Early-Onset Hearing Loss in Leber's Hereditary Optic Neuropathy: A Case Report

Leber hereditary optic neuropathy (LHON) is one of the most common mitochondrial disorders that is characterized in young adults and teenagers as bilateral, painless, subacute visual failure. Extraocular manifestations include neurological and cardiac features. Sensorineural hearing loss (SNHL) has not been reported as a clinical feature of this disorder. We report a patient diagnosed with LHON having the common m.11778G>A; p. Arg340 pathogenic variant who was also diagnosed with bilateral mild-to-moderate high-frequency SNHL as a neonate through our provincial newborn screening program. Genetic workup, including a next-generation sequencing "Comprehensive Hereditary Hearing Loss Panel" for common and non-syndromic hearing loss and sequencing of the mitochondrial genome, was negative for a second pathogenic variant. The infectious workup was negative. Non-enhanced magnetic resonance imaging of the brain and internal auditory canal was normal. To our knowledge, SNHL has not been reported before as a clinical feature of patients diagnosed with LHON, and hence this rare and unusual presentation merits reporting.