title: Atypical, perhaps under-recognized? An unusual phenotype of Friedreich ataxia.
abstract: Friedreich ataxia (FRDA) is typically characterized by slowly progressive ataxia, depressed tendon reflexes, dysarthria, pyramidal signs, and loss of position and vibration sense with onset before 25 years. While several atypical forms of FRDA are recognized, profound vision deficit is rare. We describe here a 41-year-old man with profound vision deficit and episodic complete blindness associated with marked optic atrophy, spastic paraparesis, and sensory neuropathy without ataxia whose diagnostic evaluation revealed compound heterozygosity for two frataxin mutations, a 994 GAA repeat intronic expansion and c.389G > T (p.G130V) missense mutation. This case emphasizes that FRDA should be considered for individuals with significant vision deficit with optic atrophy and sensory neuropathy, even in the absence of ataxia. This case also raises the additional, related concern that prior studies may underestimate the frequency and varieties of variant forms of FRDA.
authors.affiliation: National Hospital for Neurology and Neurosurgery, London, UK.
authors.forename: Beate
authors.initials: B
authors.lastname: Diehl
authors.forename: Michael S
authors.initials: MS
authors.lastname: Lee
authors.forename: Janet R
authors.initials: JR
authors.lastname: Reid
authors.forename: Craig D
authors.initials: CD
authors.lastname: Nielsen
authors.forename: Marvin R
authors.initials: MR
authors.lastname: Natowicz
mesh_terms: D000328:Adult; D001766:Blindness / Q000209:etiology* / Q000235:genetics / Q000473:pathology; D001921:Brain / Q000473:pathology; D005621:Friedreich Ataxia / Q000150:complications / Q000235:genetics / Q000503:physiopathology; D006801:Humans; D033862:Iron-Binding Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D009900:Optic Nerve / Q000473:pathology; D010641:Phenotype; D000096923:Frataxin
chemical_list: D033862:Iron-Binding Proteins; D000096923:Frataxin