Genetic testing in clinical endocrinology.

Mendelian disease (due to disruption of a single gene) will be dealt with first as it accounts for a considerable proportion of endocrine disorders, represents the simplest and best understood instance of the contribution of genetics to endocrinology, and has given rise to routine diagnostics already available to clinicians. Complex disorders, depending on the interaction of environmental factors with a multitude of genetic loci, however, account for the bulk of the morbidity and mortality the endocrinologist has to deal with (obesity, diabetes, hyperlipidemias, autoimmune thyroid disease, most endocrine tumors, most disorders of growth and puberty). The molecular contribution to these disorders is less deterministic and complex and is only now beginning to be elucidated with the use of novel concepts and technologies. Before getting into specifics, a general overview of the human genome and its relationship to function will be given.