title: Association between SCO2 mutation and extreme myopia in Japanese patients.
abstract: OBJECTIVE
  To investigate the role of SCO2 in extreme myopia of Japanese patients.
  
  
  METHODS
  In total, 101 Japanese patients with extreme myopia (axial length of ≥30 mm) OU at the Kyoto University Hospital were included in this study. Exon 2 of SCO2 was sequenced by conventional Sanger sequencing. The detected variants were assessed using in silico prediction programs: SIFT, PolyPhen-2 and MutationTaster. To determine the frequency of the mutations in normal subjects, we referred to the 1000 Genomes Project data and the Human Genetic Variation Database (HGVD) in the Human Genetic Variation Browser.
  
  
  RESULTS
  The average age of the participants was 62.9 ± 12.7 years. There were 31 males (30.7 %) and 70 females. Axial lengths were 31.76 ± 1.17 mm OD and 31.40 ± 1.07 mm OS, and 176 eyes (87.6 %) out of 201 eyes had myopic maculopathy of grade 2 or more. Among the 101 extremely myopic patients, one mutation (c.290 C > T;p.Ala97Val) in SCO2 was detected. This mutation was not found in the 1000 Genomes Project data or HGVD data. Variant type of the mutation was nonsynonymous. Although the SIFT prediction score was 0.350, the PolyPhen-2 probability was 0.846, thus predicting its pathogenicity to be possibly damaging. MutationTaster PhyloP was 1.268, suggesting that the mutation is conserved.
  
  
  CONCLUSIONS
  We identified one novel possibility of an extreme myopia-causing mutation in SCO2. No other disease-causing mutation was found in 101 extremely myopic Japanese patients, suggesting that SCO2 plays a limited role in Japanese extreme myopia. Further investigation is required for better understanding of extreme myopia.
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, 54 Kawahara, Shogoin, Sakyo, Kyoto, 606-8507, Japan.
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Wakazono
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, 54 Kawahara, Shogoin, Sakyo, Kyoto, 606-8507, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Miyake
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, 54 Kawahara, Shogoin, Sakyo, Kyoto, 606-8507, Japan. yamashro@kuhp.kyoto-u.ac.jp.
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamashiro
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, 54 Kawahara, Shogoin, Sakyo, Kyoto, 606-8507, Japan.
authors.forename: Munemitsu
authors.initials: M
authors.lastname: Yoshikawa
authors.affiliation: Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, 54 Kawahara, Shogoin, Sakyo, Kyoto, 606-8507, Japan.
authors.forename: Nagahisa
authors.initials: N
authors.lastname: Yoshimura
mesh_terms: D000328:Adult; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D004247:DNA / Q000235:genetics*; D004252:DNA Mutational Analysis; D005091:Exons; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D024101:Mitochondrial Proteins / Q000235:genetics* / Q000378:metabolism; D018832:Molecular Chaperones; D009154:Mutation; D009216:Myopia / Q000453:epidemiology / Q000235:genetics* / Q000378:metabolism
chemical_list: D002352:Carrier Proteins; D024101:Mitochondrial Proteins; D018832:Molecular Chaperones; C400285:SCO2 protein, human; D004247:DNA
keywords: Extreme myopia; Genetics; Japanese; Rare variant; SCO2