关键词: 低磷血症性佝偻病, X连锁显性；X染色体内肽酶同源性的磷酸调节基因；突变

Abstract: Familial hypophosphatemic rickets is a rare hereditary rickets representing a group of diseases characterized by excessive phosphate excretion and hypophosphatemia caused by defects of renal phosphate transport.The most common form of the disorder is X-linked hypophosphatemic rickets（XLH），which has an X-linked dominant inheritance.XLH is caused by the PHEX gene mutation and has an incidence of 1/20 000.The clinical manifestations of the disease include disproportionate short stature，rickets，lower extremity deformity，hypophosphatemia，and normal serum calcium.In this study，we reported an XLH family and performed sequencing analyses on the proband and main family members.We found that a c.2066C>T（p.Ala689Val） heterozygous missense mutation of the PHEX gene occurred in four family members，moreover，the variation had not been included in the ESP6500，dbSNP，and 1 000 genomes databases.Our finding provides valuable information for genetic counseling and prenatal diagnosis of the disease.

Key words: Hypophosphatemic rickets, X-linked dominant；Phosphate-regulating gene with homologies to endopeptidase on the X-chromosome；Mutation