The brachydactyly type C (BDC) phenotype includes brachymesophalangy of fingers 2, 3, and 5. The fourth finger is usually unaffected and thus appears as the longest finger of the hand. Shortening of metacarpal 1 and hyperphalangy in fingers 2 and 3 may occur and can be considered relatively characteristic signs. BDC can be highly variable, ranging from severely affected hands with very short fingers to mildly affected cases with only moderate brachydactyly, most often affecting the middle and proximal phalanges of fingers 2 and 3 (summary by Lehmann et al., 2006).

Any brachydactyly type A1 in which the cause of the disease is a mutation in the GDF5 gene.