Morell et al. (2000) reported a 3-generation family living in the U.S. Midwest in which some members had a bilateral, sloping, progressive, sensorineural hearing loss, first evident at 6,000 and 8,000 Hz. It was identified in some family ... Morell et al. (2000) reported a 3-generation family living in the U.S. Midwest in which some members had a bilateral, sloping, progressive, sensorineural hearing loss, first evident at 6,000 and 8,000 Hz. It was identified in some family members in the early teens but was clearly evident by the early twenties. The degree of hearing loss increased with age, and threshold shifts were seen at all frequencies. DeWan et al. (2003) described another U.S. family in which affected members had sloping audiograms with mid- and high-frequency hearing loss, which progressed to hearing loss that affected all frequencies. Mean age at onset of hearing impairment was 13.2 years, with a standard deviation of 4.6 years. Rendtorff et al. (2006) provided follow-up of a large Norwegian family originally reported by Teig (1968) with autosomal dominant sensorineural hearing loss spanning 7 generations. Age at onset was in the first or second decade of life. Hearing loss first affected high frequencies and progressed to involve all frequencies. Audiograms showed a sloping configuration with age, resulting in profound hearing loss. The rate of progression was variable, but most affected members in this family needed a hearing aid by age 20 years.
In affected members of 4 families with autosomal dominant progressive sensorineural hearing loss (DFNA20/DFNA26), Zhu et al. (2003) identified heterozygous mutations in highly conserved regions of the ACTG1 gene (102560.0001-102560.0004). Three of the families had been reported by ... In affected members of 4 families with autosomal dominant progressive sensorineural hearing loss (DFNA20/DFNA26), Zhu et al. (2003) identified heterozygous mutations in highly conserved regions of the ACTG1 gene (102560.0001-102560.0004). Three of the families had been reported by Yang and Smith (2000) and DeWan et al. (2003). The findings established that DFNA20 and DFNA26 are identical. In affected members of a Dutch family with autosomal dominant deafness linked to the 17q25 region, Van Wijk et al. (2003) identified a mutation in the ACTG1 gene (102560.0005). In 19 affected individuals of a large Norwegian family reported by Teig (1968), Rendtorff et al. (2006) identified a heterozygous mutation in the ACTG1 gene (102560.0006). Morin et al. (2009) reported 2 Spanish families with autosomal deafness and identified heterozygous mutations (102560.0007 and 102560.0008, respectively) in the ACTG1 gene.