Genetic control of sebum excretion and acne--a twin study.

Sebum excretion and acne grades were measured in 20 pairs each of identical and non-identical like-sex twins. The identical twins had virtually identical rates of sebum excretion (P greater than 0.05), but they had a significantly different degree of acne severity (P less than 0.01). The non-identical twins had significantly different sebum excretion rates (P less than 0.01) and acne grades (P less than 0.01). These findings suggest that sebum excretion is under genetic control and the development of clinical lesions is modified by environmental factors.