Two novel mutations of MYO7A complicated with peripheral retinal dysplasia in a patient with Usher syndrome: a case report

Usher syndrome (USH) is an inherited disorder characterized by hearing loss, progressive retinal degeneration and variable vestibular dysfunction. It is categorized into three major clinical subtypes, and Type I (USH1) is the most severe which characterized by severe to profound congenital sensorineural deafness, vestibular hypofunction, and prepubertal onset retinitis pigmentosa. Six genes have been reported to be associated with USH1 and MYO7A mutation is found in 29–60% of cases. We report an 11-year-old child presented with hearing loss, peripheral retinal dysplasia and noninfectious uveitis. Next generation sequencing revealed two novel heterozygous variants of MYO7A , c.1990A > C and c.1630_1632del, confirming the molecular diagnosis of USH. We report a previously undescribed phenotype caused by two novel mutations in MYO7A , which expands the mutation spectrum and contributes to explore the underlying pathogenesis of USH. Further studies are needed to confirm this finding.