Patterned macular dystrophy as the first sign of maternally‐inherited diabetes and deafness (MIDD)

Abstract

PurposeMaternally inherited diabetes and deafness (MIDD) is a mitochondrial disorder characterized by the mutation of the mitocondrial DNA (mtDNA) at the 3,243 position. The prevalence accounts for 0.5–2.8% of all cases of diabetes. In more than 80% of cases it is associated with a good prognosis bilateral pattern macular dystrophy. We show the importance of ocular examination to diagnose MIDD.MethodsWe present a case report of MIDD.ResultsA 42 year‐old man was referred for a nonspecific blurred vision in both eyes since two months ago. Diabetes mellitus type 1 and migraine had been diagnosed at the age of 20. The patient wore a hearing aid because he had bilateral sensorineural hearing loss. Best‐corrected visual acuity (BCVA) was 20/20 in both eyes. Fundus examination revealed bilateral hyperpigmented lesions surrounding the macula combined with depigmented areas of retinal pigment epithelium (RPE). Spectral‐domain optical coherence tomography (SD‐OCT) showed hyperreflective dome‐shaped lesions corresponding to a hyperpigmented areas that seemed to originate from the RPE. Fundus autofluorescence (FAF) was characterized by a diffuse speckled appearance of the macula with decreased FAF signal in areas of RPE atrophy and irregular increased FAF signal between the areas of RPE atrophy. Results from automated static perimetry and magnetic resonance imaging (MRI) of the brain was unremarkable. We suspected MIDD and genetic testing of mtDNA confirmed a point mutation at the locus 3,243 with 85% heteroplasmy.ConclusionsOphthalmologists need to be aware in patients presenting patterned dystrophies of the RPE in the context of diabetes or deafness. It is possible that there are other family members with undiagnosed disorders related to mitochondrial mutation who would benefit from ophthalmic evaluation, auditory testing and screening for diabetes mellitus.