All these findings imply that the majority of causes of CAKUT are still unknown, while the list of novel variants requiring functional characterization is extending [29], including variants in FRAS1, FREM2, GRIP1, ITGA8 and TRAP1 in which recessive mutations have been previously characterized [120,121] providing evidence that CAKUT might in some cases be an autosomal recessive disease. This evidence concerns the gene TRAP1 and congenital anomaly of kidney and urinary tract.