What is atypical-HUS

Atypical hemolytic uremic syndrome (atypical-HUS) is a rare, life-threatening, genetic diseaseGenetic disease is a disease caused by a genetic mutation, or change, in DNA.13 of uncontrolled complement activation that affects as many adults as it does children.1,4

It may lead to the damage of vital organs.2

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What causes atypical-HUS?

In atypical-HUS, the complement systemComplement system is a natural part of the immune system that helps protect the body from foreign substances like bacteria or other infections. The complement system is made up of a group of proteins found in the blood.5, which is part of the immune system, is uncontrolled. It is always on and can attack the body it normally protects.2,3,5

Damage from the uncontrolled complement system is known as systemic thrombotic microangiopathy (TMA)Thrombotic microangiopathy (TMA) is a disorder that results in clots and inflammation in various small blood vessels throughout the body due to an endothelial injury.13,19. If your complement system is uncontrolled, cells along blood vessel walls become damaged. PlateletsPlatelets (or thrombocytes) are blood cells whose function is to help the blood clot to stop bleeding.15 become overactive and blood clots form in tiny blood vessels throughout the body. Clots can block blood flow, create inflammation, and travel to other organs, causing further damage.2,3,6

The uncontrolled complement part of the immune system causes abnormal clotting and inflammation, resulting in damage to tiny blood vessels3

The damage that occurs throughout the body is known as TMA, which can lead to problems in kidneys and other vital organs2,3,7

“When I was first diagnosed with aHUS, I wasn’t sure what to do. Finding the right resources, team, and support network helped me feel like I wasn’t alone.”

– Patient diagnosed with atypical-HUS

How do you get atypical-HUS?

Atypical-HUS is caused by a change, or mutationMutation is a permanent change in the DNA sequence that makes up a gene. Genes code for proteins, so changes that occur in the DNA sequence can lead to proteins that do not function properly.14, in the genes that produces the proteins that help control the immune system. Because atypical-HUS is caused by a genetic mutation, it is classified as a chronic disease. Testing for specific genes is not necessary for your doctor to diagnose you with atypical-HUS, and the absence of a genetic mutation does not rule out atypical-HUS.1-4

The underlying cause of the disease is always present and the risk of sudden, damaging symptoms is constant.1

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of people with atypical-HUS do not currently have mutations that show up in genetic tests.4,8

“It does get better. It’s scary at first, but it does get better.”

– Patient diagnosed with atypical-HUS

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What are the risks of atypical-HUS?

Atypical-HUS affects every person differently, but everyone is at risk of life-threatening symptoms and complications. You should talk to your doctor about your symptoms. As the disease continues to damage small blood vessels, vital organs can fail to work, either suddenly or over time.1-4

How is atypical-HUS diagnosed?

Although atypical-HUS is a genetic disease, testing for specific genes is not necessary in order for your doctor to diagnose and manage atypical-HUS.1 It is important to accurately diagnose atypical-HUS because it has signs and symptoms similar to those of other diseases, including confusion, diarrhea, nausea and vomiting, shortness of breath, fatigue, heart symptoms, and kidney symptoms.1,11,12

Creatinine levelsCreatinine is a chemical waste molecule that is generated through muscle metabolism and is transported through the bloodstream to the kidneys. Creatinine has been found to be a fairly reliable indicator of kidney function; an elevated creatinine level in the blood can signify impaired kidney function or kidney disease.12, which can help your doctor understand how well your kidneys are working, is a typical test your doctor may perform. Your doctor may also look at your red blood cellRed blood cells (or erythrocytes) are the most common type of blood cell. They contain hemoglobin and are the body’s principal means of delivering oxygen to body tissues via the circulatory system.13 and platelet counts to see if they are low, which could be another sign of atypical-HUS.1,12,13

Additionally, ADAMTS13 is a test that can help your doctor differentiate atypical-HUS from other diseases. For instance, if a patient has less than 5% of normal ADAMTS13 levels, then TTP (thrombotic thrombocytopenic purpura) is the likely disease.1,10

Lastly, a doctor can check a patient’s stool sample to see if STEC-HUS (Shiga toxin-producing E. coli hemolytic uremic syndrome) – caused by an E coli infection – may be the cause of that patient’s symptoms.1 Talk with your doctor about any symptoms you may be experiencing, especially those that are recurring.

Be sure your doctor is aware of all your medical conditions. Commonly, people with atypical-HUS may have a triggering condition or a condition due to another distinct underlying cause. Diagnosis of a coexisting disease or condition should not rule out a diagnosis of atypical-HUS.1,2,10

It is important that you engage in discussions with your doctor about your symptoms. An ongoing dialogue with your doctor will help you learn more about your disease.

Connect with your support system

People living with atypical-HUS and their loved ones all have unique, special journeys supported by others. Find an upcoming event in your area to meet other people who understand what you’re going through and want to share their journey.

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