Male Subjects Affected By Hypohidrotic Ectodermal Dysplasia: Intrafamilial Variation

Inclusion Criteria: * Registered and attending the 2011 NFED Family Conference; * One year of age or greater; * Conform to one of the following requirements for providing informed consent/assent: * if more than 18 years of age, subjects must provide signed informed consent; * if less than 18 years of age and it is determined that the subject is capable of providing assent, both the assent of the subject and consent of the parent(s) or guardian of that subject must be granted. Under this condition, both parents of the subject should give their permission, unless 1 parent is deceased, unknown, incompetent, or not available; * if the subject is incapable of providing assent, the consent of the parent(s) or guardian of the subject must be granted. Under this condition, both parents should give their consent, unless 1 parent is deceased, unknown, incompetent, or not available. * As described in Section 3.2 above, subjects must meet one of the following criteria: * Male subjects with the clinical characteristics of HED, including at least a history of decreased sweating and either abnormal teeth (fewer permanent teeth, teeth are smaller than average and often have conical crowns), and/or sparseness of scalp and body hair (Male HED subjects with an affected sibling also enrolling in the study will be given priority to be in the study); * Healthy male controls, i.e. either unaffected male family members or unaffected male volunteers. Exclusion Criteria: * Known hyperse…