The overall purpose of this study is to learn more about Hypohidrotic Ectodermal Dysplasia (HED) and to help in identifying treatment opportunities. Several evaluations will be conducted in this study: 1) the number of skin sweat glands you have and their ability to produce sweat; 2) your ability to grow hair; 3) the structure of your face compared to faces of people affected by HED; 4) molds of your teeth to see if and how they are different than people affected by HED.

Inclusion Criteria:

1. Males age 14-29 years with clinical diagnosis of HED
2. No scalp shaving in the 6 months prior to enrollment
3. No current medical therapy for hair loss
4. Written informed consent for study and genotyping (or signed medical release of previous genetic test results)

Exclusion Criteria:

1. Medically significant condition as determined by the PI
2. Known hypersensitivity to pilocarpine or pilocarpine-like muscarinic agonists (e.g. Urecholine, Salagen, Pilocar, Provocholine)
3. Presence of cardiac pacemaker

HED Affected Members of the UCSF Craniofacial Clinic, HED Affected Members of the National Foundation for Ectodermal Dysplasia