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Genetic and Rare Diseases Information Center (GARD)

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Atypical hemolytic uremic syndrome

Other Names for this Disease
  • AHUS
  • Atypical HUS
  • HUS, atypical
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What is hemolytic-uremic syndrome, atypical?

Is genetic testing available for atypical hemolytic-uremic syndrome?

What is hemolytic-uremic syndrome, atypical?

Atypical hemolytic-uremic syndrome (aHUS) is a disease that causes abnormal blood clots to form in small blood vessels in the kidneys. These clots can cause serious medical problems if they restrict or block blood flow, including hemolytic anemia, thrombocytopenia, and kidney failure. It can occur at any age and is often caused by a combination of environmental and genetic factors. Genetic factors involve genes that code for proteins that help control the complement system (part of your body’s immune system). Environmental factors include certain medications (such as anticancer drugs), chronic diseases (e.g., systemic sclerosis and malignant hypertension), viral or bacterial infections, cancers, organ transplantation, and pregnancy.  Most cases are sporadic. Less than 20 percent of all cases have been reported to run in families. When the disorder is familial, it can have an autosomal dominant or an autosomal recessive pattern of inheritance.[1][2]

Atypical hemolytic-uremic syndrome differs from a more common condition called typical hemolytic-uremic syndrome. The two disorders have different causes and different signs and symptoms.[2]

Last updated: 9/27/2010

Is genetic testing available for atypical hemolytic-uremic syndrome?

GeneTests lists the names of laboratories that are performing genetic testing for atypical hemolytic-uremic syndrome. To view the contact information for the clinical laboratories conducting testing click here and follow the "testing" link pertaining to each gene.

Please note:  Most of the laboratories listed through GeneTests do not accept direct contact from patients and their families; therefore, if you are interested in learning more, you will need to work with a health care provider or a genetics professional.  In the Genetic Services section of this letter we provide a list of online resources that can assist you in locating a genetics professional near you.
Last updated: 3/26/2012

  1. Alpers CE. The Kidney. In: Kumar ed. Robbins and Cotran Pathologic Basis of Disease, Professional Edition , 8th ed. Philadelphia, PA: Saunders; 2009;
  2. Atypical hemolytic-uremic syndrome. Genetics Home Reference. 2010; Accessed 9/27/2010.