Over the past couple of years, study after study has found specific DNA deletions and duplications, called copy number variations (CNVs), that independently increase an individual's risk of autism.But what if you carry more than one CNV?A study published online 14 February in Nature Genetics is among the first to focus on the combined risk of having multiple CNVs for psychiatric disease.Screening more than 20,000 children with intellectual disability,Evan Eichler and an international group of colleagues found a deletion on chromosomal region 16p12.1 in 42 individuals, or about 0.2 percent — about four times the frequency they saw in the healthy control population.In addition to developmental delay, children who carry the 16p12.1 deletion may also have congenital heart defects, seizures and severe growth abnormalities, the researchers found. The deletion joins three others on the short arm of chromosome 16 that are associated with autism or other neurodevelopmental disorders.Read more at...SFARI, March 2010.