The research shows that children who have the syndrome develop spontaneous genetic mutations that interfere with calcium channels that regulate the excitation and contraction of the heart. In defining the precise nature of the molecular abnormality, however, the researchers have also identified a class of drugs that they hope will alleviate the arrhythmia.
Timothy syndrome may also cause a form of autism in those affected, and there is the possibility that understanding more about the nature of these calcium channel defects could improve understanding of autism, which affects 200,000 to 400,000 children in the United States. Calcium channels are pore-like proteins that nestle in cell membranes and control the flow of calcium into and out of the cell. Calcium is one of the most important signaling molecules in the body, and perturbing calcium transport can cause a wide range of disorders.
Howard Hughes Medical Institute investigator Mark T. Keating and his colleagues reported in the October 1, 2004, issue of the journal Cell, that a pinpoint mutation in the CaV1.2 calcium channel was the sole cause of Timothy syndrome. Keating collaborated on the studies with researchers from Children's Hospital, Boston, Harvard Medical School, the University of Utah, the University of Pavia in Italy and the Boston University School of Medicine.
The scientific path that led to the identification of the cause of Timothy syndrome began in 1989 with the identification of a single child with the then nameless disorder by Katherine W. Timothy of the University of Utah. That child presented with cardiac arrhythmia and a webbing, or syndactyly, of the hands and feet characteristics of what has now come to be called Timothy syndrome in honor of Kather
Contact: Jim Keeley
Howard Hughes Medical Institute