CNNM4 and Jalili syndrome: CNNM4 has low expression in the kidney (collecting ducts and proximal tubules, HPA) but seems critical for Mg2+ absorption in the intestine as shown by its involvement in Jalili syndrome [106] (Figs. 2C and 7B); CNNM1 and − 2 are also expressed in different parts of the intestinal tract, while CNNM1 is found to be important in brain and testis [107].