OBJECTIVETo explore the molecular basis for three pedigrees affected with hypophosphatemia vitamin D resistant rickets (X-linked hypophosphatemia, XLH).

METHODSPeripheral blood samples from the three pedigrees were collected. Following DNA extraction, the 11 exons and flanking regions of the PHEX gene were subjected to PCR amplification and direct sequencing. Pathogenicity of identified mutations was evaluated through genotype-phenotype correlation.

RESULTSFor pedigrees 1 and 2, pathogenic mutations were respectively identified in exon 8 (c.871C>T, p.R291X) and exon 15 (c.1601C>T, p.P534L) of the PHEX gene. For pedigree 3, a novel mutation (c.1234delA, p.S412Vfs*12) was found in exon 11 of the PHEX gene, which caused shift the reading frame and premature termination of protein translation.

CONCLUSIONThe three mutations probably account for the XLH in the affected pedigrees. The discovery of novel mutations has enriched the spectrum of PHEX gene mutations.