Timothy syndrome: A childhood disorder characterized by severe cardiac arrhythmia, syndactyly (webbing) of the fingers and toes, congenital heart disease, intermittent hypoglycemia (low blood sugar), cognitive abnormalities and autism. The syndrome is due to spontaneous mutation in the gene for the CaV1.2 calcium channel, a pore-like protein that nestles in the cell membrane and controls the flow of calcium into and out of the cell. The syndrome is named for Katherine W. Timothy at the University of Utah who first described it in 1989.
