Mammary-Digital-Nail Syndrome, also known as onycho-digito-mammary syndrome, is related to anonychia-onychodystrophy with brachydactyly type b and ectrodactyly and anonychia-onychodystrophy with hypoplasia or absence of distal phalanges. An important gene associated with Mammary-Digital-Nail Syndrome is MDNS (Mammary-Digital-Nail Syndrome). Affiliated tissues include breast and bone, and related phenotypes are nail dysplasia and nail dystrophy