Three novel PHEX gene mutations in four Chinese families with X-linked dominant hypophosphatemic rickets.

Background: X-linked hypophosphatemia (XLH), the most common form of inherited rickets, is a dominant disorder that is characterized by renal phosphate wasting with hypophosphatemia, abnormal bone mineralization, short stature, and rachitic manifestations. The related gene with inactivating mutations associated with XLH has been identified as PHEX, which is a phosphate-regulating gene with homologies to endopeptidases on the X chromosome. In this study, a variety of PHEX mutations were identified in four Chinese families with XLH.

Methods: We investigated four unrelated Chinese families who exhibited typical features of XLH by using PCR to analyze mutations that were then sequenced. The laboratory and radiological investigations were conducted simultaneously.

Results: Three novel mutations were found in these four families: one frameshift mutation, c.2033dupT in exon 20, resulting in p.T679H; one nonsense mutation, c.1294A>T in exon 11, resulting in p.K432X; and one missense mutation, c.2192T>C in exon 22, resulting in p.F731S.

Conclusions: We found that the PHEX gene mutations were responsible for XLH in these Chinese families. Our findings are useful for understanding the genetic basis of Chinese patients with XLH.