Two homologues, Dach1 and Dach2, are known in mice and humans21, 22 as well as the 4 homologues dacha, dachb, dachc and dachd in zebrafish.23, 24Dach1−/− mice survive to birth, but die shortly thereafter by unknown reasons with no abnormalities in eye, limb and brain development.25 Also it was observed that in mgb−/− mice, a model system of congenital obstructive nephropathy and hydronephrosis, Dach1 was one of the top up‐stream inhibited regulators.26 This evidence concerns the gene DACH1 and hydronephrosis.