CHROMOSOME FLAW LIKELY CAUSE OF SMALL PROPORTION OF AUTISM CASES

01/10/2008


The New England Journal of Medicine

Researchers have pinpointed a chromosomal abnormality believed to cause about one per cent of autism cases.  Deletion or duplication of the segment, which encompasses 25 known genes, was present in approximately 1% of case subjects and less than 0.1% of unscreened control subjects. 

Read the article here: Association between Microdeletion and Microduplication at 16p11.2 and Autism

Abstract

Background Autism spectrum disorder is a heritable developmental disorder in which chromosomal abnormalities are thought to play a role.

Methods As a first component of a genomewide association study of families from the Autism Genetic Resource Exchange (AGRE), we used two novel algorithms to search for recurrent copy-number variations in genotype data from 751 multiplex families with autism. Specific recurrent de novo events were further evaluated in clinical-testing data from Children's Hospital Boston and in a large population study in Iceland.

Results Among the AGRE families, we observed five instances of a de novo deletion of 593 kb on chromosome 16p11.2. Using comparative genomic hybridization, we observed the identical deletion in 5 of 512 children referred to Children's Hospital Boston for developmental delay, mental retardation, or suspected autism spectrum disorder, as well as in 3 of 299 persons with autism in an Icelandic population; the deletion was also carried by 2 of 18,834 unscreened Icelandic control subjects. The reciprocal duplication of this region occurred in 7 affected persons in AGRE families and 4 of the 512 children from Children's Hospital Boston. The duplication also appeared to be a high-penetrance risk factor.

Conclusions We have identified a novel, recurrent microdeletion and a reciprocal microduplication that carry substantial susceptibility to autism and appear to account for approximately 1% of cases. We did not identify other regions with similar aggregations of large de novo mutations.