Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, chronic blood disease in which the body attacks and destroys its own red blood cells.

It’s caused by a change in the body’s DNA, known as a genetic mutation.

This change is acquired, meaning it happens randomly. It isn’t something you’re born with.

PNH causes red blood cells to be missing critical proteinsproteinsLarge, complex molecules that play many important roles in the body and can be thought of as the “workhorses” of cells. Proteins are required for the structure, function and regulation of the body’s organs and tissues. responsible for protecting them from attack by the immune systemimmune systemA sophisticated defense network used to protect the body from dangers like disease and infection..

Without these proteins, the immune system sees the red blood cells as foreign invaders, and attacks and destroys them.

When there are not enough red blood cells to carry oxygen around the body, the lack of oxygen causes many of the symptoms of PNH.

The symptoms are different for everyone, but can include fatigue, weakness, headaches, shortness of breath and other symptoms, including chest pain and abdominal pain.

There are treatments, but no cure.