Genetic link to nearsightedness discovered in Beduin tribe

LEPREL1 was identified by Ben-Gurion University professor as the cause of common human eye disorders.

By SHARON UDASIN
DNA strand double helix 311 (photo credit: Jerome Walker)
DNA strand double helix 311
(photo credit: Jerome Walker)
A Ben-Gurion University of the Negev professor and his research team have pinpointed a gene whose mutation leads in certain populations to myopia, nearsightedness, the most common human eye disorder and cause of many secondary eye disorders, the university announced Wednesday.
The gene, LEPREL1, was identified in studies conducted within a southern Israeli Beduin tribe led by Prof. Ohad Birk of the Morris Kahn Laboratory of Human Genetics at BGU’s National Institute for Biotechnology and the Dayan clinical genetics wing at Soroka University Medical Center, with principle research performed by Shikma Levin and Dr. Libe Gradstein, a statement from the university said.
While myopia is known to be a hereditary trait, leading to other disorders like retinal detachment, macular degeneration, cataracts and early onset glaucoma, no gene has yet been found as the specific link to its development, according to the statement.
“People from that tribe came into the ophthalmology department with severe myopia at an early age, Birk told The Jerusalem Post on Wednesday evening, noting that about one-third or one-fourth of the tribe’s members exhibit the disorder, and at “very severe” levels. “We figured that something unique was going on there.”
Birk’s team studied the defective gene among myopic members of the tribe and discovered that within LEPREL1, which encodes an enzyme necessary to modifying collagen after it is fully formed, a mutation can inhibit the presence of the active form of this enzyme, the university said. Due to the lack of the active enzyme, an abnormal modification of collagen arises, causing the eye to become longer than is typical and thereby allowing light to enter the eye’s focal point in front of the retina instead of on the retina itself, leading to nearsightedness.
“We are finally beginning to understand at a molecular level why nearsightedness occurs,” Birk said in the statement.
A manuscript of the group’s research appeared on Thursday in the American Journal of Human Genetics. Future studies will determine whether the mutation in LEPREL1 also leads to myopia in the general population, the university said.
“We will probably collaborate with people all over the world,” Birk told the Post, noting they would make use of gene banks of different populations everywhere.
While he cannot yet be certain, Birk said he expects to see myopia linked to this gene in some other populations, at least in mild cases of the disorder.
Meanwhile, although no type of medicine can currently repair the defect, he said that having a better understanding of the genetic link could potentially lead to remedies later on.
“I don’t know yet what we can do with this, but it’s interesting in the sense that it is the first gene-formed myopia,” Birk said.