A genetic hearing loss is a hearing loss related to the genes. Gene mutations can cause hearing loss. Genetic factors make some people more susceptible to hearing loss than others. Genes contain the instructions that tell the cells of people’s bodies how to grow and work. There are many genes that are involved in hearing. Sometimes, a gene does not form in the expected manner. This is called a mutation. Some mutations run in families and others do not. If more than one person in a family has hearing loss, it is said to be “familial”. That is, it runs in the family. While many hereditary hearing losses are congenital (present at birth), some of these conditions develop slowly over time. The degree of loss can vary widely from person to person, even those with the same genetic condition.