What is Atypical Uremic Syndrome? 

Atypical hemolytic-uremic syndrome (aHUS) is a rare disease that affects multiple systems of the body, particularly the kidneys. Abnormal blood clots are formed in small blood vessels (capillaries), including those in the kidneys. This can make it difficult for the kidneys to work right and they may not be able to properly remove waste products from the blood. aHUS is characterized by three main features:

  • Hemolytic anemia: the red blood cells break down prematurely when they go through the capillaries (the smallest blood vessels in the body). This happens at higher frequency in the kidney capillaries. The anemia occurs when the red blood cells are destroyed at a rate faster than they are replenished.
  • Thrombocytopenia: a diminished number of platelets in the blood. The platelets are recruited and accumulate in the places where the red blood cells break down being less available in other parts of the body.
  • Kidney failure: the clots formed in the kidney capillaries can reduced the kidney filtration function and, eventually, lead to kidney failure.

aHUS is caused by a combination of genetic and environmental factors. Alterations of certain genes involved in the “complement system” can predispose to the development of the disease. The complement system is a group of proteins part of the immune system involved in fighting against foreign attacks and infections. Alterations of the genes that encode the proteins that shut down the complement system have been linked to a predisposition to develop aHUS. The complement system in people with aHUS does not function properly. There is usually a triggering event such as an infection that precedes the development of symptoms.  

Most of the cases of aHUS are sporadic, meaning that there is no family history of the disease.

How can RareShare be helpful to patients and families?As a free online disease-specific forum, RareShare can be a focal point where patients, families, researchers and healthcare providers can exchange information on Atypical Hemolytic Uremic Syndrome.

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