Abstract：
OBJECTIVE: To analyze variants of SMN gene in a Chinese pedigree affected with Spinal muscular atrophy (SMA).
METHODS: A Chinese pedigree diagnosed at the Nanchang First Hospital in January 2020 was selected as the study subject. Peripheral blood samples were collected for the extraction of DNA. All exons of the SMN gene were detected by multiple ligation-dependent probe amplification (MLPA). Potential variants of the SMN gene were also detected by Whole exome sequencing (WES), and the result was verified by Sanger sequencing. cDNA extracted from fresh blood sample was used as a template to verify the location of variant on the SMN genes.
RESULTS: The proband was found to harbor a heterozygous deletion of the SMN1 Exon7+Exon8, and a heterozygous c.81G>A variant. The SMN1 Exon7+Exon8 deletion was inherited from her father and grandmother, whilst the c.81G>A variant was inherited from her mother and maternal grandfather. Her aunt was also a carrier of the heterozygous deletion, while her paternal aunt, her husband, and their daughter were not. cDNA amplification and Sanger sequencing confirmed that the c.81G>A variant was located in the SMN1 gene.
CONCLUSIONS: MLPA combined with NGS and Sanger sequencing can identify compound heterozygous variants of the SMN gene in the SMA patients.
METHODS: A Chinese pedigree diagnosed at the Nanchang First Hospital in January 2020 was selected as the study subject. Peripheral blood samples were collected for the extraction of DNA. All exons of the SMN gene were detected by multiple ligation-dependent probe amplification (MLPA). Potential variants of the SMN gene were also detected by Whole exome sequencing (WES), and the result was verified by Sanger sequencing. cDNA extracted from fresh blood sample was used as a template to verify the location of variant on the SMN genes.
RESULTS: The proband was found to harbor a heterozygous deletion of the SMN1 Exon7+Exon8, and a heterozygous c.81G>A variant. The SMN1 Exon7+Exon8 deletion was inherited from her father and grandmother, whilst the c.81G>A variant was inherited from her mother and maternal grandfather. Her aunt was also a carrier of the heterozygous deletion, while her paternal aunt, her husband, and their daughter were not. cDNA amplification and Sanger sequencing confirmed that the c.81G>A variant was located in the SMN1 gene.
CONCLUSIONS: MLPA combined with NGS and Sanger sequencing can identify compound heterozygous variants of the SMN gene in the SMA patients.
摘要：
目的：分析患有脊髓性肌萎缩症（SMA）的中国家系中SMN基因的变异。
方法：选取2020年1月在南昌市第一医院确诊的中国家系作为研究对象。收集外周血样品用于提取DNA。通过多重连接依赖性探针扩增(MLPA)检测SMN基因的所有外显子。SMN基因的潜在变异也通过全外显子组测序（WES）检测，并通过Sanger测序验证结果。将从新鲜血液样品中提取的cDNA用作模板以验证变体在SMN基因上的位置。
结果：发现先证者具有SMN1Exon7Exon8的杂合缺失和杂合的c.81G>A变体。SMN1Exon7+Exon8删除是从她的父亲和祖母那里继承的，而c.81G>A变体是从她的母亲和外祖父那里继承的。她的姑姑也是杂合缺失的携带者，而她的姑姑,她的丈夫,他们的女儿没有。cDNA扩增和Sanger测序证实c.81G>A变体位于SMN1基因中。
结论：MLPA联合NGS和Sanger测序可以在SMA患者中鉴定SMN基因的复合杂合变体。
方法：选取2020年1月在南昌市第一医院确诊的中国家系作为研究对象。收集外周血样品用于提取DNA。通过多重连接依赖性探针扩增(MLPA)检测SMN基因的所有外显子。SMN基因的潜在变异也通过全外显子组测序（WES）检测，并通过Sanger测序验证结果。将从新鲜血液样品中提取的cDNA用作模板以验证变体在SMN基因上的位置。
结果：发现先证者具有SMN1Exon7Exon8的杂合缺失和杂合的c.81G>A变体。SMN1Exon7+Exon8删除是从她的父亲和祖母那里继承的，而c.81G>A变体是从她的母亲和外祖父那里继承的。她的姑姑也是杂合缺失的携带者，而她的姑姑,她的丈夫,他们的女儿没有。cDNA扩增和Sanger测序证实c.81G>A变体位于SMN1基因中。
结论：MLPA联合NGS和Sanger测序可以在SMA患者中鉴定SMN基因的复合杂合变体。
