SCIENCE / MEDICINE : Improved Disease Marker

The discovery of a new genetic marker “very closely linked” to Huntington’s disease should improve the reliability of tests to predict the inherited, degenerative disorder, researchers said last week.

Although the Huntington’s gene, itself, has yet to be isolated, a study published in the British journal Nature reports the discovery of a marker that lies so close to the disease gene that the two are almost always inherited together.

“It is very closely linked to the disease gene. At this point, we haven’t found a person with Huntington’s who doesn’t have the marker,” said John Wasmuth, a geneticist at the UC Irvine, who headed the study.

The symptoms of Huntington’s affect fewer than eight people in 100,000, and usually do not occur until a person is about 40 or 50, researchers said. By that time, the patient has often had children and passed the Huntington’s gene on to his or her offspring.

Wasmuth said a blood test employing the new marker, called D4S95, is “far easier to use” than past tests to predict Huntington’s and has an accuracy rate of about 99%, compared with a 95% rate for the marker previously used.

The research team, made up of scientists from UC Irvine, the University of British Columbia and Indiana University’s Medical School, also wrote that the marker could be “a new starting point for attempts to clone the disease gene.”