Most genetic professionals working with hearing loss are in general agreement that the cause of hearing loss in about one-quarter of cases is Unknown, one-quarter Non-genetic, and about one-half Genetic. For the purposes of this section, we will only focus on the genetic causes. Within the genetic half, about 70% of cases are generally thought to be recessive in nature, about 15% dominant and the remainder include all other inheritance types. The next section will explain these genetic terms in more detail.

Understanding genetics and inheritance
Many parents are unfamiliar with how hearing loss could be caused by genetic factors. As you work through the process of identifying the cause of your child's hearing loss, it will be helpful to have a basic understanding of genetics and the major categories of inheritance. If you are already familiar with genetic concepts, this list briefly summarizes the important points of genetic inheritance:

• Genes code for messages.
  
• Genes are found on chromosomes.
  
• Chromosomes come in pairs called homologs.
  
• The messages on each of the chromosomes in a pair may be different; those differences determine dominant or recessive expression of the gene message.
  
• The major forms of inheritance are Dominant, Recessive and Sex-linked.
  
• There are other types of inheritance.

For a more detailed tutorial, please click to the following section on basic genetics.