Congenital Adrenal Hyperplasia (CAH) is one of the commonest inherited diseases, affecting 1:14,200 live births. It is the result of a genetic defect in one of the enzymes (in most cases 21-hydroxylase) required for cortisol biosynthesis, leading to reduced levels of cortisol and aldosterone, increased ACTH concentrations and consequently increased adrenal androgen production. Patients suffer from problems with growth and development and as adults patients may have problems with fertility, virilisation in women, testicular masses in men and both men and women have an impaired quality of life. Patients have to take life-long therapy. Despite its frequency knowledge surrounding the management of adults with CAH remains fairly limited. There has been a lot of work describing the management of children with CAH but to date there is no consensus on how to manage adults. To address this issue a number of adult endocrinologists in the UK under the auspices of the Society for Endocrinology have established a country wide study (CaHASE) to undertake research in order to set standards of care for adult patients with CAH.

In CAH the severity of the symptoms experienced by affected individuals varies depending on the mutation and the genetic background of the individual. The ability to tailor CAH therapy on an individual basis, as determined by the severity of the underlying defect and an understanding of the likely natural history of the disease, is a key goal in clinical management. Correlation of phenotype (clinical status) and genotype (the underlying 21 hydroxylase gene mutation) will facilitate stratification of severity and provide an important contribution to the debate on potential mechanisms of individualised therapy. For instance it may become clear that certain CAH genotypes are associated with specific long term outcomes. In time, this could lead to suggesting different treatment strategies in certain groups. Moreover, genotype data are important if we are to address the relative contribution of environment (e.g. treatment) vs. genetics on long term outcomes.

This multi-centre study aims to:

1. - Investigate the medical health of adults with congenital adrenal hyperplasia.
2. - Investigate the relationship between the genotype of the patient and the phenotype.
3. - Investigate the quality of life of adults with congenital adrenal hyperplasia.