Brown–Vialetto–Van Laere syndrome

Brown-Vialetto-Van Laere syndrome (BVVL), is a rare, progressive, inherited neurodegenerative disorder that most often manifests in infancy or early childhood. Since 2010, mutations in the SLC52A1, SLC52A2, or SLC52A3 genes, which encode riboflavin transporters, have been identified as the cause of BVVL. BVVL is now known as riboflavin transporter deficiency (RTD, OMIM 614707).

RTD types 2 and 3 are characterized by a diverse phenotypic spectrum encompassing motor, sensory, and cranial nerve neuropathies, leading to sensorineural hearing loss, optic atrophy, sensory ataxia, muscle weakness, ponto-bulbar palsy, and respiratory insufficiency. Without treatment, individuals with RTD types 2 and 3 experience severe disability and a rapidly progressive disease course, often culminating in fatal respiratory failure, particularly in those with early infancy onset.

Oral riboflavin supplementation has emerged as a life-saving treatment, significantly improving outcomes across multiple functional domains and slowing disease progression. Since 2010, approximately one hundred genetically confirmed cases of RTD have been reported in the literature, all of which were treated with high-dose oral riboflavin supplementation.