The development of normal skin, hair, teeth and nails is physically, socially and psychologically important. Unfortunately, this state of affairs is not the case for a few thousand people in the UK who are born with genetic abnormalities that affect tissue development. These conditions are known as ‘ectodermal dysplasias’. Very little is known about what causes ectodermal dysplasia and there are no specific treatments, so the aim of this project is to discover the gene abnormalities which lead to the poor development of these tissues. This information will then provide the basis for better genetic counselling for affected families, and allow for a more precise diagnosis and foundation on which to plan newer forms of therapy.