To report 3 cases of pontobulbar palsy and sensorineural hearing loss (SNHL) with potentially different diagnoses.

Madras Motor Neuron Disease (MMND) and Brown-Vialetto-Van Laere (BVVL) syndrome are rare, progressive neurological disorders with considerable clinical overlap. An autosomal recessive mutation in an intestinal riboflavin transporter has been implicated in BVVL syndrome; however, the genetic basis and inheritance pattern of MMND are not clear. Treatment of both disorders is supportive, but high-dose riboflavin supplementation has demonstrated symptom improvement in BVVL syndrome.

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A 12 year old boy presented with an insidious onset of hearing loss since 1 year, followed by upper limb weakness, and difficulty speaking and swallowing. His father had suffered hearing loss and quadriparesis, and had died aged 30. On examination, bilateral upper limb muscle wasting and decreased deep tendon reflexes were noted. Whole Exome Sequencing revealed a likely pathogenic mutation in the SLC52A3 gene, consistent with BVVL syndrome. Swallowing improved following 2 months of riboflavin supplementation.

A 25 year old woman reported hearing loss, upper limb wasting, difficulty chewing, and slurring of speech that progressed over 15 years. Genetic analysis was not available, but symptoms remained static on riboflavin. A 20 year old woman presenting with decreased hearing, difficulty closing eyes, difficulty swallowing and upper limb wasting since 6 years was also started on riboflavin, and is due for genetic testing. She reported improvement in dysphagia on follow up.

All three cases showed severe SNHL on pure tone audiometry. Nerve conduction studies showed variable axonal neuropathy, electromyoneurography showed diffuse chronic denervation, and MRI brain and C spine were normal. However, the differential response to riboflavin prompted consideration of different diagnoses.

High dose riboflavin supplementation (up to 20 mg/kg/day) and genetic counselling should be initiated while awaiting results of genetic testing in patients presenting with pontobulbar palsy and SNHL.