ABSTRACT

This chapter is for readers who feel threatened by genetics, who are apt to see genetics as a malignant growth, taking over familiar areas of medicine and rendering them strange and incomprehensible. It is a survival kit but also an entry ticket to this most intellectually exciting area of biomedical science. Genetics is not taking over medicine; it is burrowing under it and rearranging the foundations. Genetics is relevant to hearing and deafness at two levels. In everyday clinical practice, effective diagnosis and management of patients require some familiarity with common patterns of inheritance and with the availability, use, and limitations of genetic tests. More fundamentally, to understand the causes and pathology of hearing impairments, we need to understand the molecular pathology of the genes that program cells in the inner ear. What follows is a review of the concepts and vocabulary of genetics as it applies to both these levels. Italicised words are defined in the Glossary at the end of this chapter. For readers who would like more detail, references are given below to the relevant sections of Strachan & Read Human Molecular Genetics; the text of the second edition (“S&R2”) is freely available on the NCBI Bookshelf website (1).