CaSR expression (Fig. 4b) appeared slightly suppressed in the CKD groups, but was not affected by genetic deletion of Fgfr1–3, Fgfr1–4, or αKlotho. VDR expression (Fig. 4c) was not affected by the status of kidney function or the genetic deletions in our model. Here, FGFR1 is linked to chronic kidney disease.