Height SD scores (z-scores), proportion of children with severe short stature (z-score < −1.88), rates of growth hormone use, and annual change in height z-score were analyzed in children with ARPKD (n = 22) compared with two matched control groups: children with aplastic/hypoplastic/dysplastic kidneys (n = 44) and obstructive uropathy (OU) (n = 44). This evidence concerns the gene GH1 and urinary tract obstruction.