婴儿脊髓性肌萎缩症1c型1例的遗传学分析

Genetic analysis of a case of infant spinal muscular atrophy type 1c

目的总结脊髓性肌萎缩症1c型1例患儿的遗传学特点。方法回顾性分析1例脊髓性肌萎缩症1c型患儿的病例资料,对其进行遗传学分析并文献复习。结果患儿,男,2月龄起病,表现为粗大运动发育落后、肌张力低。多重连接探针扩增技术显示患儿SMN1基因外显子7-8纯合缺失突变,SMN2基因外显子7-8存在重复突变,外显子7/8拷贝数为3/3,其父亲为SMN1基因杂合缺失携带者,SMN2基因8外显子存在纯合突变,外显子7/8拷贝数为2/3,其母亲未发现SMN1基因外显子异常,SMN2基因外显子7/8拷贝数为1/1。结论脊髓性肌萎缩症在早期缺乏特异表现,确诊主要依赖于基因检测,临床医师需要提高警惕,加强对该病的早期认识,改善预后。

Objective To summarize the genetic characteristics of a case of spinal muscular atrophy type 1c.Methods The case data of a child with spinal muscular atrophy type 1c was retrospectively analyzed,and the genetic analysis and literature review were carried out.Results The patient,male,started at the age of 2 months,and showed gross motor development backwardness and low muscular tension.Multiplex connection probe amplification technique showed that the child had homozygous deletion mutation in exon 7-8 of SMN1 gene,and there was duplicate mutation in exon 7-8 of SMN2 gene.The number of copies of exon 7/8 was 3/3.His father was a heterozygous deletion carrier of SMN1 gene,and there was homozygous mutation in exon 8 of SMN2 gene.The number of copies of exon 7/8 was 2/3.His mother did not find abnormal exons of SMN1 gene,and the number of copies of exon 7/8 of SMN2 gene was 1/1.Conclusion Spinal muscular atrophy lacks specific manifestations in the early stage,and the diagnosis mainly depends on genetic testing.Clinicians need to be vigilant,strengthen the early understanding of the disease,and improve the prognosis.