CNP and NTproCNP levels vary by Tanner stage. Bar, median; error bars, 25th and 75th percentiles. For boys, penile Tanner stage was used, for girls, breast Tanner stage. Children of Tanner stage I were older than 6 years of age; Children of Tanner stage V were less than 20 years of age. Top left panel, CNP levels for boys, top right panel, CNP levels for girls. Bottom left panel, NTproCNP levels for boys, bottom right panel, NTproCNP levels for girls. For all four panels, levels differed as group by Kruskal-Wallis Test (p<0.005 for all). *, p<0.05 compared to boys of Tanner stage I, II, and V by Dunn’s Test post hoc pair-wise comparison. †, p<0.05 compared to girls of Tanner stage IV and V.