Anomalie osseuse rare: brachydactylie non syndromique de type C

Brachydactyly is a congenital shortening of the hands or toes related to the absence or small size of phalanges, metacarpal or metatarsal bones. It is a rare anomaly, easily detected in routine clinical practice, but for which a radiological assessment is indispensable. We here present the case of a 40-year old patient presenting with mechanical pain at the base of the right thumb associated with trapezio-metacarpal osteoarthritis also known as rhizarthrosis and in whom a shortening of the 2nd, 3, 4 and 5 fingers of both hands was discovered fortuitously on examination (A). The feet were spared. There were no other dysmorphic disorders (ocular, nasal, auricular or digestive). The interview revealed the same disorder only in patient’s mother, without consanguinity. Standard frontal xray of both hands showed brachymesophalangy of second, third and fifth rays (B). This type of brachydactyly is more complex. The fourth ray is spared, thus appearing as the longest finger. Brachydactyly can be classified into five different types from A to E. Standard radiography is the key examination for the characterization of the brachydactylies, specifying their topography and type of involvement. Several forms of brachydactyly are caused by mutations in the genes encoding bone morphogenetic proteins components. Brachydactylies can also be integrate into a large number of polymalformative syndrome. Our patient suffers from a isolated non-syndromic brachydactyly type C with autosomal dominant inheritance pattern.