BMP4 and congenital anomaly of kidney and urinary tract: Given the requirement of the SHH-FOXF1-BMP4 regulatory axis for SMC differentiation in the ureter and the severity of the hydroureter formation associated with their complete or partial loss in the mouse, it is obvious that the components of this axis represent candidate genes for human congenital anomalies of the kidney and urinary tract (CAKUT).