CNNM2 and familial primary hypomagnesemia: Concerning the kidney expression of CNNM2, it is known that variants of human CNNM2 have been implicated in the development of Mg wasting syndrome (dominant hypomagnesemia), which support the role of CNNM2 as Mg transporter (Funato et al., 2017; Kolisek et al., 2019), whereas the deletion of the CNNM2 gene in the brain is associated with disturbed brain development and hypomagnesemia.