A research team at the University of Utah found that low levels of a protein known as HTRA1 could be a trigger for the development of age-related macular degeneration (AMD) in specific individuals.
HTRA1 is critical in maintaining the area of the eye at the interface between the retinal pigmented epithelium (RPE) and the Bruch's membrane as people age and typically the levels of this protein increase with age.
Researchers found that genetic variants on chromosome 10 prevent the HTRA1 gene from behaving properly in certain people, which in turn leads to the development of AMD. The HTRA1 protein levels can drop by up to 50% in people with this genetic variant.
By analyzing mRNA levels in eye tissue samples donated by organ donors, researchers found that mRNA encoding HTRA1 was low in RPE tissue but not in neural retina or choroid tissues. Researchers were able to determine that the decrease of the levels was due to a regulatory element that impacts gene expression, which seems to become less functional in patients who are carriers of the AMD-related gene variants.
Developing a possible therapy for this specific type of AMD is now the goal of the research team. While there is no treatment for the dry form of AMD, taking AREDS supplements may help slow the progression of the disease.