title: Clinical characteristics of a Japanese family with hearing loss accompanied by compound heterozygous mutations in LOXHD1.
abstract: OBJECTIVE
  To report two novel LOXHD1 mutations, including missense mutations and the clinical features of the patients.
  
  
  METHODS
  We studied a three-generation Japanese family with hearing loss. Targeted next-generation sequencing was used for genetic analysis. Conditional orientation response audiometry and pure tone audiometry were used to assess hearing. SWISS-MODEL was used for molecular modeling of the PLAT domain in LOXHD1 protein.
  
  
  RESULTS
  The two sisters, who had either mild or severe high-frequency hearing loss, were compound heterozygous for two novel mutations (c.5674G>T [p.V1892F] and c.4212+1G>A) in LOXHD1, which is responsible for autosomal-recessive nonsyndromic hearing loss DFNB77. These cases showed less severe hearing impairment than the previously reported cases carrying LOXHD1 mutations, but their hearing loss appeared to be progressive. Molecular modeling predicted that distorted structure of the PLAT domain in the p.V1892F mutant could lead to decreased affinity of the protein to lipid membrane resulting in hair cell dysfunction.
  
  
  CONCLUSIONS
  We report a Japanese family carrying compound heterozygotes of truncating and nontruncating mutations in LOXHD1 identified by targeted NGS analysis. The fact of lower degree of hearing impairment in our cases than previously reported and the molecular modeling of the missense mutant provide insight to the genotype-phenotype correlation of DFNB77.
authors.affiliation: National Hospital Organization Tokyo Medical Center, Department of Otolaryngology, 2-5-1 Higashigaoka, Meguroku, Tokyo 152-8901, Japan; National Hospital Organization Tokyo Medical Center, National Institute of Sensory Organs, 2-5-1 Higashigaoka, Meguroku, Tokyo 152-8901, Japan.
authors.forename: Shujiro B
authors.initials: SB
authors.lastname: Minami
authors.affiliation: National Hospital Organization Tokyo Medical Center, National Institute of Sensory Organs, 2-5-1 Higashigaoka, Meguroku, Tokyo 152-8901, Japan.
authors.forename: Hideki
authors.initials: H
authors.lastname: Mutai
authors.affiliation: National Hospital Organization Tokyo Medical Center, National Institute of Sensory Organs, 2-5-1 Higashigaoka, Meguroku, Tokyo 152-8901, Japan.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Namba
authors.affiliation: Hyogo Prefectural Kobe Children's Hospital, Department of Otolaryngology, 1-1-1 Takakuradai, Sumaku, Koube, Hyogo 654-0091, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Sakamoto
authors.affiliation: National Hospital Organization Tokyo Medical Center, Department of Otolaryngology, 2-5-1 Higashigaoka, Meguroku, Tokyo 152-8901, Japan; National Hospital Organization Tokyo Medical Center, National Institute of Sensory Organs, 2-5-1 Higashigaoka, Meguroku, Tokyo 152-8901, Japan. Electronic address: matsunagatatsuo@kankakuki.go.jp.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Matsunaga
mesh_terms: D044466:Asian People / Q000235:genetics; D001299:Audiometry; D001301:Audiometry, Pure-Tone; D002352:Carrier Proteins / Q000235:genetics*; D002648:Child; D004252:DNA Mutational Analysis; D005260:Female; D005838:Genotype; D006316:Hearing Loss, High-Frequency / Q000235:genetics*; D006319:Hearing Loss, Sensorineural / Q000235:genetics*; D006579:Heterozygote; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D007223:Infant; D007564:Japan; D020125:Mutation, Missense; D010375:Pedigree; D010641:Phenotype; D035781:Siblings
chemical_list: D002352:Carrier Proteins; C543906:LOXHD1 protein, human
keywords: Autosomal-recessive nonsyndromic hearing loss; DFNB77; LOXHD1; Molecular modeling; PLAT domain; Targeted next-generation sequencing