Scientists discover gene tied to profound vision loss

An exhaustive hereditary analysis of a large Louisiana family with vision issues has uncovered a new gene tied to the incurable eye disorder retinitis pigmentosa, according to a study led by scientists at The University of Texas Health Science Center at Houston (UTHealth). This family of eye diseases affects more than 200,000 people in the United States and millions worldwide.

In the journal Investigative Ophthalmology & Visual Science, Stephen P. Daiger, PhD, and his colleagues report their discovery of a new gene tied to retinitis pigmentosa. The gene, hexokinase 1 (HK1), brings the total of genes associated with the disorder to more than 60.

“This information is important because it helps affected families cope with the disorder, helps explain its biologic basis, and suggests targets for drug treatments and gene therapy,” says Daiger. “The challenge now is to block the activity of these mutations, and clinical trials are underway to do just that.”

For approximately three decades, Daiger, a member of the Human Genetics Center at the UTHealth School of Public Health, has been following the progress of hundreds of families across the country with retinitis pigmentosa. “We've found the cause of disease in 80 percent of the families we have studied,” Daiger says. “Our goal is to find the cause in the remaining 20 percent.”

Equipped with the genetic profiles of family members, Daiger's team has identified differences in the genetic makeup of those with the disease. The researchers also use family histories and DNA tests to glean information about the condition's hereditary nature.

“The story of the HK1 mutation is itself interesting. What we found is a mutation present in families from Louisiana, Canada, and Sicily. Our evidence suggests the mutation arose in a common ancestor who lived centuries ago,” Daiger says. “The mutation spread in Europe and North America, and may be common among Acadians in Louisiana. This is called a founder mutation.”