Nail Disorder, Nonsyndromic Congenital, 4, also known as anonychia congenita, is related to epidermolysis bullosa and anhidrosis. An important gene associated with Nail Disorder, Nonsyndromic Congenital, 4 is RSPO4 (R-Spondin 4), and among its related pathways/superpathways are Keratinization and Hair follicle development: organogenesis - part 2 of 3. Affiliated tissues include bone and skin, and related phenotypes are anonychia and growth abnormality