Abstract

Spinal muscular atrophy (SMA) is a neuromuscular disorder with an autosomal recessive inheritance pattern. Patients with severe symptoms may suffer respiratory failure, leading to death. The homozygous deletion of exon 7 in the SMN1 gene accounts for nearly 95% of all cases. Population carrier screening for SMA and prenatal diagnosis by amniocentesis for high-risk couples can assist in identifying the risk of fetal disease. We provided the SMA carrier screening process to 55,447 pregnant women in Yancheng from October 2020 to December 2022. Among them, 8185 participated in this process, with a participation rate of around 14.76% (95% CI 14.47–15.06%). Quantitative real-time polymerase chain reaction (qPCR) was used to detect deletions of SMN1 exons 7 and 8 (E7, E8) in screened pregnant women. 127 were identified as carriers (111 cases of E7 and E8 heterozygous deletions, 15 cases of E7 heterozygous deletions, and 1 case of E7 heterozygous deletions and E8 homozygous deletions), resulting in a carrying rate of around 1.55% (95% CI 1.30–1.84%). After genetic counseling, 114 spouses of pregnant women who tested positive underwent SMA carrier screening; three of them were screened as SMA carriers. Multiplexed ligation-dependent probe amplification (MLPA) was used for the prenatal diagnosis of the fetuses of high-risk couples. Two of them exhibited two copies of SMN1 exon 7 (normal), and the pregnancy was continued; one exhibited no copies of SMN1 exon 7 and exon 8 (SMA patient), and the pregnancy was terminated. Analyzing SMN1 mutations in Yancheng and provide clinical evidence for SMA genetic counseling and birth defect prevention. Interventional prenatal diagnosis for high-risk families can promote informed reproductive selection and prepare for the fetus’s early treatment.

中文翻译：

---

盐城地区孕妇脊髓性肌萎缩症携带者筛查及产前诊断

摘要

脊髓性肌萎缩症（SMA）是一种具有常染色体隐性遗传模式的神经肌肉疾病。症状严重的患者可能会出现呼吸衰竭，导致死亡。SMN1基因中外显子7的纯合缺失占所有病例的近95%。对高危夫妇进行 SMA 携带者筛查和羊膜穿刺产前诊断可以帮助识别胎儿疾病的风险。 2020年10月至2022年12月，我们为盐城55,447名孕妇提供了SMA携带者筛查流程。其中，8185人参与了这一流程，参与率约为14.76%（95% CI 14.47–15.06%）。采用实时定量聚合酶链反应 (qPCR) 检测筛选的孕妇中SMN1外显子 7 和 8（E7、E8）的缺失。 127例被鉴定为携带者（E7和E8杂合缺失111例，E7杂合缺失15例，E7杂合缺失和E8纯合缺失1例），携带率约为1.55%（95% CI 1.30– 1.84%）。经过遗传咨询，114名检测呈阳性的孕妇的配偶接受了SMA携带者筛查；其中三人被筛查为 SMA 携带者。多重连接依赖性探针扩增（MLPA）用于高危夫妇胎儿的产前诊断。其中两人表现出两个SMN1外显子7拷贝（正常），并继续妊娠；其中一名患者没有表现出SMN1外显子 7 和外显子 8的拷贝（SMA 患者），因此终止妊娠。分析盐城地区SMN1突变情况，为SMA遗传咨询和出生缺陷预防提供临床依据。对高危家庭进行介入性产前诊断，可以促进知情生殖选择，为胎儿的早期治疗做好准备。