PHEX and X-linked hypophosphatemia: X-linked hypophosphatemia (XLH, OMIM 307800) is a rare genetic disease caused by inactivated variants in the PHEX gene, with an estimated prevalence of 1 in 20,000 individuals (phosphate-regulating gene with homologies to endopeptidase on the X chromosome, MIM #300550) (Carpenter, 1997; Guven et al., 2017; Rothenbuhler et al., 2020).