Array CGH identifies reciprocal 16p13.1 duplications and deletions that predispose to autism and/or mental retardation

Autism and mental retardation (MR) are often associated, suggesting that these conditions are etiologically related. Recently, array‐based comparative genomic hybridization (array CGH) has identified submicroscopic deletions and duplications as a common cause of MR, prompting us to search for such genomic imbalances in autism. Here we describe a 1.5‐Mb duplication on chromosome 16p13.1 that was found by high‐resolution array CGH in four severe autistic male patients from three unrelated families. The same duplication was identified in several variably affected and unaffected relatives. A deletion of the same interval was detected in three unrelated patients with MR and other clinical abnormalities. In one patient we revealed a further rearrangement of the 16p13 imbalance that was not present in his unaffected mother. Duplications and deletions of this 1.5‐Mb interval have not been described as copy number variants in the Database of Genomic Variants and have not been identified in >600 individuals from other cohorts examined by high‐resolution array CGH in our laboratory. Thus we conclude that these aberrations represent recurrent genomic imbalances which predispose to autism and/or MR. Hum Mutat 28(7), 674–682, 2007. © 2007 Wiley‐Liss, Inc.