[5] Osr1, which encodes a zinc-finger DNA-binding protein, and LIM-type homeobox gene (Lhx1) expression overlaps the intermediate mesoderm as well as the lateral plate.

The cells of the pronephric duct migrate caudally whilst inducing adjacent mesenchyme to form the tubules of the initial kidney-like structure called the pronephros.

[5] The mesonephros functions between the 6th and 10th weeks of embryological life of mammals as a temporary kidney, but serves as the permanent excretory organ of aquatic vertebrates.

[9] The permanent kidney of amniotes, the metanephros, develops during the 10th week in human embryos and is formed by the reciprocal interactions of the metanephrogenic blastema (or metaneophrogenic mesenchyme) and the ureteric bud.

[1] Once the bud invades the metanephrogenic blastema, a permissive signal in the form of Wnt proteins is activated and stimulates the condensation of metanephric mesenchymal cells around the ureteric bud tips, beginning the polarisation of the blastema to generate the epithelial cells of parts of the nephron: the proximal tubules, loops of Henle and the distal convoluted tubules.

[2] Condensing mesenchyme then secretes paracrine factors that mediate branching of the ureteric bud to give rise to the ureter and collecting duct of the adult kidney.

[12] WTs are often a result of a genetic deletions or inactivating mutations in WT1 (Wilms tumor 1), which subsequently inhibits Wnt/βcatenin signalling and prevents MET progression.

[14] In a smaller percentage of cases, the cause of PMDS is not fully understood but is related to complex malformations of the urogenital region and paramesonephric ducts during male gonadal development.