About Atypical Hemolytic Uremic Syndrome
Atypical HUS results from dysregulation of the alternative complement pathway, often triggered by genetic mutations in complement pathway genes (CFH, MCP, CFI, C3, CFB, THBD) or autoantibodies against Factor H. Environmental triggers may include infections, medications, pregnancy, or malignancy. Unlike Shiga toxin-producing E. coli HUS, aHUS is not preceded by diarrheal illness. The uncontrolled complement activation generates C5a and C5b-9, causing endothelial damage in the kidney microvasculature, platelet consumption, and mechanical destruction of red blood cells (hemolytic anemia). This thrombotic microangiopathy characteristically affects the renal microcirculation, leading to progressive kidney injury.
aHUS presents with the classic triad of microangiopathic hemolytic anemia, thrombocytopenia, and acute kidney injury, often progressing rapidly to end-stage renal disease if untreated. About 50% of untreated patients develop chronic kidney disease or end-stage renal disease. Extrarenal manifestations occur in 10-15% of patients, including thrombotic events, neurological complications, and cardiac involvement. Recurrence risk after kidney transplantation is high without complement-targeted prevention. Early recognition and prompt treatment with complement inhibitors such as eculizumab (C5 inhibitor) or other newer agents has dramatically improved outcomes.
Common Symptoms of Atypical Hemolytic Uremic Syndrome
Recognizing the signs of Atypical Hemolytic Uremic Syndrome early can lead to faster diagnosis and better outcomes. Symptoms may vary in severity from person to person. If you or a loved one are experiencing any of the following, consider speaking with a specialist.
- Microangiopathic hemolytic anemia with fatigue and pallor
- Thrombocytopenia causing easy bruising and petechiae
- Acute kidney injury with elevated creatinine
- Hematuria and proteinuria
- High blood pressure
- Neurological symptoms including confusion or seizures in severe cases
Who Atypical Hemolytic Uremic Syndrome Affects
Can occur at any age from infants to elderly, though commonly presents in young children and adolescents. Affects males and females equally. Can be sporadic or familial with autosomal dominant inheritance pattern. Genetic mutations in complement genes affect people of all ethnicities but may vary by population.
Find Your Next Step
Answer a few questions and we'll point you to the right tools and information for where you are right now.
Help Paying for Atypical Hemolytic Uremic Syndrome Treatment
Charity funds and drugmaker programs for Atypical Hemolytic Uremic Syndrome, checked at the source. Pick your insurance to see what fits.
- From a charity · NORD RareCareaHUS Medical Assistance fundOpen
Pays for: Medical and medication costs.
The foundation says: “Accepting new applications and re-enrollments for current year” - From a charity · NORD RareCareaHUS Premium Copay Assistance fundOpen
Pays for: Insurance premiums and copays.
The foundation says: “Accepting new applications and re-enrollments for current year” - From a charity · The Assistance FundAtypical Hemolytic Uremic Syndrome (aHUS) fundOpen
Pays for: Copays, coinsurance, deductibles and other health-related expenses.
The foundation says: “OPEN — Accepting New Patients. TAF is currently accepting new patient enrollments for this program.” - From a charity · TotalAssist (formerly PAN Foundation)Hemolytic Uremic Syndrome (HUS) fundOpen
Pays for: Out-of-pocket costs for approved medications, up to $9,500 per year. Requires health insurance (any kind).
Side Effect Explorer
Real-world side effect reports from the FDA Adverse Event Reporting System (FAERS). Includes both FDA-approved drugs and investigational therapies from active clinical trials. Click any drug to see what patients reported.
Loading side effect data...
Genetic Testing
Genetic testing can confirm a diagnosis, guide treatment decisions, and identify family members who may be at risk.
Finding labs...
Trusted Atypical Hemolytic Uremic Syndrome Resources
Reputable organizations and medical references for learning more about Atypical Hemolytic Uremic Syndrome, including disease registries, foundation resources, and clinical guidelines.