New genetic link for rare colour blindness

A faulty ‘housekeeping’ gene has been found to be a cause of rare inherited condition, achromatopsia

eyes close-up

Researchers have uncovered a new link between a rare form of colour blindness and a faulty ‘housekeeping’ gene. The discovery may open up new avenues for gene-therapies to treat patients with the condition. 

The international group of researchers, which included geneticists from Moorfields Eye Hospital in London, studied 18 patients from 10 families with achromatopsia, a rare genetic condition affecting the cone cells of the retina.

Patients with the condition may be completely colour blind and have poor visual acuity. They also exhibit increased sensitivity to light and may have uncontrolled eye movements (nystagmus).

Achromatopsia affects an estimated one in 30,000 people worldwide, and while there is no effective treatment for the condition, light-filtering spectacles or red-tinted contact lenses may be prescribed to help alleviate the patient’s discomfort.

All 18 of the patients in the study were found to have faults in the same gene, ATF6, a ‘housekeeping’ gene expressed in cells throughout the body and involved in maintaining the activity of the cell’s protein production.

This new role of ATF6 in achromatopsia is unexpected and adds to the list of previously identified genes involved in the condition.

Professor Michel Michaelides, a consultant at Moorfields and one of the UK geneticists on the study, said: “Our findings show that, despite its ubiquitous role in the body, mutations in ATF6 can lead to isolated disease within the retina.”

He added: “This study advances our understanding of the underlying molecular genetic basis of achromatopsia and sheds light on macular developmental biology.”

Dr Dolores M Conroy, director of research for Fight for Sight, which partially funded the study, commented: “I’m really pleased to see this large international collaboration, including many research teams with different specialities, from Europe and North America, working together to make genetic discoveries. In this way we can help the people with very rare inherited eye conditions to receive specific diagnoses, and work towards developing targeted treatments.” 

The paper is published in Nature Genetics.