The disease, named Timothy syndrome after one of the paper's authors, is characterized by a variety of problems including heart arrhythmias, congenital heart abnormalities, webbed hands and feet, a weakened immune system, cognitive abnormalities, and, surprisingly, autism. The researchers have identified 17 children with the syndrome, seven of whom were living.
Despite the complexity and severity of Timothy syndrome, the researchers show that it arises from a single, spontaneous, very subtle gene mutation in the mother's egg or father's sperm substitution of a single base pair. The reason so many body systems are affected is that mutation impairs a very fundamental molecule a type of calcium channel that is found in many tissues and organs.
Calcium channels control how much calcium can get inside a cell. Calcium is one of the body's most important signaling molecules, and normally, cellular calcium levels are tightly regulated. Dr. Mark Keating, senior author of the study and a Howard Hughes Medical Institute investigator at Children's Hospital Boston, likens the calcium channel to a screen door.
"After you go through the screen door, it automatically closes," he says. This mutation dismantles the automatic closing mechanism, so the door just stays open."
As a result, cells are overwhelmed by an influx of calcium. Because calcium-channel blocking drugs can ameliorate calcium overload, these medications may be useful for treating arrhythmia and cognitive deficits in individuals with Timothy syndrome, Keating says.