The Hox9 mutants have no reported kidney defects, even when all four paralogs are mutated, likely a result of remaining Hox genes with overlapping function24, while Hox10 mutant kidneys show stromal defects when all three paralogs are mutated24, and Hox11 mutant kidneys have cap mesenchyme/UB branching defects that result in reduced nephron number, with renal agenesis when all paralogs are mutated16,17,19. This evidence concerns the gene VSX2 and renal agenesis.