Deafness can be an inherited condition that is present when a baby is born. Inherited deafness can also develop over time during childhood or adulthood. According to the American Hearing Research Foundation, about 1 out of every 1,000 to 2,000 births involves congenital deafness. A recessive autosomal genetic condition is responsible for more than 75% of congenital deafness cases. There are many different genetic mutations that can cause deafness that is present at birth, and parents do not always realize right away that their babies have hearing loss or are deaf. Some cases of genetic deafness are a part of a disorder that causes other disabilities, but about 70 to 80% of congenital deafness is a stand-alone disorder.
According to the Centers for Disease Control, about 20 to 30% of people who are born with deafness inherited from their parents also have other disabilities. One of the most common disabilities that occurs with deafness is vision abnormalities. Babies born with deafness may also have other developmental delays that can be a part of their genetic inheritance or due to significant prematurity.
When a child is born with a genetic disorder that causes deafness, it is important for the child to undergo thorough evaluations with ear, nose and throat doctors and audiologists. These specialists can identify co-morbid conditions such as speech and swallowing disorders that might cause the child to have further problems with growth and development. An early diagnosis helps a baby to get early intervention. Early intervention services might include speech therapy, hearing aids, surgery for cochlear implants, and other services to help the child reach their full potential.
Autosomal recessive deafness also affects boys and girls equally. A parent who might or might not be deaf has a 25% chance of passing the mutation to a child. There are several different genetic mechanisms that can cause deafness. Sex-linked deafness results from a mutation on the X chromosome. This type of deafness is most often expressed in boys. Girls are rarely affected because it takes two copies of the mutated gene to cause deafness in girls, who carry two X chromosomes. The American Academy of Otolaryngology explains that autosomal dominant hearing loss is rare and affects boys and girls in equal numbers. A parent with the gene has a 50% chance of passing it on to their child.