Ulnar-Mammary Syndrome (UMS) is a disorder which is inherited in an autosomal dominant fashion. Children diagnosed with the disorder may have one affected parent or carry a spontaneous (de novo) variation in their T-Box3 (TBX3) gene. Not all TBX3 variants will result in UMS

Ulnar-Mammary Syndrome can be expressed differently in family members – even if they have the same variant in their gene. The symptoms may include limb anomalies ranging from malformation or duplication of fingernails to a congenital absence of one of the bones of the arm (ulna), and/or underdevelopment of mammary and sweat glands.

We are grateful to the family who participated in our research study and allowed us to understand and publish a new TBX3 variant, and helped us expand the diagnostic variants possible for UMS.

Descriptions of the UMS disorder are adapted from OMIM and NORD.