Researchers Get Clue to Eye Disease Genetics

Researchers at Childrens Hospital of Los Angeles and the USC School of Medicine say they can now identify many people who have inherited a defective gene known to be responsible for retinoblastoma, a childhood cancer of the eye.

The report in the current issue of Science is the latest from scientists who have isolated the gene. The Childrens Hospital team said its study provided the first proof that the gene that was isolated is indeed the gene responsible for the cancer.

Dr. Yuen-Kai Fung said isolating the gene has enabled the researchers to identify certain children who inherited the damaged gene. And Dr. William F. Benedict said a test to establish whether a fetus is carrying the damaged gene may now be possible.

Over the years researchers have learned that retinoblastoma occurs in both a hereditary and a non-hereditary form. If both eyes are affected, the disease is hereditary; if only one eye is involved, it is non-hereditary in 85% of the cases, according to Benedict.

Because of the risks associated with passing the hereditary form of the disease to one’s offspring, it is important to be able to distinguish the 15% of patients with the tumor in one eye who carry the defective gene from the 85% who do not so that proper counseling can take place, Benedict said.

In addition, those with the hereditary form also are more likely to develop bone cancer, he said.