目的　研究我国Ⅰ～Ⅳ型脊髓性肌萎缩症 (SMA)患者运动神经元生存基因 (SMN)及神经细胞凋亡抑制蛋白 (NAIP)基因外显子的缺失情况 ,以探讨此两种基因与SMA表型之间的关系。方法　应用PCR法检测 45例Ⅰ～Ⅳ型SMA患者、30例表型正常的SMA直系亲属及 30例正常对照的SMN基因第 7、8号外显子和NAIP基因第 5、6号外显子缺失情况。结果　 7例Ⅰ型和Ⅱ型SMA患者中 6例纯合缺失SMN基因外显子 7和 8,1例纯合缺失外显子 7而保留外显子 8;8例Ⅲ型SMA患者仅1例缺失外显子 7和 8,余 7例均无SMN基因的缺失 ;成人型 (Ⅳ型 )SMA未检测到SMN基因缺失 ;45例Ⅰ～Ⅳ型SMA患者均未检测到NAIP基因外显子 5和 (或 ) 6的缺失。结论　Ⅰ型、Ⅱ型SMA可通过SMN基因第 7、8号外显子的检测进行确诊 ,Ⅲ型SMA患者SMN基因缺失率低 ,故通过检测SMN基因 7、8外显子进行基因诊断尚需谨慎 ,Ⅳ型SMA未检测到SMN基因缺失 ,发病可能与SMN基因缺失无关 ;NAIP基因在SMA发病中的作用尚不清楚 Objective To investigate the deletion of exon of motor neuron survival gene (SMN) and neuronal apoptosis inhibitor protein (NAIP) in patients with type Ⅰ-Ⅳ spinal muscular atrophy (SMA) Relationship between phenotypes. Methods The deletion of exon 7 and exon 7 of SMN gene and exon 5 and exon 5 of NAIP gene in 45 patients with type Ⅰ ~ Ⅳ SMA, 30 normal normal SMA relatives and 30 normal controls were detected by PCR. . Results Of the 7 type Ⅰ and type Ⅱ SMA patients, 6 homozygous deletion of SMN exon 7 and 8, 1 homozygous deletion of exon 7 retained exon 8; 8 type Ⅲ SMA patients only 1 case No deletion of SMN gene was found in the remaining 7 cases with deletion of exons 7 and 8. No deletion of SMN gene was detected in adult type Ⅳ SMA. None of 45 cases with type Ⅰ ~ Ⅳ SMA detected NAIP exon 5 And / or 6 deletions. Conclusion The type Ⅰ and type Ⅱ SMA can be diagnosed by detecting the exon 7 and exon 8 of SMN gene. The deletion rate of SMN gene in type Ⅲ SMA patients is low. Therefore, it is necessary to be cautious in gene diagnosis by detecting exons 7 and 8 of SMN gene , SMN gene deletion was not detected in type IV SMA, and the incidence of SMN gene may not be related to the deletion of SMN gene; the role of NAIP gene in the pathogenesis of SMA is unclear