COL2A1 and familial hyperaldosteronism: In the present studies, we found that the FH phenotype was observed in Axin1 cKO (Axin1flox/flox;Prrx1-Cre) mice, but not in Axin1 cKO mice targeting in other cell populations, such as Sox9-expressing cells (Axin1flox/flox;Sox9-CreER), Col2a1-expressing cells (Axin1flox/flox;Col2a1-Cre), and Sp7-expressing cells (Axin1flox/flox;Sp7-Cre), suggesting that specific deficiency of Axin1 in Prrx1-expressing cell population is responsible for the FH development.