Phenotypic Variability Related to Mutations in Riboflavin Transporter in Brazilian Children: Pediatric Case Series

Abstract

Brown–Vialetto–Van Laere syndrome or riboflavin transporter deficiency is a rare and genetically determined condition that results in a spectrum of neurological signs and symptoms from generalized muscle weakness to cranial nerve involvement with medullary symptoms and respiratory failure. Most patients have SLC52A3 gene biallelic variants, but some of them may have impairment of SLC52A2 gene, both related to the cell transport of riboflavin. We report the case of three unrelated Brazilian patients under 18 years of age with this diagnosis confirmed by molecular genetic sequencing. We observed that the clinical manifestations found were compatible with those already described in the literature by age group. Unusual findings of retinitis pigmentosa and immunodeficiency were identified related to pathogenic variants in the SLC52A2 gene. All patients received riboflavin replacement at a therapeutic dose without gastrointestinal intolerance and with clinical improvement after starting treatment.