. This includes haploinsufficiency of SETBP1 associated with intellectual disability and loss of expressive language and truncations of ZMYND11 in patients with autism, aggression and complex neuropsychiatric features. This combined CNV and SNV approach facilitates the rapid discovery of new syndromes and neuropsychiatric disease genes despite extensive genetic heterogeneity.

Vici syndrome is a progressive neurodevelopmental multisystem disorder caused by mutations in the autophagy gene EPG5. Byrne et al. characterise the phenotype of 50 affected children, revealing callosal agenesis, cataracts, hypopigmentation, cardiomyopathy, immune dysfunction, developmental delay and microcephaly. Downregulation of epg5 in Drosophila results in autophagic abnormalities and progressive neurodegeneration.