目的　对一婴儿型脊肌萎缩症家系进行产前基因诊断。方法　用 PCR-酶切技术对一家系孕 1 7w的风险胎儿进行 SMN基因外显子 7缺失的检测。结果　此风险胎儿无 SMN基因外显子 7缺失可继续妊娠。结论　婴儿型脊肌萎缩症可通过产前基因诊断避免患儿出生。 Objective To make a prenatal diagnosis of a pedigree of spondylarthillary atrophy. Methods The deletion of exon 7 of SMN gene was detected by PCR-restriction enzyme digestion in a fetus at risk of pregnancy. Results This risk fetus without SMN gene exon 7 deletion may continue pregnancy. Conclusion Infantile spinal muscular atrophy can prevent the birth of a child by prenatal genetic diagnosis.