sentences:  CMD is caused by chromosomal abnormalities, generally spontaneously arising or "de novo" mutations, in or around the gene SOX9 on the long arm of chromosome 17, specifically at position 17q24.The SOX9 gene codes for a protein transcription factor which, when expressed at the embryonic stage, plays an important role in determining sexual characteristics and greatly influences skeletal development.When the SRY gene of the Y chromosome is expressed in human embryos, a cascade of gene interactions controlled by SOX9 begins and ultimately leads to male gender.