Experimental Factor Ontology entry EFO_0010250 (polydactyly, postaxial, A9) is a form of postaxial polydactyly, a condition characterized by the occurrence of supernumerary digits in the upper and/or lower extremities. In postaxial polydactyly type A, the extra digit is well-formed and articulates with the fifth or a sixth metacarpal/metatarsal. PAPA9 is an autosomal recessive condition characterized by one or more posterior or postaxial digits.