目的总结1例罕见的STR基因座突变。方法应用多位点复合PCR扩增技术及聚丙烯酰胺凝胶电泳分型技术,对亲子鉴定案例进行分析。结果 STR基因座D18S51和D8S1179同时发生遗传突变且D18S51基因座发生两步突变。结论亲子鉴定过程中,若只有1个或2个STR基因座违反孟德尔遗传规律时,若为单亲鉴定则加测孩子生母STR基因座分型,若为双亲鉴定赢增加遗传标记,综合分析以排除或认定亲子关系。 Objective To summarize a rare case of STR locus mutation. Methods Multi-site multiplex PCR amplification and polyacrylamide gel electrophoresis typing were used to analyze the paternity test cases. Results Both STR loci D18S51 and D8S1179 were mutated at the same time and D18S51 locus was mutated in two steps. Conclusion If there is only one or two STR loci that violate Mendelian inheritance in paternity testing, if the single parents are identified, the genotypes of the STR loci of the children are added. If genetic markers are added to the identification of parents, Exclude or identify parent-child relationship.