Analysis of phenotype and genotype in three Chinese pedigrees with glanzmann thrombasthenia / 中华检验医学杂志

ABSTRACT

Objective 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.