Using new imaging techniques, researchers at the National Eye Institute have determined that retinal lesions from vitelliform macular dystrophy (VMD) are differentiated by gene mutations. Addressing these differences may be key to designing effective treatments for these and other rare diseases. NI is part of the National Institutes of Health.
“NIA’s long-term investment in imaging technology is changing our understanding of eye diseases,” said NEI Director Michael F. Chiang, MD. It can inform the development of treatment.”
VMD is an inherited disease that causes progressive vision loss due to damage to the light-sensing retina. Genes implicated in VMD include BEST1, PRPH2, IMPG1, and IMPG2. Depending on the gene and mutation, the onset and severity are very different. All forms of the disease have a common lesion in the central retina (macula) that consists of egg yolk-like and toxic fatty substances called lipofuscin. VMD affects about 1 in 5,500 Americans and there is currently no treatment for this condition.
Johnny Tam, PhD, chief of NIH’s Division of Clinical and Translational Imaging, used multimodal imaging to evaluate the retinas of VMD patients at the NIH Clinical Center. TAM multimodal imaging uses adaptive optics — a technique that uses deformable mirrors to improve resolution — to visualize living cells in the retina, including light-sensing photoreceptors, retinal pigment epithelial (RPE) cells, and blood vessels in unprecedented detail.
Tam and his team collaborated with clinicians at the NIH Eye Clinic to identify 11 participants through genetic testing and other clinical evaluations, and evaluated their retinas using multimodal imaging. Evaluation of cell densities (photoreceptors and RPE cells) near VMD lesions revealed differences in cell densities according to different mutations. IMPG1 and IMPG2 mutations had a greater effect on photoreceptor cell density than RPE cell density. The reverse was true for PRPH2 and BEST1 mutations. In participants with only one affected eye, the researchers reported a similar effect on cell density in the unaffected eye, despite no damage.
TAM is also using multimodal imaging in a variety of other rare retinal diseases and common diseases, including age-related macular degeneration.
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Materials provided by NIH/National Eye Institute. Note: Content may be edited for style and length.
