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Genotype-Phenotype Correlation for DFNA22: Characterization of Non-Syndromic, Autosomal Dominant, Progressive Sensorineural Hearing Loss due to MYO6 Mutations

Clinical and audiological examination was done in 2 Belgian families with autosomal dominant sensorineural hearing loss (SNHL) linked to DFNA22. Nineteen subjects in family 1 had mild to moderate SNHL starting in the third decade. The hearing loss was characterized by a flat audiogram affecting all tested frequencies with statistically significant progression. In family 2 eleven subjects were affected with mild to moderate SNHL starting in the second decade. Most of them showed a flat audiogram, but some had mid-frequency hearing loss. Significant progression of thresholds was present at 4 and 8 kHz. For all hitherto known DFNA22 families the audiological and clinical characteristics were correlated with the molecular data. This study describes the phenotype of 2 Belgian families with SNHL linked to DFNA22, both with a pathogenic change in the deafness gene MYO6. The phenotypes of all hitherto reported DFNA22 families with mutations in the MYO6 gene have been studied and compared. It seems that genetic defects that spare the motor domain of the myosin VI protein have a milder phenotype.

from Audiology & Neuro-Otology

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The large Chinese family with Y-linked hearing loss revisited: Clinical investigation

Conclusion. The DFNY1 phenotypes shared many characteristics with some autosomal dominant hearing loss, in the aspects of age of onset, severity and audiometric configuration. However, the typical, outstanding feature of this trait was its remarkable pattern of inheritance. Similar traits, if ever encountered, can be most easily identified by discerning this exceptional and rare pattern of inheritance. Objectives. To analyze the audiological features in Chinese Y-linked non-syndromic hearing impairment, the extended DFNY1 family. Subjects and Methods. A nine-generation Chinese family (DFNY1) was ascertained and expanded from the year of 2000 to 2006. The audiometric evaluations included pure-tone audiometry, tympanometry, and auditory brainstem responses. Some subjects received computerized tomography scan of the temporal bone. Results. 52 out of 276 members in this family received clinical examinations. 24 live subjects had hearing impairment consisting of 23 patrilineal males and one female. In the affected lineage, 92% patrilineal males were well characterized as having hearing loss and 2 children remained to be diagnosed. Based on the audiological examinations on the male members, the degree of hearing loss was from mild (3 patients), moderate (7 patients) to severe (11 patients). The audiometry displayed 48% subjects with sloping in high frequencies, 38% flat in all frequencies, and the rest (14%) the U-shape. The age of onset ranged from 5-27 years with the average of 11.5 years.

from Acta Oto-Laryngologica

The large Chinese family with Y-linked hearing loss revisited: Clinical investigation

from Acta Oto-Laryngologica

Abstract
Conclusion. The DFNY1 phenotypes shared many characteristics with some autosomal dominant hearing loss, in the aspects of age of onset, severity and audiometric configuration. However, the typical, outstanding feature of this trait was its remarkable pattern of inheritance. Similar traits, if ever encountered, can be most easily identified by discerning this exceptional and rare pattern of inheritance. Objectives. To analyze the audiological features in Chinese Y-linked non-syndromic hearing impairment, the extended DFNY1 family. Subjects and Methods. A nine-generation Chinese family (DFNY1) was ascertained and expanded from the year of 2000 to 2006. The audiometric evaluations included pure-tone audiometry, tympanometry, and auditory brainstem responses. Some subjects received computerized tomography scan of the temporal bone. Results. 52 out of 276 members in this family received clinical examinations. 24 live subjects had hearing impairment consisting of 23 patrilineal males and one female. In the affected lineage, 92% patrilineal males were well characterized as having hearing loss and 2 children remained to be diagnosed. Based on the audiological examinations on the male members, the degree of hearing loss was from mild (3 patients), moderate (7 patients) to severe (11 patients). The audiometry displayed 48% subjects with sloping in high frequencies, 38% flat in all frequencies, and the rest (14%) the U-shape. The age of onset ranged from 5-27 years with the average of 11.5 years.