Hereditary hypotrichosis simplex of the scalp

Hereditary hypotrichosis simplex of the scalp is a genotrichosis characterized by sparse or absent scalp hair without structural defects, in the absence of other ectodermal or systemic abnormalities. We describe two Spanish families with hypotrichosis of the scalp. We believe these families have Toribio and Quiñones type hereditary hypotrichosis simplex of the scalp.