Successful treatment of a genetic childhood ataxia due to riboflavin transporter deficiency.

Background: Riboflavin transporter deficiency (Brown-Vialetto-Van Laere syndrome) is a rare recessive neurodegenerative disorder that can present with gait ataxia, primarily due to sensory neuropathy as well as cerebellar involvement. Although sensorineural hearing loss, bulbar palsy, and optic atrophy are typical, presentation may be variable and an atypical condition may be difficult to recognize clinically.

Case Presentation: Here we report a patient presenting at age 8 with progressive ataxia since the age of 2.5 years with cerebellar atrophy and peripheral polyneuropathy. Whole exome sequencing identified a known pathogenic mutation in the gene consistent with a diagnosis of Brown-Vialetto-Van Laere syndrome despite the absence of common symptoms including motor neuropathy, bulbar palsy, optic atrophy, and sensorineural hearing loss. High-dose riboflavin therapy was initiated, symptoms stabilized, metabolic abnormalities resolved, and the patient is doing well with a near-normal examination at age 15.

Conclusions: Riboflavin transporter deficiency can be fatal if left untreated. The excellent outcome of this case illustrates the importance of identifying this potentially treatable neurologic condition. In this patient, clinical diagnosis was limited by an atypical presentation lacking several common features which was overcome through the use of genomic sequencing identifying the pathogenic mutation enabling correct diagnosis and subsequent treatment. Riboflavin transporter deficiency should be considered early in the diagnostic evaluation as a treatable form of ataxia in children, even if patients lack typical features.