Lelis syndrome is a rare condition that is characterized by a combination of ectodermal dysplasia and acanthosis nigricans. Ectodermal dysplasia in this condition commonly presents with features such as hypotrichosis, which means less than normal hair growth, and hypohidrosis, meaning a reduced ability to sweat. Acanthosis nigricans is often recognized by dark, thickened patches of skin, adding another layer to the clinical picture of this syndrome. People with Lelis syndrome experience these two sets of features together, which makes the condition notable among other rare disorders. Although the description is clear in linking the skin and hair abnormalities, the overall details about the variations in severity and the full range of symptoms remain less fully described in the current literature. This summary is based on the information available from established sources and may be updated as new scientific evidence emerges.

The main symptoms of Lelis syndrome include characteristics of ectodermal dysplasia, such as reduced hair growth (hypotrichosis) and decreased sweating (hypohidrosis), as well as the skin changes seen in acanthosis nigricans, which involves darkened and thickened skin patches. These signs help in recognizing the condition, though the full range of symptomatic variability is not completely detailed in the current sources.

Lelis syndrome is defined by the combination of features seen in ectodermal dysplasia and acanthosis nigricans. However, specific details about the causes or genetic factors underlying the condition are limited. At this time, information regarding the genetic causes or risk factors beyond the clinical description is not available.