The artist and model Melanie Gaydos discusses ectodermal dysplasia, which affects the development of teeth, nails and cartilage, a disorder responsible for her distinctive looks.

In humans, EDA gene mutations can lead to Hypohidrotic ectodermal dysplasia, which causes people to develop abnormal teeth, nails and sweat glands.

In the absence of the external ectodermal ducts usual in winged insects, these two groups resemble therefore the primitive Aptera.