Deletions of <i>NRXN1</i> (neurexin‐1) predispose to a wide spectrum of developmental disorders

<jats:title>Abstract</jats:title><jats:p>Research has implicated mutations in the gene for neurexin‐1 (<jats:italic>NRXN1</jats:italic>) in a variety of conditions including autism, schizophrenia, and nicotine dependence. To our knowledge, there have been no published reports describing the breadth of the phenotype associated with mutations in <jats:italic>NRXN1</jats:italic>. We present a medical record review of subjects with deletions involving exonic sequences of <jats:italic>NRXN1</jats:italic>. We ascertained cases from 3,540 individuals referred clinically for comparative genomic hybridization testing from March 2007 to January 2009. Twelve subjects were identified with exonic deletions. The phenotype of individuals with <jats:italic>NRXN1</jats:italic> deletion is variable and includes autism spectrum disorders, mental retardation, language delays, and hypotonia. There was a statistically significant increase in <jats:italic>NRXN1</jats:italic> deletion in our clinical sample compared to control populations described in the literature (<jats:italic>P</jats:italic> = 8.9 × 10<jats:sup>−7</jats:sup>). Three additional subjects with <jats:italic>NRXN1</jats:italic> deletions and autism were identified through the Homozygosity Mapping Collaborative for Autism, and this deletion segregated with the phenotype. Our study indicates that deletions of <jats:italic>NRXN1</jats:italic> predispose to a wide spectrum of developmental disorders. © 2010 Wiley‐Liss, Inc.</jats:p>