Yariz et al. (2012) studied 3 brothers and a sister, born of consanguineous parents, who had symmetric moderate sensorineural hearing loss with no evidence of progression on available audiograms. Clinical examinations did not reveal additional findings, and CT ... Yariz et al. (2012) studied 3 brothers and a sister, born of consanguineous parents, who had symmetric moderate sensorineural hearing loss with no evidence of progression on available audiograms. Clinical examinations did not reveal additional findings, and CT scan of the temporal bone in 1 affected sib was normal. In 1 brother who reported a 3-month episode of dizziness at age 17 years, described as a few seconds of blurry vision caused by turning his head abruptly to the left, caloric tests revealed left-sided vestibular hypofunction. All positional tests produced persistent up-left nontorsional nystagmus with an average velocity of 7 degrees/sec without a sensation of vertigo. Yariz et al. (2012) also studied 3 brothers from an unrelated family with congenital moderate stable hearing loss, who performed normally in the Unterberger, Romberg, head-thrust, and head-shake tests as well as in eye-tracking movements, although a delay in gross motor development was reported. There were no abnormalities on physical examination or otoscopy, and high-resolution CT scan in 1 of the affected brothers did not reveal any abnormalities.
In 4 sibs from a consanguineous family with nonsyndromic nonprogressive sensorineural hearing loss mapping to chromosome 12, Yariz et al. (2012) performed Sanger sequencing of the PTPRQ gene (603317) but identified no mutation. Whole-exome sequencing of 1 affected ... In 4 sibs from a consanguineous family with nonsyndromic nonprogressive sensorineural hearing loss mapping to chromosome 12, Yariz et al. (2012) performed Sanger sequencing of the PTPRQ gene (603317) but identified no mutation. Whole-exome sequencing of 1 affected sib revealed homozygosity for a 1-bp deletion in the OTOGL gene (614925.0001) predicted to cause premature termination. All 4 affected sibs were homozygous for the truncating OTOGL mutation as well as for a C1378R missense mutation in OTOGL which, being located toward the C terminus relative to the 1-bp deletion, was thought to be unlikely to contribute to the phenotype. In 3 brothers from an unrelated family with stable moderate hearing loss, Yariz et al. (2012) identified compound heterozygosity for a nonsense mutation (614925.0002) and a splice site mutation (614925.0003) in the OTOGL gene. The unaffected parents in each family were heterozygous for the mutations, respectively, which were not found in controls.