And this deficiency is called hemophilia A (or classic hemophilia).

这种缺乏症也称作血友病A（甲型血友病）或者经典血友病。

Alexei, the heir to the throne, had a life-threatening blood disease called hemophilia.

阿列克谢是王位的继承人，他得了血友病，这是一种可能会致死的血液疾病。

Today, we know that the doctors had prescribed aspirin, a drug that worsens hemophilia.

现今，我们知道那些医生开的处方是阿司匹林。这种药会让血友病恶化。

An insufficient concentration or decreased activity of any coagulation factor can cause hemophilia, except factor XII deficiency which is asymptomatic.

任何凝血因子的浓度不够或者活性降低都会引起血友病，一个例外是缺乏因子XII的话，不会有相关症状出现。

The youngest of five children, he was born with hemophilia (when blood doesn’t clot).

他是五个孩子中最小的一个， 生来就患有血友病（当血液不凝固时）。

He needs the fluid drained, but because of his hemophilia, I could kill him trying to save him.

他需要排出液体，但由于他患有血友病，我可以为了救他而杀了他。

Treatment for hemophilia A and B are done with injections of the missing or nonfunctional clotting factor.

治疗血友病A和B的方法通常是注射那些缺失或失活的凝血因子。

For hemophilia A, desmopressin, also called DDAVP (1-deamino-8-D-arginine vasopressin) is helpful for patients with mild, quantitative factor VIII deficiency.

对于血友病A，去氨加压素（DDAVP）有助于治疗轻症因子VIII数量缺乏。

Finally, it's best for individuals with hemophilia to avoid contact sports and medicines that promote bleeding, like aspirin.

最后对于血友病患者来说，最好避免接触性运动，不用促进血流的药物，如阿司匹林。

Believe it or not, this is a somewhat simplified version of the coagulation cascade; but, it contains all of the key parts needed to understand hemophilia.

总之，这就是简化版的凝血级联反应，已经包含了理解血友病病理所需的关键部分。