Pattern Dystrophy of the Macula Associated with Maternally Inherited Diabetes and Deafness
Section outline
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A patient presented to Bascom Palmer Eye Institute for a second opinion regarding macular pigmentary changes, with roughly one year of visual distortion. The patient had a history of type 2 diabetes mellitus without documented retinopathy, ocular hypertension, and a laser-treated retinal tear. Family history was notable for mother with presumed macular degeneration and sister with diabetes. Dilated examination and multimodal imaging showed pigmentary macular changes consistent with pattern dystrophy of the retinal pigment epithelium. Previously obtained outside genetic testing was reviewed and confirmed a heteroplasmic, pathogenic MT-TL1 m.3243A>G mitochondrial DNA variant — the mutation responsible for maternally inherited diabetes and deafness (MIDD) and, at higher tissue heteroplasmy, mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). The patient was counseled regarding ultraviolet protection and was referred for evaluation of first-degree relatives and to medical genetics, with consideration of endocrinology, cardiology, and otolaryngology evaluation. This case illustrates how an ophthalmologist may be the first clinician to uncover a systemic mitochondrial disorder, and reviews the clinical features, multimodal imaging, differential diagnosis, and genetics of pattern dystrophy.
Presentation Date: 08/27/2026
Issue Date: 08/28/2026
