title: Massively parallel DNA sequencing facilitates diagnosis of patients with Usher syndrome type 1.
abstract: Usher syndrome is an autosomal recessive disorder manifesting hearing loss, retinitis pigmentosa and vestibular dysfunction, and having three clinical subtypes. Usher syndrome type 1 is the most severe subtype due to its profound hearing loss, lack of vestibular responses, and retinitis pigmentosa that appears in prepuberty. Six of the corresponding genes have been identified, making early diagnosis through DNA testing possible, with many immediate and several long-term advantages for patients and their families. However, the conventional genetic techniques, such as direct sequence analysis, are both time-consuming and expensive. Targeted exon sequencing of selected genes using the massively parallel DNA sequencing technology will potentially enable us to systematically tackle previously intractable monogenic disorders and improve molecular diagnosis. Using this technique combined with direct sequence analysis, we screened 17 unrelated Usher syndrome type 1 patients and detected probable pathogenic variants in the 16 of them (94.1%) who carried at least one mutation. Seven patients had the MYO7A mutation (41.2%), which is the most common type in Japanese. Most of the mutations were detected by only the massively parallel DNA sequencing. We report here four patients, who had probable pathogenic mutations in two different Usher syndrome type 1 genes, and one case of MYO7A/PCDH15 digenic inheritance. This is the first report of Usher syndrome mutation analysis using massively parallel DNA sequencing and the frequency of Usher syndrome type 1 genes in Japanese. Mutation screening using this technique has the power to quickly identify mutations of many causative genes while maintaining cost-benefit performance. In addition, the simultaneous mutation analysis of large numbers of genes is useful for detecting mutations in different genes that are possibly disease modifiers or of digenic inheritance.
authors.affiliation: Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
authors.forename: Hidekane
authors.initials: H
authors.lastname: Yoshimura
authors.affiliation: Department of Hearing Implant Sciences, Shinshu University School of Medicine, Matsumoto, Nagano, Japan; Department of Otorhinolaryngology, International University of Health and Welfare, Mita Hospital, Minatoku, Tokyo, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Iwasaki
authors.affiliation: Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
authors.forename: Shin-Ya
authors.initials: SY
authors.lastname: Nishio
authors.affiliation: Department of Otolaryngology, Okinaka Memorial Institute for Medical Research, Toranomon Hospital, Minatoku, Tokyo, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Kumakawa
authors.affiliation: Department of Otorhinolaryngology-Head and Neck Surgery, Miyazaki University School of Medicine, Miyazaki, Miyazaki, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tono
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Iwate Medical University, Morioka, Iwate, Japan.
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Iwate Medical University, Morioka, Iwate, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Sato
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Nagai
authors.affiliation: Department of Otolaryngology, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Saitama, Japan.
authors.forename: Kotaro
authors.initials: K
authors.lastname: Ishikawa
authors.affiliation: Department of Otolaryngology, Saitama Medical University, Moroyama, Saitama, Japan.
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ikezono
authors.affiliation: Department of Otolaryngology, Kobe City Medical Center General Hospital, Kobe, Hyougo, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Naito
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Okayama University Postgraduate School of Medicine, Dentistry and Pharmaceutical Science, Okayama, Okayama, Japan.
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Fukushima
authors.affiliation: Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Fukuoka, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Oshikawa
authors.affiliation: Department of Otorhinolaryngology, Kyushu Central Hospital, Fukuoka, Fukuoka, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kimitsuki
authors.affiliation: Department of Otorhinolaryngology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nakanishi
authors.affiliation: Department of Otorhinolaryngology, Shinshu University School of Medicine, Matsumoto, Nagano, Japan.
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Usami
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000483:Alleles; D019943:Amino Acid Substitution; D002648:Child; D004252:DNA Mutational Analysis; D005091:Exons; D005260:Female; D056726:Genetic Association Studies; D005820:Genetic Testing; D005838:Genotype; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D010641:Phenotype; D052245:Usher Syndromes / Q000175:diagnosis* / Q000235:genetics*; D055815:Young Adult