红细胞生成性原卟啉病一家系中亚铁螯合酶基因突变的检测

FECH gene mutation in a Chinese family with erythropoietie protoporphyria

目的对一红细胞生成性原卟啉病（EPP）家系进行基因突变研究，探讨基因突变与临床表现的关系，为进一步开展基因诊断和基因治疗奠定基础。方法收集家系资料，抽取家系中患者、正常人及与该家系无关的50例正常人的外周血，提取外周血基因组DNA。应用PCR方法扩增外周血基因组DNA亚铁螯合酶（FECH）基因的第1至11外显子及其侧翼序列。PCR产物直接进行双向测序以检测突变。结果根据临床表现和卟啉测定结果，患者明确诊断为红细胞生成性原卟啉病。PCR扩增得到预期DNA片段。PCR产物直接测序结果：家系中先证者、其妹和其父FECH基因第1内含子供体剪接位点检测到一个杂合突变（IVS1＋1G→C），该突变为国际首次报道。还在先证者、其妹和其母FECH基因第1内含子受体端检测到一个与低表达等位基因相关的多态性（IVS1—23C／T）。结论报道一FECH基因第1内含子供体剪接位点的新突变，该突变可能引发FECH基因缺陷，是EPP家系中患者发病的分子基础。

Objective To investigate the FECH gene mutation in a Chinese family with erythropoietic protoporphyria, to explore the relationship between gene mutation and clinical manifestations so as to establish a basis for the genetic diagnosis and treatment of erythropoietic protoporphyria. Methods Clinical data on a Chinese family with typical EPP was collected. Peripheral blood was obtained from patients, unaffected individuals in the family and 50 unrelated human controls. Genomic DNA was extracted and PCR was performed to amplify the whole coding regions （exons 1 to 11 ） of FECH gene and their flanking intron sequences followed by direct sequencing to detect possible mutations. Results Based on clinical symptom and porphyrin levels, a diagnosis of erythropoietic protoporphyria was made in 3 family members. DNA fragments of expected size were amplified by PCR. Gene sequencing revealed a heterozygous mutation （IVS1 ＋ 1G 〉 C） in intron 1 of FECH gene in the proband, his sister and father, but not in unaffected family members or unrelated human controls. Also, an IVS1-23C/T polymorphism associated with low expression alleles was observed in intron 1 of FECH gene of the proband, his sister and mother. Conclusions A novel mutation in the donor splice site of intron 1 of FECH gene is first reported in a Chinese family with EPP; this muta- tion may lead to a deficiency of FECH gene and serve as a molecular basis of development of erythropoietic protoporphyria.