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• Posted December 23, 2025

Faulty Genes Don't Always Lead To Vision Loss, Blindness

Genetics aren’t necessarily destiny for those with mutations thought to always cause inherited blindness, a new study says.

Fewer than 30% of people with these genetic variants wind up blind, even though the faulty genes had been thought to cause blindness in 100% of those with them, according to findings published Dec. 22 in the American Journal of Human Genetics.

The results could shake up a central belief in genetics, that faulty genes always lead to rare inherited disorders. These disorders are called Mendelian diseases, named after the famed genetics researcher Gregor Mendel.

“These findings are striking and suggest that the traditional paradigm of Mendelian diseases needs to be updated,” senior researcher Dr. Eric Pierce, director of the Ocular Genomics Institute at Mass Eye and Ear in Boston, said in a news release.

The study focused on inherited retinal degenerations (IRDs), a group of genetic diseases that lead to progressive vision loss and eventual blindness. They cause the light-sensing cells along the back wall of the eye to break down and die off.

For the study, researchers created a list of 167 variants in 33 genes that have been previously linked to IRDs.

The team then screened nearly 318,000 people participating in a National Institutes of Health research program for the presence of those variants, and found 481 with IRD-causing genetics.

However, only 28% of those people had suffered any form of retinal disease or vision loss, and just 9% had a formal IRD diagnosis, results showed.

The team double-checked their work by using data on about 100,000 participants in another large-scale study, the UK Biobank.

Again, only 16% to 28% of people with IRD-linked genetics had suffered definite or possible signs of vision loss or retinal damage, researchers said.

The results suggest that something else is happening alongside a person’s genetic risk to make them wind up with IRD, including environmental factors or other faulty genes, researchers said.

“We think these findings are important for understanding IRDs and other inherited diseases,” researcher Dr. Elizabeth Rossin, an investigator at Mass Eye and Ear, said in a news release.

“We look forward to finding modifiers of disease and using that new knowledge to improve care for patients with IRDs and potentially other inherited eye disorders,” Rossin said.

Future studies will examine other Mendelian disorders, and look for other genetic and environmental factors that could cause these diseases.

“The large number of individuals that do not develop an IRD despite having a compatible genotype provide an opportunity to design well-powered research studies to discover disease modifiers, which could spur development of novel therapies,” lead researcher Dr. Kirill Zaslavsky said in a news release. Zaslavsky performed this research during an Inherited Retinal Disorders fellowship at Mass Eye and Ear.

More information

Prevent Blindness has more on inherited retinal diseases.

SOURCE: Mass General Brigham, news release, Dec. 22, 2025

What This Means For You

People with genetics linked to vision loss and blindness might be able to ward off these problems, if researchers figure out what’s behind the diseases.