Nonsyndromic Deafness, Autosomal Dominant
What is nonsyndromic deafness, autosomal dominant?
Nonsyndromic deafness is hearing loss that is not associated with other signs and symptoms. In contrast, syndromic deafness involves hearing loss that occurs with abnormalities in other parts of the body.
Nonsyndromic deafness is often genetic and can be described by its pattern of inheritance. An autosomal dominant inheritance pattern means that one copy of the altered gene in each cell is sufficient to result in hearing loss. Autosomal dominant deafness is designated DFNA. Each type is also numbered in the order in which it was described. For example, DFNA2 and DFNA3 are particular forms of autosomal dominant deafness.
Nonsyndromic deafness, autosomal dominant is a subtype of nonsyndromic deafness.
Most forms of autosomal dominant deafness are progressive, which means they become more severe over time. This type of hearing loss is most likely to develop after a person learns to speak (postlingual). The hearing loss may affect one or both ears and is usually caused by changes in the inner ear. The inner ear consists of a snail-shaped structure called the cochlea that helps process sound, nerves that send information from the cochlea to the brain, and structures involved with balance. Hearing loss caused by changes in the inner ear is called sensorineural deafness.
How common is nonsyndromic deafness, autosomal dominant?
Between 20 percent and 25 percent of all nonsyndromic deafness is inherited in an autosomal dominant pattern.
What genes are related to nonsyndromic deafness, autosomal dominant?
Mutations in the ACTG1, COCH, COL11A2, DFNA5, EYA4, GJB2, GJB6, KCNQ4, MYO6, MYO7A, TECTA, TMC1, and WFS1 genes cause nonsyndromic deafness, autosomal dominant.
The GJB3 and MYO1A genes are associated with nonsyndromic deafness, autosomal dominant.
Genes related to autosomal dominant deafness have been identified in only a small number of families. Many of these genes affect the structure or function of components of the inner ear; however, the function of several genes (such as TMC1 and WFS1) is unknown. Different mutations in the same gene can cause different types of hearing loss, and some genes are associated with both nonsyndromic and syndromic deafness.
In some families, deafness is thought to be caused by genetic factors, but the gene has not been identified.
How do people inherit nonsyndromic deafness, autosomal dominant?
In people with autosomal dominant deafness, hearing loss results from one copy of an altered gene in each cell. Affected individuals most often inherit the altered gene from a parent who has hearing loss.