Gene tied to childhood brain disorder.

A child between the ages of 5 and 10 years suddenly goes blind. Seizures occur with increasing frequency, and the child inexorably loses his or her mental faculties. Death generally strikes by age 20.

This tragic sequence typifies Batten disease. Afflicting an estimated 1 in 25,000 newborns, it's the most common neurodegenerative disorder striking children. The only way physicians have been able to distinguish Batten disease from other disorders is by noticing the accumulation of certain pigments and proteins within neurons and many other cell types--an accretion that may cause the illness or be simply a by-product of the true problem.

"A lot of times the diagnosis is difficult or even missed," says Terry J. Lerner of Massachusetts General Hospital in Boston.

The International Batten Disease Consortium, to which Lerner belongs, has finally tracked down the mutated gene responsible for the devastating brain disorder. In 1989, investigators placed the blame somewhere on chromosome 16. Now, Lerner and her colleagues have found a gene on that chromosome that is mutated in all the Batten patients they've studied so far. Most of them have an identical chunk of the gene deleted, the consortium reports in the Sept. 22 Cell.

Identification of the gene should help physicians diagnose the disease quickly. A treatment for the condition may emerge if investigators can determine how the protein encoded by the gene works in healthy individuals.

"We would like to find out what it is doing in the normal cell," says Lerner, who notes that investigators will examine whether the gene's protein accumulates abnormally in Batten patients.