一个脊髓性肌萎缩症的家系报道

A pedigree report of spinal muscular atrophy

目的 对一个生育过脊髓性肌萎缩症患儿的家系进行产前诊断,同时对三种实验室检测技术进行方法学的比较。方法 应用荧光定量PCR、荧光PCR-毛细管电泳法及MLPA对家系外周血样本及绒毛组织、羊水组织进行了检测。同时进行了亲缘鉴定以排除母源污染。结果 第一胎患儿为SMN1基因7、8号外显子纯合缺失合并SMN2基因的3拷贝重复,患儿父亲为SMN1基因第7、8号外显子的杂合缺失携带者合并SMN2基因的3拷贝重复,患儿母亲为SMN1基因第7、8号外显子的杂合缺失携带者,SMN2基因2拷贝。本次妊娠胎儿为SMN1基因第7、8号外显子杂合缺失及SMN2基因3拷贝重复。结论 经检测胎儿仅为SMN1基因杂合缺失的携带者,可继续正常妊娠。同时,荧光PCR-毛细管电泳法和MLPA可同时对SMN1和SMN2基因拷贝数进行检测,检测较为全面,但荧光定量PCR检测操作方便,检测周期短,适合大样本人群的普筛。

Objective To diagnose a family with spinal muscular atrophy in a prenatal manner and to compare the methodologies of three laboratory testing techniques.Methods Fluorescence quantitative PCR,fluorescent PCR-capillary electrophoresis and MLPA were used to detect family peripheral blood samples,chorionic villus tissue and amniotic fluid tissue.Affinity was also performed to rule out maternal contamination.Results The first child had homozygous deletion of exons 7 and 8 of SMNI gene,combined with 3 copies of SMN2 gene,the father of the child was a heterozygous deletion carrier of exons 7 and 8 of SMNl gene with 3 copy duplication of SMN2 gene,and the mother was a heterozygous deletion carrier of exons 7 and 8 of SMNI gene,and 2 copy duplication of SMN2 gene.The fetus is heterozygous deletion of exons 7 and 8 of SMNI gene and 3 copy duplication of SMN2 gene.Conclusion After testing,the fetus is only a carrier of heterozygous deletion of SMNl gene,and the mother can continue to have a normal pregnancy.At the same time,fluorescent PCR-capillary electrophoresis and MLPA can detect SMNI and SMN2 gene copy numbers at the same time,and the detection is relatively comprehensive,but the fluorescence PCR detection is convenient to operate,the detection cycle is short,and it is suitable for general screening of large sample populations.