Miyata T, Zheng Y Z, Sakata T, Tsushima N, Kato H
Laboratory of Thrombosis Research, National Cardiovascular Center Research Institute, Suita, Japan.
Thromb Haemost. 1994 Jan;71(1):32-7.
We have studied the molecular basis of protein C deficiency in three families with a history of thromboembolic disease. An approximately 50% reduction in both functional and immunologic levels of protein C was detected in the plasma from two unrelated patients, designated protein C Osaka 1 and protein C Osaka 2. An approximately 50% reduction in functional level but normal immunologic level of protein C was detected in plasma from a third patient, designated protein C Osaka 3. DNA sequencing of the amplified DNA revealed one missense mutation in each case. Additional mutations in the coding sequence were excluded by DNA sequencing of all protein C exons. We identified a C-to-T change at nucleotide number 6,218 of the protein C gene in protein C Osaka 1. This results in the amino acid substitution of Arg-169 by Trp at the alpha-thrombin cleavage site. In protein C Osaka 2, a G-to-A change at nucleotide number 8,807 was identified leading to the amino acid substitution of Met-364 by Ile in the protease domain. This substitution may impair the synthesis or stability of protein C Osaka 2. In protein C Osaka 3, a G-to-C change at nucleotide number 8,868 was identified. This results in substitution of Gly-385 by Arg in the protease domain. Based on these, it was concluded that Arg-169-to-Trp mutation and Met-364-to-Ile mutation cause type I protein C deficiency and Gly-385-to-Arg mutation causes type II deficiency.
我们研究了三个有血栓栓塞性疾病病史的家族中蛋白C缺乏的分子基础。在两名无亲缘关系的患者（分别命名为蛋白C大阪1型和蛋白C大阪2型）的血浆中，检测到蛋白C的功能水平和免疫水平均下降了约50%。在第三名患者（命名为蛋白C大阪3型）的血浆中，检测到蛋白C的功能水平下降了约50%，但免疫水平正常。对扩增DNA进行的DNA测序显示，每种情况下均有一个错义突变。通过对所有蛋白C外显子进行DNA测序，排除了编码序列中的其他突变。我们在蛋白C大阪1型中鉴定出蛋白C基因第6218位核苷酸处的C到T变化。这导致在α-凝血酶切割位点处，精氨酸-169被色氨酸取代。在蛋白C大阪2型中，鉴定出第8807位核苷酸处的G到A变化，导致蛋白酶结构域中的甲硫氨酸- 364被异亮氨酸取代。这种取代可能会损害蛋白C大阪2型的合成或稳定性。在蛋白C大阪3型中，鉴定出第8868位核苷酸处的G到C变化。这导致蛋白酶结构域中的甘氨酸-385被精氨酸取代。基于这些结果，得出结论：精氨酸-169到色氨酸突变和甲硫氨酸-364到异亮氨酸突变导致I型蛋白C缺乏，甘氨酸-385到精氨酸突变导致II型缺乏。
