Brachydactyly type C (BDC) is a very rare congenital malformation characterized by brachymesophalangy of the index, middle and little fingers, with hyperphalangy of the index and middle finger and shortening of the 1st metacarpal. Only few families with BDC have been reported in the literature. The ring finger is usually the longest digit. Short metacarpals and symphalangism are occasionally present. Heterozygous mutations in the cartilage-derived morphogenetic protein 1, also known as growth/differentiation factor-5 gene (<i>GDF5</i>), have been reported in BDC patients. Many studies support an autosomal dominant mode of inheritance.

A phalangeal malformation that is termed angel-shaped phalanx (ASP), because of its resemblance to the angels used for decoration of Christmas trees. The various components of an angel-shaped phalanx are: diaphyseal cuff (wings), surrounding a meta-diaphyseal core (body), which may appear empty or structured with a cone-shaped epiphysis (skirt) and pseudoepiphysis (head).