Two cases ofcampomelic dysplasia CD and sexual reversion XY in a couple of univitelin twins, are presented. This is the second paper published in the medical literature. The differences in patients phenotype let to discuss the existen ce of variability in DC expressivity. The association of XY sexual reversion and campomelic dysplasia of Short bones permit us to refute affirmations published in that way. Finally we state and discuss the autosomic recesive gen ligament of the CD with gen or genes of the sexual differentiation.
