Riboflavin transporter deficiency (RTD) is a progressive inherited neuropathy of childhood onset, characterised by pontobulbar
palsy, sensorineural
deafness,
sensory ataxia,
muscle weakness,
optic atrophy and
respiratory failure.
Riboflavin supplementation is beneficial in short-term reports, but the quantum of benefit in various clinical domains is not well understood. A PubMed search was conducted, which identified 94 genetically confirmed cases of RTD who received
riboflavin supplementation and had follow-up assessments. Information on the clinical and functional status before and after
riboflavin supplementation was collected and analysed. Seventy-six of the 94 patients (80.9%) showed an overall improvement after
riboflavin supplementation, and the remaining (19.1%) were stable, though some patients had deteriorations in individual domains with no reported deaths. The domains that had the highest rates of response to
riboflavin supplementation were gross motor function (93.3% improved),
bulbar palsy (91.3%) and
ataxia (90.0%). Improvements were also seen in limb
muscle weakness, audiology, facial nerve
palsy and respiratory function. Despite treatment, many patients required assistance to ambulate and had severe or profound
hearing loss and some remained
gastrostomy or
tracheostomy dependent.
Riboflavin supplementation is a lifesaving intervention for patients with RTD and results in a profound improvement in several functional domains, with early diagnosis and treatment further improving outcomes. Despite treatment, patients are left with residual disability. There is a need to accurately measure functional outcomes in children with RTD and develop additional disease-modifying
therapies.