Hilbert L, Gaucher C, Abgrall J F, Parquet A, Trzeciak C, Mazurier C
LFB, Lille, France.
Br J Haematol. 1998 Dec;103(3):877-84. doi: 10.1046/j.1365-2141.1998.01040.x.
We report the identification in five patients (three families) affected with type 2B von Willebrand disease (VWD) of three heterozygous nucleotide substitutions at the codon for arginine 543, 545 and 578 of the mature von Willebrand factor (VWF) subunit resulting in a glutamine, proline and leucine substitution, respectively. These mutations are located in the A1 loop where prevalent type 2B mutations (Arg543Trp, Arg545Cys and Arg578Gln) have been already identified at the same positions. By in vitro mutagenesis of full-length cDNA of VWF and transient expression in Cos-7 cells, we have shown that the six corresponding mutated recombinant VWFs (Gln543, Trp543, Cys545, Pro545, Leu578 and Gln578 rVWF) exhibited quantitatively normal expression and normal multimeric pattern but increased ristocetin- and botrocetin-induced binding to platelets as compared with that for wild-type rVWF. The two mutations at position 545 induced the greatest reactivity for GPIb of corresponding rVWFs as compared to the two mutations at positions 543 and 578.
我们报告了在5例（3个家系）2B型血管性血友病（VWD）患者中，成熟血管性血友病因子（VWF）亚基精氨酸543、545和578密码子处存在3个杂合核苷酸替代，分别导致谷氨酰胺、脯氨酸和亮氨酸替代。这些突变位于A1环，在相同位置已发现常见的2B型突变（精氨酸543色氨酸、精氨酸545半胱氨酸和精氨酸578谷氨酰胺）。通过对VWF全长cDNA进行体外诱变并在Cos-7细胞中瞬时表达，我们发现6种相应的突变重组VWF（谷氨酰胺543、色氨酸543、半胱氨酸545、脯氨酸545、亮氨酸578和谷氨酰胺578重组VWF）表达量正常且多聚体模式正常，但与野生型重组VWF相比，瑞斯托霉素和蛇毒凝血酶诱导的与血小板的结合增加。与543和578位的两个突变相比，545位的两个突变诱导相应重组VWF对糖蛋白Ib（GPIb）的反应性最强。
