<s>[INST] <<SYS>> This is a medical question of type : frequency <</SYS>> How many people are affected by hypohidrotic ectodermal dysplasia ? [/INST] Hypohidrotic ectodermal dysplasia is the most common form of ectodermal dysplasia in humans. It is estimated to affect at least 1 in 17,000 people worldwide. </s>