Novel Mutations in LRTOMT Associated With Moderate Progressive Hearing Loss in Autosomal Recessive Inheritance

Abstract

Objective: We present a patient who was identified with novel mutations in the LRTOMT gene and describe the clinical features of the phenotype including serial audiological findings. Methods: One hundred six Japanese patients with mild to moderate sensorineural hearing loss from unrelated and nonconsanguineous families were enrolled in the study. Targeted genomic enrichment and massively parallel sequencing of all known nonsyndromic hearing loss genes were performed to identify the genetic cause of hearing loss. Results: Compound heterozygotes with a novel frame-shift mutation and a missense mutation were identified in the LRTOMT gene. The mutated residues were segregated in both alleles of LRTOMT, present within the LRTOMT2 protein coding region. The patient had moderate sloping hearing loss at high frequencies, which progressed at 1000 Hz and higher frequencies over a period of 6 years. Conclusion: Hearing loss caused by mutations in the LRTOMT gene is extremely rare. This is the first case report of a compound heterozygous mutation in a nonconsanguineous family.