Thursday, June 9, 2022
Genetic and clinical studies have identified a new type of macular degeneration that causes central vision impairment.
Researchers at the National Institute of Ophthalmology (NEI) have identified a new disease that affects the cornea, a small part of the light-sensitive retina needed for clear, central vision. The researchers report their findings on an unnamed new macular dystrophy in the journal JAMA Ophthalmology. NEI is part of the National Institutes of Health.
Macular dystrophies are diseases that usually result in central vision loss as a result of mutations in several genes. ABCA4, BEST1, PRPH2, the and TIMP3.
For example, patients with Sorsby Fundus Dystrophy have a specific genetic eye disease TIMP3 The types usually occur in adulthood. They often undergo sudden changes in visual acuity due to choroidal neovascularization – new, abnormal blood vessels that grow under the retina, affecting fluid flow and vision.
TIMP3 is a protein that helps regulate blood flow in the retina and is secreted by the retinal pigment epithelium (RPE), which is the supporting tissue layer that nourishes the light-sensitive photoreceptors in the retina. everything TIMP3 Gene mutations occur in a mature protein after being “cut” from RPE cells.
“It was amazing that we had two patients TIMP3 The options use a gene in a short signal sequence, not a mature protein, to “cut” the protein from the cells. We have shown these options to prevent division, which leads to the protein getting stuck in the cell, which is likely to lead to toxicity of the retinal pigment epithelium, ”said Bin Guan, Ph.D., lead author.
The study team followed these results with clinical evaluation and genetic testing of family members, two new TIMP3 The variants are associated with this atypical maculopathy.
“Affected individuals had scotomas, or blind spots, and changes in their macules that were a sign of disease, but so far they have retained central vision and no choroidal neovascularization, unlike typical Sorsby Fundus dystrophy,” said Katie Kukras, MD, Ph.D. .., Lasker’s researcher and retinal medicine specialist who clinically evaluated patients.
NEI’s Ophthalmic Genomics Laboratory collects and manages samples and diagnostic data from patients involved in several studies under the NEI Clinical Program to facilitate the study of rare eye diseases, including Sorsby Fundus Dystrophy.
“Discovering new mechanisms of disease, even in known genes TIMP3We hope it can help patients seeking the right diagnosis and lead to new therapies for them, ”said Rob Hufnagel, MD, Ph.D., senior author and director of the Ophthalmic Genomics Laboratory at NEI.
The study was funded by the NEI Intramural Research Program.
NEI leads the federal government’s study on vision and eye diseases. NEI supports basic and clinical science programs to develop treatments to save the eye and address the special needs of visually impaired people. For more information, visit https://www.nei.nih.gov.
About the National Institutes of Health (NIH):The NIH, the country’s medical research agency, includes 27 institutes and centers and is part of the U.S. Department of Health and Human Services. The NIH is a major federal agency that conducts and supports basic, clinical, and translational medical research and studies the causes, treatments, and cures for common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.
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Bin Guan, PhD, Laryssa A. Huryn, MD, Andrew B. Hughes, BS, Zhiyu Li, MD, Chelsea Bender, BS, Delphine Blain, MS, MBA, Amy Turriff, MS, Cathy A. Cukras, MD, PhD, Robert B. Hufnagel, MD, PhD. Early-onset TIMP3-associated retinopathy associated with signal peptide impairment. doi: 10.1001 / jamaophthalmol.2022.1822