title: An Usher syndrome type 1 patient diagnosed before the appearance of visual symptoms by MYO7A mutation analysis.
abstract: Usher syndrome type 1 (USH1) appears to have only profound non-syndromic hearing loss in childhood and retinitis pigmentosa develops in later years. This study examined the frequency of USH1 before the appearance of visual symptoms in Japanese deaf children by MYO7A mutation analysis. We report the case of 6-year-old male with profound hearing loss, who did not have visual symptoms. The frequency of MYO7A mutations in profound hearing loss children is also discussed. We sequenced all exons of the MYO7A gene in 80 Japanese children with severe to profound non-syndromic HL not due to mutations of the GJB2 gene (ages 0-14 years). A total of nine DNA variants were found and six of them were presumed to be non-pathogenic variants. In addition, three variants of them were found in two patients (2.5%) with deafness and were classified as possible pathogenic variants. Among them, at least one nonsense mutation and one missense mutation from the patient were confirmed to be responsible for deafness. After MYO7A mutation analysis, the patient was diagnosed with RP, and therefore, also diagnosed with USH1. This is the first case report to show the advantage of MYO7A mutation analysis to diagnose USH1 before the appearance of visual symptoms. We believed that MYO7A mutation analysis is valid for the early diagnosis of USH1.
authors.affiliation: Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Japan.
authors.forename: Hidekane
authors.initials: H
authors.lastname: Yoshimura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iwasaki
authors.forename: Yukihiko
authors.initials: Y
authors.lastname: Kanda
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakanishi
authors.forename: Toshinori
authors.initials: T
authors.lastname: Murata
authors.forename: Yoh-ichiro
authors.initials: Y
authors.lastname: Iwasa
authors.forename: Shin-ya
authors.initials: SY
authors.lastname: Nishio
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Takumi
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Usami
mesh_terms: D044466:Asian People; D002648:Child; D002675:Child, Preschool; D000072259:Connexin 26; D017630:Connexins; D004252:DNA Mutational Analysis; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009154:Mutation; D000081412:Myosin VIIa; D009218:Myosins / Q000235:genetics*; D052245:Usher Syndromes / Q000175:diagnosis* / Q000235:genetics*
chemical_list: D017630:Connexins; C000607042:GJB2 protein, human; C000631455:MYO7A protein, human; D000081412:Myosin VIIa; D000072259:Connexin 26; D009218:Myosins