The proband's von Willebrand factor (VWF) antigen and VWF collagen-binding capacity were 14% and 10%, respectively; his sister's were 16% and 9%, respectively; and his nephew's were 30% and 15%, respectively. No apparent loss of high-molecular weight VWF multimers was observed in the plasma of these patients. A single-nucleotide substitution of T to C was found at nucleotide position 113042 in their VWF gene, converting Leu1733 to Pro in the A3 domain. These results suggest that p.Leu1733Pro is responsible for type 2M von Willebrand disease in this family.

中文翻译：

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在患有2M型von Willebrand疾病的家庭中，识别von Willebrand因子的A3结构域的错义突变（p.Leu1733Pro）。

先证者的von Willebrand因子（VWF）抗原和VWF胶原蛋白结合能力分别为14％和10％。他姐姐的分别是16％和9％；和他的侄子分别是30％和15％。在这些患者的血浆中未观察到高分子量VWF多聚体的明显损失。在其VWF基因的核苷酸位置113042处发现了T到C的单核苷酸取代，将Leu1733转化为A3域中的Pro。这些结果表明p.Leu1733Pro负责该家族的2M型von Willebrand疾病。