α_1抗胰蛋白酶物质(α_1Antitrypsin,简称α_1AT)系一种由肝脏合成的糖蛋白,因其能抑制胰蛋白酶及其它蛋白分解酶而得名。它是血清α_1球蛋白的主要成分,生理作用尚不清楚,正常血清的含量约为200毫克％。在急性与慢性感染、肿瘤、妊娠以及服避孕药时,血清α_1AT含量增加,患特发性透明膜疾病的婴儿则减少。应用淀粉—明胶电泳及抗原—抗体交叉电泳方法证明,α_1AT有若干遗传变种,组成Pi(Protease inhibitor,蛋白酶抑制物)系统。迄今已鉴定出11个等位基因及21个表现型。大多数人为PiM基因纯合子(MM);少数人(2～12％)携带变种基因,其中部分人血清的α_1AT含量与MM表现型相比并无明显改变。与α_1AT缺乏有关的重要等位基因称 α_1 antitrypsin (α_1Antitrypsin, referred to as α_1AT) is a glycoprotein synthesized by the liver, because of its ability to inhibit trypsin and other proteolytic enzymes and named. It is the main component of serum α 1 globulin, the physiological role is not clear, the normal serum content of about 200 mg%. In acute and chronic infections, tumors, pregnancy and contraceptives, serum α_1AT levels increased, while those with idiopathic hyaline membrane disease decreased. Application of starch - gelatin electrophoresis and antigen - antibody cross - electrophoresis showed that α_1AT has a number of genetic variants, the composition of Pi (Protease inhibitor, protease inhibitor) system. So far, 11 alleles and 21 phenotypes have been identified. Most people are homozygous PiM gene (MM); a few people (2 ~ 12%) carry variant genes, some of which serum α_1AT content compared with the MM phenotype did not change significantly. An important allele related to the lack of α_1AT