Blood groups are inherited, and Rhnull is known to run in families.

血型是由遗传决定的，Rhnull血型同样如此。

Rhnull blood was first found in 1961 in an Australian woman.

1961年，Rhnull血型在一名澳大利亚妇女身上首次被发现。

But, by 2010, nearly five decades later, some 43 people with Rhnull blood had been reported worldwide.

但是，在大约50年以后的2010年，世界范围内大约有43人拥有Rhnull血。

In reality, because Rhnull blood is so rare, it is also extremely dangerous to live with.

在现实中，因为Rhnull血非常罕见，拥有这种血型也是一件极其危险的事。

Because fewer than 50 individuals in the entire world have the Rhnull blood type, finding a blood donor for Rhnull individuals can be nearly impossible.

因为全世界只有不到50个人拥有Rhnull血型，为Rhnull血型的人找到一个献血者几乎是不可能的事情。

As Rhnull blood contains no Rh antigens to be rejected, it can be a universal donor for those with generally rare blood types.

由于Rhnull型的血液不含会被排斥的Rh抗原，它可以为那些拥有罕见血型的人提供通用供体。

This means if you have the Rhnull blood type, receiving a transfusion of a blood type with any Rh antigens will cause your body to reject the blood.

这也就意味着，如果你是Rhnull血型，接受任何带有Rh抗原的血型输血都会导致你的身体排斥这种血液。

But, as the name implies, the Rhnull blood type is completely missing these Rh blood group antigens, which makes it the rarest blood type in the world.

但是，正如该血型名字所暗示的那样，Rhnull血型便没有这些Rh血型抗原，这使它成为世界上最罕见的血型。