IRVINE : Tuberous Sclerosis Gene Marker Found

A team of scientists including a UC Irvine geneticist has discovered a genetic marker for an inherited disorder that can produce tumors in the brain or other organs.

Finding the genetic marker for the disease known as tuberous sclerosis is a key step in the search for the actual gene that causes the disorder, said Dr. Moyra Smith, a professor of pediatric genetics at UCI.

The discovery, reported in the journal Nature Genetics, means it is now possible to search for the genetic marker for tuberous sclerosis in prenatal tests such as amniocentesis. Smith said, however, that such tests would be done only when there is a family history of the disease.

“What is maybe even more important is that the marker could be used in pre-symptomatic diagnosis, where a person had a family history of the disease but no symptoms themselves,” said Smith, one of a team of physicians led by Raymond Kandt of the Bowman Gray School of Medicine in Winston-Salem, N.C.

Tuberous sclerosis is a disease characterized by tuber-like growths in the brain, kidney, skin or other tissue. It is found in about one in 10,000 people, and it crosses all cultural and ethnic lines.

Tuberous sclerosis can produce a range of symptoms from mild to severe. It is most often diagnosed because of its effects on the brain. The brain tumors can produce seizures and possibly even mental retardation. In kidneys, the tumors can lead to renal failure.

In the journal article, researchers detail finding the marker in a study of five large families in which 47 of 85 members have tuberous sclerosis. The marker, called D16S283, is a small piece of genetic material on human chromosome No. 16.

The next step for researchers is to explore human chromosomes No. 16 and No. 9 to look for the gene that causes tuberous sclerosis. Based on earlier research, Smith said, chromosome No. 9 is also believed to be a site for that gene.

Thanks to the federally funded Human Genome Project, a national effort to map the genes of the human body, considerable research has already been done on those chromosomes.

“The fact that we’re going into quite well-mapped territory, not into a desert, I think will help us find the gene in just a few more years,” said Smith.