Polydactyly, Preaxial I, also known as ppd1, is related to acropectoral syndrome and polydactyly, preaxial ii. An important gene associated with Polydactyly, Preaxial I is GLI1 (GLI Family Zinc Finger 1). Affiliated tissues include bone and bone marrow, and related phenotypes are preaxial hand polydactyly and partial duplication of thumb phalanx