Two novel PHEX mutations in Taiwanese patients with X-linked hypophosphatemic rickets

X-linked hypophosphatemic rickets (XLH) is an X-linked dominant disease characterized by renal phosphate wasting, hypophosphatemia, aberrant vitamin D metabolism, and defective bone mineralization. The disease is caused by mutations in the PHEX gene (phosphate-regulating gene with homologies to endopeptidases on the X-chromosome) located at Xp22.1. To date, a variety of PHEX mutations have been identified in these patients.

PCR and direct sequencing was performed for all exons and intron-exon boundaries of the PHEX gene in two XLH families.

Two novel mutations, including a missense mutation (L206W) in exon 5 and a frameshift mutation (nucleotide 1826_1830delAAAAG, stop after codon 610) in exon 18 were discovered and the laboratory and radiographic findings for these patients analyzed.

We found that PHEX gene mutations were responsible for XLH in these Taiwanese patients. Additional studies are needed to enhance understanding of the role of PHEX in XLH pathogenesis.