Bipolar disorder is a common psychiatric disease that affects up to 2 percent of the population and is responsible, according to researcher Dr. Edward Ginns, for more disability than cancer.
Ginns and other researchers at the University of Massachusetts Medical School (UMMS) and the University of Miami Miller School of Medicine (UMMSM) recently discovered what they believe to be a key genetic pathway that may be an underlying cause of bipolar disorder.
Edward I. Ginns, MD, PhD is a neurologist and geneticist and was lead author of the study. He believes the research points to new avenues of study that could lead to new and better treatments for bipolar disease.
The study incorporated research collected over a 40-year time span on a select group of Old Order Amish families in Pennsylvania.
One of these families had an unusually high incidence of bipolar disease, as well as a high incidence of a rare genetic disorder called Ellis–van Creveld (EVC) syndrome, which causes dwarfism.
Ginns explained that while only 1-2 percent of the overall population of the United States have bipolar disorder, within this family as many as 15-20 percent of all members have bipolar.
The researchers noted that although all family members were at high risk for bipolar disorder, none of the family members who had EVC dwarfism also had bipolar disorder.
This was notable because the Amish family is part of an ethnically closed population. Environmental factors were common to all members of the family, regardless of which disease they had.
The researchers looked for a common factor that appeared to protect some members of the family from the disease. They determined that the protection was the genetic disorder that caused EVC dwarfism.
EVC dwarfism is caused by genetic mutations that interfere with the genetic pathway known as sonic hedgehog (Shh).
“Since mutations causing EvC do so by disrupting Shh protein function, linking abnormal Shh signaling to major affective disorders provides a concrete molecular and medical basis for patients’ symptoms that should help break down the stigma associated with mental illnesses,” said Ginns.