Related Experiment Video
Updated: May 2, 2026
In Vivo Functional Study of Disease-associated Rare Human Variants Using Drosophila
Published on: August 20, 2019
Mutations in riboflavin transporter present with severe sensory loss and deafness in childhood
Myriam Srour1, Maria Lisa Putorti, Jeremy Schwartzentruber
1Laboratory of Neurogenetics of Motion, Montreal Neurological Institute, McGill University, Montréal, Canada; Division of Pediatric Neurology, Montreal Children's Hospital-McGill University Health Center, Montréal, Canada.
Introduction:
We have identified a large consanguineous Lebanese family with 5 individuals with severe childhood-onset recessive sensory loss associated with deafness and variable optic atrophy.
Methods:
Autozygosity mapping was performed in all affected individuals, followed by whole-exome sequencing (WES) in 2 individuals.
Results:
WES identified a homozygous missense mutation (c.916G>A, p.G306R) in the cerebral riboflavin transporter SLC52A2, recently shown to cause Brown-Vialetto-Van-Laere syndrome (BVVLS), which is considered primarily a motor neuronopathy. Our patients have a phenotype distinct from BVVLS, characterized by severe progressive sensory loss mainly affecting vibration and proprioception that evolves to include sensorineural hearing loss in childhood, variable degrees of optic atrophy, and marked upper extremity weakness and atrophy. Treatment of 3 patients with 400 mg/day riboflavin over 3 months produced definite clinical improvement.
Conclusions:
Mutations in SLC52A2 result in a recognizable phenotype distinct from BVVLS. Early recognition of this disorder is critical, given its potential treatability.
Related Concept Videos
01:20Inborn Errors of Metabolism
01:31Translation
Translation Produces the Building Blocks of Life
Proteins are...
01:31Translation
Translation is the process of synthesizing proteins from the genetic information carried by messenger RNA (mRNA). Following transcription, it constitutes the final step in the expression of genes. This process is carried out by ribosomes, complexes of protein and specialized RNA molecules. Ribosomes, transfer RNA (tRNA), and other proteins produce a chain of amino acids—the polypeptide—as the end product of translation.
Translation Produces the Building Blocks of...
01:20The Retinoblastoma Gene
The first-ever tumor suppressor gene called Rb was identified in retinoblastoma - a rare eye tumor in children. In inherited forms of the disease, a child inherits one defective copy of the Rb gene, which predisposes them to retinoblastoma. However,...
01:20The Retinoblastoma Gene
00:50Unrenewable Cells
Photoreceptors
The retina is composed of several layers and contains specialized cells called photoreceptors. The photoreceptors (rods and cones) change their membrane potential when stimulated by light energy. There are two types of photoreceptors—rods and cones—which differ in the shape of...