The Genetics of Auditory Disorders

Several factors can cause auditory disorders. The foundational trigger is genetics. Over 50 percent of newborns that present hearing issues have genetic issues that are the source of the problem. Hearing loss is an inheritance trait known as a genotype.

Genes are the instructions cells follow as they grow and develop. Mutations can develop in genes and passed on from generation to generation, which is known as a familial trait. Mutations can also develop anew. For example, exposure to radiation can cause them.

  • When both parents have a genetic predisposition for hearing loss it is passed onto a child and, if it manifests itself, is known as autosomal recessive hearing loss. This occurs even though both parents have normal hearing — the condition was just dormant in the parents.
  • With autosomal dominant hearing loss, a predisposition from one parent or a new mutation of a gene leads to hearing loss.
  • Males are far more common to be affected by X-linked hearing loss, in which a gene mutation in the X chromosome — of which males have one and females two — manifests itself.
  • Syndromes of the mitochondria, which are vital parts of cells that produce energy, can be passed on genetically and create issues in the functioning of the ear.

The fact is that the inner ear is a very complex example of evolved design. The cochlea, which converts sound waves into electrical signals and sends them through the nervous system to the brain, is a mechanism that requires a vast number of genetic instructions to develop properly.

Only a handful of genetic “wrong turns” can lead to hearing issues. That only about 1 percent of babies are born with genetic hearing loss is actually a profound testament to the majesty of biology.