Supatra, Child With Ambras Syndrome, Thailand

Congenital forms of hypertrichosis are caused by genetic mutations. Congenital hypertrichosis forms are extremely rare, unlike acquired forms. Congenital hypertrichosis is always present at birth.
• Hypertrichosis lanuginosa
Congenital hypertrichosis lanuginosa is noticeable at birth with the infant completely covered in thin lanugo hair. In normal circumstances, lanugo hair is shed before birth and replaced by vellus hair; however, in a person with congenital hypertrichosis lanuginosa, the lanugo hair remains after birth. The palms of the hands, soles of the feet, and mucous membranes are not affected. As the person ages, the lanugo hair may thin leaving only limited areas of hypertrichosis.