Sorsby Macular Dystrophy

We present the case of a 33-year-old male who presented with visual distortions in the left eye. Visual acuity was 20/20 in the right eye and 20/30 in the left eye. Fundus examination revealed reticular pseudodrusen in both eyes, and a choroidal neovascular membrane in the left eye for which he was treated for 2 weeks prior with intravitreal bevacizumab at an outside institute. Given his young age, fundus examination and a positive family history of Sorsby Macular Dystrophy (+father), genetic testing was done and revealed a positive TIMP3 mutation. Swept source optical coherence tomography angiography (SS-OCTA) was performed and revealed thickened bruch’s membrane, decreased choriocapillaris thickness and decreased choriocapillaris flow. This is the in vivo demonstration with these features in Sorsby Macular Dystrophy. At 8-month follow up, the patient continued to remain stable without the need for additional intravitreal injection treatments. Sorsby Macular Dystrophy is an autosomal dominant retinal dystrophy due to a mutation in the tissue inhibitor of metalloproteinase-3 (TIMP3) gene. The prevalence is 1 in 220,000 individuals. The disease presents in the third to fourth decade. The disease involves deposition of lipid and protein in bruch’s membrane, that leads to its thickening and eventual atrophy and/or choroidal neovascular membrane formation. Treatment involves treating the choroidal neovascular membrane with intravitreal anti-VEGF agents. This patient’s family pedigree was studied, and 5 additional members were identified and studied using SS-OCTA. Of these five additional members, 3 members were tested positive for the TIMP3 mutation.

Presentation Date: 06/17/2021

Issue Date: 07/02/2021