Friedreich’s ataxia and more: Optical coherence tomography findings in rare neurological syndromes

Optic nerve and retinal involvement are a frequent finding in many neurodegenerative disorders. Optic atrophy can be severe and diffuse or sectorial and can be associated with visual complaints and reduction of visual acuity. We here report the main optical coherence tomography (OCT) findings in rare neurological syndromes for which OCT data are available. In Friedreich’s ataxia, which is an autosomal recessive disease, there is evidence of subclinical optic neuropathy. OCT studies describe a diffuse reduction of the retinal nerve fiber layer (RNFL) thickness without a specific and preferential involvement of the papillo-macular bundle. Jansky-Bielschowsky disease is a late infantile neuronal ceroid lipofuscinosis characterized by both retinal and optic nerve atrophy. Only one OCT study is available describing retinal abnormalities of various degrees. DNA (cytosine-5)-methyltransferase 1 (DNMT1) disease is an autosomal dominant multisystem disorder characterized by the association of narcolepsy, deafness, sensory neuropathy and optic atrophy. The only OCT study available from our group describes the presence of subclinical optic atrophy more evident in the temporal quadrant. Hereditary spastic paraplegia due to SPG7 mutation is an autosomal recessive neurodegenerative disorder characterized by spastic paraparesis. RNFL thinning is a frequent and consistent finding in this disease. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an autosomal dominant disorder in which retinal vascular changes and neurodegeneration of the neuroretina are frequent findings. Wolfram’s disease is a disorder characterized by the occurrence of diabetes mellitus and optic atrophy. The only two OCT studies available report a diffuse optic atrophy which leads to a severe reduction of visual acuity. Autosomal recessive spastic ataxia of Charlevoix-Saguenay (ARSACS) is a hereditary spastic ataxia due to progressive degeneration of the cerebellum and spinal cord, characterized by retinal nerve fiber hypertrophy detected by OCT. Spinocerebellar ataxias (SCAs) are heterogeneous genetically determined disorders for which OCT studies available show variable findings ranging from isolated thinning of the temporal RNFL to retinal photoreceptor abnormalities.