PLXNA2 and Chondrodysplasia - disorder of sex development: Of these, four genes were determined to be related to bone development (PLXNA2 with prognathism, HHAT with the complex Nivelon-Nivelon-Mabille Syndrome, MBOAT2 with chondrocyte differentiation, and ITGAV with chondrodystrophy), and one to calcium homeostasis (HPCAL1).