Rare mutations key to brain disorders

Many of the mutations that cause brain disorders are not inherited, new research on the genetics of mental retardation suggests, but are rare DNA variants that pop up for the first time in affected people.

A study published online November 14 in Nature Genetics highlights the importance of rare genetic variants in causing disease, and shows that disrupting even one copy of certain genes can have profound consequences for brain development and mental abilities, says James Lupski, a clinical geneticist at Baylor College of Medicine in Houston.