Fazio-Londe syndrome (FL) and Brown-Vialetto-Van-Laere syndrome (BVVL), two very rare forms of bulbospinal muscular atrophy, have been considered until now as vitamin B2 transporter deficiencies, or riboflavinopathies. Iranian clinicians report an observation that tends to challenge this assumption:
- the patient, aged 25, had all the characteristics of a FL syndrome, with damage to pairs of cranial nerves (without deafness) associated with muscular weakness of motoneural origin,
- her parents were consanguineous and her three older brothers were healthy,
- she did not respond to high-dose riboflavin supplementation per os,
- the two genes known to be responsible for FL and BVVL were excluded by genetics,
- a broader exome study revealed a possibly pathogenic variant in theTNRC18 gene.
The involvement of this gene is still speculative at this stage, as no other cases have been reported to date.
