摘要目的 对3个遗传性血小板无力症(glanzmann thrombasthenia,GT)家系进行血小板膜糖蛋白Ⅱ b、Ⅲa(GPⅡb/GPⅢa)基因突变的检测.方法 应用PCR对先证者GPⅡb/GPⅢa基因所有外显子及其侧翼序列进行扩增;PCR产物纯化后直接测序,检测其突变基因.突变位点经直接测序证实排除基因多态性.结果 3个家系的先证者PLT均正常,血小板形态分散,出血时间(BT)延长,凝血象正常,对二磷酸腺苷(ADP)、凝血酶、.肾上腺素、胶原、花生四烯酸等多种诱聚剂反应低下,而对瑞斯托霉素反应基本正常;家系1和家系2先证者的血小板膜表面CD41(GPⅡ b)/CD61(GPⅢa)的含量极度降低,分别为0.16%/1.8%、0.9%/3.7%,家系3先证者的血小板膜表面GP Ⅱ b阳性血小板为10.1%,GPⅢa阳性血小板为12.8%.免疫印迹法几乎检测不到家系1和家系3先证者的αⅡb蛋白,家系2先证者的αⅡb蛋白含量明显降低.家系1先证者在GP Ⅱ b基因存在T2255G和C2671T复合杂合突变,家系2先证者在GPⅡb基因存在A2334C纯合突变,家系3先证者在GP Ⅱ b基因存在C1750T和69-79del复合杂合突变.结论 T2255G和C2671T复合杂合突变是导致家系1先证者发生GT的原因,A2334C纯合突变是导致家系2先证者发生GT的原因,C1750T和69-79 del复合杂合突变是导致家系3先证者发生GT的原因.

abstractsObjective To identify the gene mutations of platelet membrane glycoprotein Ⅱ b,Ⅲa(GPⅡb/Ⅲa)in three Chinese pedigrees with Glanzmann thrombastIlenia.Methods All exons and exonintron boundaries of GP Ⅱ b/Ⅲ a gene were amplified by PCR analysis followed by DNA sequencing.DNA sequencing was used to exclude gene polymorphisms.Results The probands in the three pedigrees had a normal platelet count,coagulation profiles,scattered platelets on the blood film,a prolonged cutaneous bleeding time,and impaired or minimal ex vivo platelet aggregation in response to ADP,thrombin,collagen,adrenaline and arachidonic acid,but normal platelet aggregation in response to ristoeetin.Both FACS and Western blotting demonstrated trace content of αⅡb in the platelets from proband 1 and proband 3,who were classified as type Ⅰ GT,and a small amount of αⅡb in the platelets from proband 2,who was classified as type Ⅱ GT.Compound heterozygous mutations,T2255G(Leu721Arg)and C2671T(Gln860Stop)were identified in proband 1.The proband 2 had homozygous A2334C(Gln747Pro)missense mutation.Nonsense mutations C1750T (Arg584Stop)and 69-79 deletion mutation were identified in proband 3. Conclusions Compound heterozygous mutations T2255G and C2671T of αⅡb gene lead to type Ⅰ Glanzmann thrombasthenia for proband 1. Homozygous mutation A2334C of αⅡb gene leads to type Ⅱ Glanzmann thrombasthenia for proband 2. Compound heterozygous mutations C1750T and 69-79del αⅡb gene lead to type Ⅰ Glanzmann thrombasthenia for proband 3. T2255G,C1671T and 69-79del aye novel mutations for αⅡb gene.