We demonstrated that the F727L mutation decreased the glycosylation level of PHEX protein, blocked PHEX protein transport from the ER to the plasma membrane, and reduced its activity to cleave FGF23 into inactive segments, which may explain why the single base substitution c.2179T>C led to the hypophosphatemic rickets in this Chinese family. This evidence concerns the gene FGF23 and hypophosphatemic rickets.