Normally, the liver and kidneys produce a tiny hormone called thrombopoietin which binds to hematopoietic cell receptors.

正常情况下，肝脏和肾脏会合成一种叫做促血小板成素的激素，可以与造血胞受体结合。

Cells can also develop mutations in the thrombopoietin receptor, MPL, or in the chaperone protein, Calreticulin or CalR.

胞内的促血小板成素受体（MPL）或伴侣蛋白/钙网蛋白（CalR）也可以变。

Now, when there's a genetic mutation in CalR, the signalling pathway remains active all the time, and that means that platelets keep getting produced even in the absence of thrombopoietin.

在CalR基因变后，信号通路处于持续激活状态，这就意味着即使没有促血小板成素，血小板也会持续成。