一例血色病患者及其家系铁代谢调节基因的突变分析

目的对1名临床诊断怀疑为原发性血色病的患者及家属进行血色病相关基因检测。方法记录患者临床资料,采集患者及家属外周血,检测血清铁(SI)、总铁结合力(TIBC)、铁蛋白(SF)和转铁蛋白饱和度(TS);提取血液基因组DNA,采用聚合酶链反应(PCR)扩增铁代谢调节基因HFE、HJV、HAMP、TFR2、SLC40A1的外显子、内含子剪切序列及5'、3'端非翻译区域(UTR),琼脂糖凝胶电泳、纯化后,双向直接测序检测突变位点。结果患者SF、SI、TS明显升高。TFR2 exon2中出现c.224CT杂合突变(p.Ala75Val错义突变),exon5中出现c.714CG杂合突变(p.Ile238Met错义突变);SLC40A1 exon6中出现c.663TC纯合突变(p.Val221Val同义突变)。HFE、HAMP、HJV未检测到突变。家属成员中未见上述TFR2突变,皆存在SLC40A1 V221V突变。结论 TFR2 A75V和I238M突变可能是该名血色病患者发病的遗传基础,其机制有待于进一步研究。

Mutation analysis of iron metabolism regulated genes in a patient of hemochromatosis

Objective To detect the mutation of hemochromatosis-related gene in a patient suspected with hereditary hemochromatosis and his family members.Methods The peripheral blood samples were collected from the patient and his family members after recording patient′s clinical data.The indices of iron metabolism including serum iron （SI）,total iron binding capacity （TIBC）,serum ferritin （SF）and transferrin saturation （TS）were determined. The genomic DNA from peripheral blood was isolated,and polymerase chain reaction （PCR）was used to amplify exon and intron splice junctions,and the 5′and 3′untranslated regions （UTRs）of HFE,HJV,HAMP,TFR2 and SLC40A1 genes.After agarose gel electrophoresis and purification,the PCR products were submitted to bidirectional sequence analysis for determining mutation.Results SF,SI and TS increased significantly in the patient.Mutation analysis in the patient revealed c.224C 〉T （p.Ala75Val）and c.71 4C 〉G （p.Ile238Met）heterozygous mutations respectively located in exon2 and exon5 of TFR2.Additional synonymous mutation was also found in exon6 of SLC40A1 （c.663T〉C,p.Val221 Val）.There was no mutation being found in HFE,HAMP and HJV in the patient.SLC40A1 V221 V mutation was all detected in the patient′s family members,but it did not happen to the aforementioned TFR2 mutations. Conclusions TFR2 A75V and I238Mmutations may be the genetic basis of hereditary hemochromatosis in this patient, but its pathogenic mechanism remains to be further studied.