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

摘要： 家族性低磷血症性佝偻病（FHR）是罕见的遗传性佝偻病，由一组以肾脏磷酸盐运输缺陷导致排泄磷酸盐过多和低血磷为特征的疾病组成，其中最常见的类型为X-连锁显性遗传佝偻病（XLH）。XLH为X染色体内肽酶同源性的磷酸调节基因（PHEX基因）突变引起，发病率约为1/20 000，临床主要表现为不成比例的身材矮小、佝偻病、下肢畸形、血磷低，而血钙处于参考范围。本文报道了1个FHR家系的先证者及其主要家族成员，并进行基因测序，发现该家系中4例患者均有PHEX基因c.2066C>T（p.Ala689Val）杂合子突变，该突变为错义突变，且ESP6500、dbSNP、千人基因组数据库中均未收录该突变，为该家系的遗传咨询和今后的产前诊断提供依据。

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