Posted on by Dr. Francis Collins
We know that heredity, along with environment, plays an important role in many mental illnesses. For example, studies have revealed that if one identical twin has bipolar disorder, the chance of the other being affected is about 60%. There are similar observations for autism, schizophrenia, and major depression. But finding the genes that predispose to these conditions has proven very tricky.
Now, an NIH-funded team at Baylor College of Medicine has demonstrated for the first time that extra copies of a gene that codes for a protein called Shank3 can cause manic episodes similar to those seen in some types of bipolar disorder . The researchers initially tested their hypothesis in mice and then, building upon those findings, went on to find extra copies of the SHANK3 gene in two human patients—one with seizures and attention deficit hyperactivity disorder and another with seizures and bipolar disorder.