A mutation in the tiny channels that control calcium levels in a cell appears to be responsible for Timothy syndrome - a rare disorder characterized by irregular heartbeats and autism, new research suggests.

The mutation results in continuous inward flow of calcium, suggesting that it may be possible to treat the syndrome with certain heart drugs that block calcium channels, lead author Dr. Igor Splawski, from Harvard Medical School in Boston, and colleagues note in the scientific journal Cell.

The team has been working with children with Timothy syndrome since 1989, Splawski told Reuters Health. Of 17 cases he has seen, 10 died at an average age of 2.5 years. With treatment for the irregular heartbeats though, some of the children have survived, and one is still alive at age 20.

Other features of the syndrome include fused fingers, immune system deficiency, abnormal teeth, and intermittently low blood sugar levels.

Among affected patients who have survived past infancy, the researchers also observed impairments in language skills, movement, and thinking ability. Autism and related disorders is also common among patients with the syndrome.

Genetic analysis performed on 13 of the children revealed a calcium channel mutation in every case. Given the syndrome’s link with autism, Splawski said it is possible that calcium problems may also be found in children with the usual type of autism.

However, Splawski said it’s unlikely that such children would have the same mutation seen with Timothy syndrome, since they do not have the other symptoms associated with the disorder.

“But it is possible that other mutations in the same gene or similar genes may be associated with” the usual type of autism, he added.

SOURCE: Cell, October 1, 2004.