Retinopathy associated with Machado–Joseph disease (spinocerebellar ataxia 3) with CAG trinucleotide repeat expansion

Abstract

PURPOSE: To report characteristic atrophic maculopathy in a patient with Machado–Joseph disease (spinocerebellar ataxia 3) caused by trinucleotide repeat expansion of the relevant gene. METHODS: Case report. RESULTS: A 64-year-old Japanese man had suffered from slurred speech and gait disturbance since 57 years of age. Cerebellar ataxia, extensor plantar response, and other neurological signs were compatible with features of Machado–Joseph disease. Magnetic resonance imaging showed atrophies of cerebellum and cerebral cortex. Family history suggested an autosomal dominant inheritance of the disease. The patient presented with gaze-evoked nystagmus and limitations of eye movement in all directions. Ophthalmoscopy and fluorescein angiogram revealed symmetric changes in the posterior fundi, which consisted of patchy atrophies at the level of the retinal pigment epithelium. Scotopic electroretinogram showed no abnormalities with normal oscillatory potentials. Polymerase chain reaction analysis of the Machado–Joseph disease gene identified a heterozygous trinucleotide (CAG) repeat expansion. CONCLUSION: This case illustrates a rare association of atrophic maculopathy and external ophthalmoplegia in Machado–Joseph disease, contrasted with the common occurrence of retinal degeneration in spinocerebellar ataxia 7. Dystrophic changes in the retinal pigment epithelium have rarely been described but may be one of the characteristic complications of Machado–Joseph disease.