Glossary

Acquired

An acquired disease is not contagious or inherited from a family member. It’s a disease you develop over time.

Anemia

A condition in which your body does not have enough hemoglobin (the part of your blood that carries oxygen). With anemia, you may have fewer whole red blood cells. This may cause you to feel weak and tired.

Aplastic anemia (AA)

“Aplastic” means that bone marrow can’t produce new blood cells properly. As a result, patients with aplastic anemia have fewer red blood cells, white blood cells, and platelets. PNH is often found along with aplastic anemia.

Blood clot

Blood clots form when parts of your body’s blood clump together. In a healthy body, this can stop bleeding when you’re cut or injured. But in certain conditions, these clumps can block blood flow in the veins and arteries, which can be dangerous. In PNH, a clot can happen at any time and can cause serious health problems.

Bone marrow

The soft tissue inside your large bones. It works to create the cells in your blood: red blood cells, white blood cells, and platelets.

Bone marrow failure disorder

A disorder that causes bone marrow to decrease or stop making blood cells. AA and MDS are bone marrow failure disorders.

Clone size

The percentage of blood cells in your body affected by PNH.

Complete blood count (CBC)

A lab test that gives the amounts of different cells in your blood.

Enzyme

A type of protein that helps reactions/processes happen in the body.

Erectile dysfunction (ED)

A condition found in men that affects their ability to achieve an erection.

Hemoglobin (Hgb)

The reddish-brown material found inside red blood cells. It carries oxygen throughout your body. When it gets outside of your cells, it is harmful and can lead to serious health problems.

Hemoglobinuria

Hemoglobin in the urine. About 25% of patients with PNH have it at diagnosis, but most will experience it at some time. Because of the reddish-brown color of hemoglobin, it results in dark, sometimes “cola-colored” urine.

Hemolysis

When red blood cells burst. Hemolysis is the main cause of the major health problems in PNH.

Lactate dehydrogenase (LDH)

An enzyme found in red blood cells, released during hemolysis. Testing for LDH can help show how much hemolysis is happening in your body.

Myelodysplastic syndromes (MDS)

A condition in which there’s a problem with the way bone marrow makes blood cells. About 2% of PNH patients also have MDS.

Paroxysmal nocturnal hemoglobinuria (PNH)

A disease where red blood cells are created without a protective protein. This causes them to burst (a process called hemolysis) and can result in serious health problems. Signs and symptoms include stomach pain, difficulty swallowing, anemia, shortness of breath, and tiredness. Life-threatening complications from PNH include blood clots, kidney failure, and damage to organs.

Progressive

A progressive disease is one that gets worse over time.

Pulmonary hypertension

High blood pressure in the arteries that deliver blood to the lungs. This means that blood has a hard time getting to the lungs, causing your heart to pump harder.

Red blood cells (RBCs)

A type of cell found in your blood that delivers oxygen and removes waste (carbon dioxide) in your body. Red blood cells affected by PNH are attacked and destroyed because they are missing a protective protein.

White blood cells (WBCs)

A type of cell found in your blood that helps your immune system fight disease and infection.