In situ hybridization analysis of Wnt4, Wnt5a and Wnt7a, the Wnt genes involved in MD development, indicated that the MD and its surrounding stromal cells in both the wild-type and the Wnt4mCh/mCh embryos were positive for the Wnt4 RNA probe at E14.5 (Fig. 4C and D). Here, WNT7A is linked to Menkes disease.