Polydactyly, Postaxial, Type A2, also known as postaxial polydactyly, type a2, is related to polydactyly and simpson-golabi-behmel syndrome, type 1. An important gene associated with Polydactyly, Postaxial, Type A2 is PAPA2 (Postaxial Polydactyly, Type A2). Related phenotype is postaxial hand polydactyly.