Recently, it was reported that some patients with both autism and macrocephaly have mutations in the PTEN tumor suppressor gene. PTEN is a lipid phosphatase that regulates cell survival and proliferation. It also plays a critical role during development, influencing neural stem cells as well as immature and mature neurons. While previous studies have reported an interesting association with PTEN mutations and autism, Dr. Ross's lab will expand the investigations into this genetic mutation by determining whether specific PTEN mutations eliminate the expression of PTEN or reduce its stability. Significance: Understanding the genetic and biochemical bases of autism is one of the first steps to better diagnosis and therapy. This study is also intriguing since many drugs that affect PTEN signaling pathway are already available given the gene's known role in cancer, and could potentially be tested for autism if a biological connection can be established with ASD.