PNH

Paroxysmal nocturnal hemoglobinuria, commonly known as PNH, is a rare, acquired blood disorder. It is characterized by the destruction of red blood cells, a condition called hemolytic anemia. This destruction is caused by a defect in the bone marrow that produces blood cells. Specifically, PNH is caused by a mutation in the PIGA gene, which affects the production of a protein called GPI, anchoring. This protein normally protects blood cells from a part of the immune system called the complement system. Without GPI anchoring, red blood cells become susceptible to complement-mediated destruction, leading to their premature breakdown.

The symptoms of PNH can vary widely among individuals. Common signs include dark urine, especially noticeable in the morning, due to the presence of hemoglobin released from destroyed red blood cells. Fatigue, shortness of breath, abdominal pain, and difficulty swallowing are also frequently reported. Individuals with PNH may also experience an increased risk of blood clots, which can lead to serious complications such as strokes or pulmonary embolisms. The severity and specific manifestations of the disease depend on the extent of red blood cell destruction and the presence of other complications.

Diagnosis of PNH typically involves blood tests to assess for anemia and evidence of hemolysis. A flow cytometry test is the definitive diagnostic method, as it can identify the absence of GPI-anchored proteins on blood cells. Treatment for PNH aims to manage symptoms, prevent complications, and improve quality of life. Historically, treatments focused on supportive care. However, newer therapies, such as complement inhibitors, have revolutionized PNH management by directly targeting the underlying mechanism of red blood cell destruction. In some cases, a stem cell transplant may be considered as a curative option.