Genes that cause MacTel – a rare disease of the retina – remain elusive, but a new study from an international team of researchers has narrowed the search. The researchers combed through the genomes of more than 450 patients and identified five small regions of the genome where MacTel genes are likely to reside.

The findings should help researchers uncover how MacTel develops and design therapies to prevent loss of vision, says Rando Allikmets, PhD, the William and Donna Acquavella Professor of Ophthalmic Sciences, who led the team’s genetics group.

The results were published in the journal Nature Genetics.

MacTel (short for macular telangiectasia type 2) is often misdiagnosed as the more common age–related macular degeneration because both involve overgrowth of blood vessels behind the retina.

The new findings suggest that MacTel may instead get its start in the retina’s Müller cells that keep the retina’s neurons healthy. The study found that some potential MacTel genes appear to alter normal enzymatic activity in the eye, which may impair Müller cells. Targeting the enzymes, the researchers speculate, could keep Müller cells–and thus retinal cells–healthy.

More research is needed to confirm the involvement of the genes identified in the study and how they cause MacTel. Dr. Allikmets says more genes are probably involved in MacTel, and he is currently working on studies with more MacTel patients to find these missing genes.