Prevalence of macular pattern dystrophy in maternally inherited diabetes and deafness

Objective: To evaluate the prevalence of macular pattern dystrophy (MPD) in maternally inherited diabetes and deafness (MIDD), a new subtype of diabet es mellitus that cosegregates with a mutation of mitochondrial DNA (i.e., t he substitution of guanine for adenine at position 3243 of leucine transfer RNA) and to report the clinical characteristics of MPD. Design: Prospective cohort study. Participants: Forty-six patients from 29 families with an adenine-to-guanin e mutation of mitochondrial DNA were recruited from a French collaborative multicenter study. Thirty-five patients had MIDD, 8 were asymptomatic child ren of MIDD patients, and 3 had MELAS syndrome (mitochondrial myopathy, enc ephalopathy, lactic acidosis, and strokelike episodes). The 33 MIDD patient s with diabetes were matched for diabetes duration and gender with 33 patie nts with "common" type-2 diabetes to compare the prevalence of diabetic ret inopathy (DR) in both series. Methods: All patients had a full ophthalmologic examination and fundus phot ographs. Main Outcome Measures: The presence and severity of MPD and DR were assesse d in each patient. Results: Thirty MIDD patients (85.7%) of 35 exhibited bilateral MPD charact erized by linear pigmentation surrounding the macula and optic disc. In 24 of these 30 patients, visual acuity was 20/25 or more in both eyes. The pre valence of DR was 6% in MIDD patients with diabetes versus 15% for patients with common type-2 diabetes (a difference that was not significant, P = 0. 23). The fundus of each of the eight asymptomatic children was normal. MPD was present in one of the three cases of MELAS. Conclusion: The prevalence of MPD in MIDD is high. Its detection may be hel pful for the diagnosis of this new subtype of diabetes, for which specific treatments may be proposed.