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Cross-provider research synthesis

Atypical Hemolytic Uremic Syndrome

MONDO:0016244 Curated 2026-07-04T00:00:00Z 9 harmonized findings
falcon · 44 citations openscientist · 34 citations
Concordant asserts the finding Partial supports a weaker/qualified form Contradictory conflicts with it Silent does not address it

Harmonized findings

aHUS is a rare, life-threatening thrombotic microangiopathy (TMA) driven by uncontrolled activation of the alternative complement pathway, causing microvascular endothelial injury, thrombosis, and multi-organ damage.

UNANIMOUS INTEGRATED
pathophysiology
ProviderStanceScoreEvidence
falcon CONCORDANT 95% aHUS/complement-mediated TMA is a rare, severe thrombotic microangiopathy driven by dysregulated alternative complement pathway activation, typically presenting with microangiopathic hemolytic anemia (MAHA), thrombocytopenia, and organ injury.
Falcon defines aHUS as a complement-mediated TMA from dysregulated alternative-pathway activation with the MAHA/thrombocytopenia/organ-injury triad.
DOI:10.1182/hematology.2025000702
openscientist CONCORDANT 95% Atypical hemolytic uremic syndrome (aHUS) is a rare, life-threatening thrombotic microangiopathy (TMA) characterized by complement dysregulation, leading to microvascular thrombosis and multi-organ injury
OpenScientist gives the same complement-dysregulation TMA definition with microvascular thrombosis and multi-organ injury.
PMID:40217974

aHUS is a genetically heterogeneous complement disorder caused by loss-of-function variants in complement regulators (CFH, CFI, CD46/MCP, THBD) or gain-of-function variants in activators (C3, CFB), plus DGKE and CFHR rearrangements, with anti-factor H autoantibodies as an important acquired cause; CFH is the most common gene (~30%).

UNANIMOUS INTEGRATED
genetic_factorpathophysiology
ProviderStanceScoreEvidence
falcon CONCORDANT 90% Commonly implicated genes include CFH, CFI, CD46/MCP, C3, CFB, THBD, DGKE, and CFHR rearrangements/deletions; anti-CFH autoimmunity is an important acquired mechanism.
Falcon lists the same core complement genes plus CFHR rearrangements and the acquired anti-CFH autoantibody mechanism.
DOI:10.1182/hematology.2024000543
openscientist CONCORDANT 95% different groups have demonstrated genetic predisposition to atypical HUS (aHUS) involving five genes encoding for complement components which play a role in the activation or control of the alternative pathway: encoding factor H (CFH), accounting for 30% of aHUS; CD46 (encoding membrane cofactor protein [MCP]) accounting for approximately 10% of aHUS; CFI (encoding factor I) accounting for an estimated 5-15% of patients; C3 (encoding C3) accounting for approximately 10% of aHUS; and rarely CFB (encoding factor B)
OpenScientist gives the same gene set with quantitative per-gene case frequencies (CFH 30%, CD46 10%, CFI 5-15%, C3 10%, CFB rare).
PMID:21376430

Complement variants confer predisposition with incomplete penetrance (~50%): most carriers require a second-hit environmental trigger (infection, pregnancy, surgery, malignancy, medications) to precipitate clinical disease.

UNANIMOUS INTEGRATED
genetic_factorpathophysiology
ProviderStanceScoreEvidence
falcon CONCORDANT 92% Penetrance is incomplete (~50% overall in one review), consistent with a multi-hit model requiring triggers such as infection, pregnancy, surgery, autoimmune disease, or transplantation.
Falcon states ~50% incomplete penetrance and the multi-hit trigger model explicitly.
DOI:10.1182/hematology.2024000543
openscientist CONCORDANT 90% Despite the presence of an underlying genetic etiology, an environmental trigger is often necessary to manifest disease, a phenomenon known as incomplete penetrance. These triggers could include infections, pregnancy, medication, cancers, or ischemia-reperfusion injury
OpenScientist describes the same incomplete-penetrance, trigger-dependent two-hit model with an overlapping trigger list.
PMID:40670222

Terminal complement C5 inhibitors (eculizumab, approved 2011; long-acting ravulizumab) have transformed aHUS outcomes, shifting the natural history from frequent progression to ESKD toward sustained hematologic and renal remission.

UNANIMOUS INTEGRATED
treatmentprognosis
ProviderStanceScoreEvidence
falcon CONCORDANT 90% In phase 3 trials, 2-year complete TMA response rates were 61% in C5 inhibitor-naive adults and 90% in pediatric patients.
Falcon documents durable 2-year efficacy of the C5 inhibitor ravulizumab in adults and children.
DOI:10.1016/j.xkme.2024.100855
openscientist CONCORDANT 95% Eculizumab, approved by the FDA in 2011, and its long-acting successor ravulizumab, have transformed outcomes from >50% progression to end-stage kidney disease (ESKD) to sustained hematological and renal remission in the majority of treated patients.
OpenScientist states the eculizumab/ravulizumab paradigm shift from >50% ESKD progression to remission.

aHUS is a diagnosis of exclusion requiring exclusion of TTP (severe ADAMTS13 deficiency <=10%) and Shiga toxin-producing E. coli HUS (Shiga toxin testing); a normal complement C3 does not exclude aHUS.

UNANIMOUS INTEGRATED
diagnosis
ProviderStanceScoreEvidence
falcon CONCORDANT 90% TTP should be rapidly excluded; severe ADAMTS13 deficiency (≤10%) supports TTP, while aHUS is more likely when ADAMTS13 is >10%.
Falcon frames aHUS as an exclusion diagnosis using ADAMTS13 to exclude TTP (and elsewhere Shiga toxin to exclude STEC-HUS; low C3 in <20%).
DOI:10.3390/jcm14072527
openscientist CONCORDANT 88% ADAMTS13 activity (>10% excludes TTP), anti-Factor H antibodies, Shiga toxin testing (excludes STEC-HUS)
OpenScientist lists the same exclusion workup: ADAMTS13 >10% excludes TTP and Shiga toxin testing excludes STEC-HUS.

aHUS is a rare disease (single-digit to ~10 cases per million prevalence) with a female predominance in adult-onset disease, attributed to pregnancy as a trigger.

MAJORITY INTEGRATED
epidemiology
ProviderStanceScoreEvidence
openscientist CONCORDANT 85% A total of 121 Belgian patients were registered in the Global aHUS Registry, resulting in a prevalence of 10.4 aHUS patients per million inhabitants, with a higher proportion of females affected (57.9% vs 42.1% of males)
OpenScientist cites a population prevalence of 10.4 per million with 57.9% female predominance.
PMID:41102576
falcon PARTIAL 55% Prevalence in individuals ≤20 years ranges from 2.2 to 9.4 per million; one all-ages prevalence estimate was 4.9 per million.
Falcon agrees aHUS is rare and that adults show higher female frequency, but cites a lower all-ages prevalence (4.9 per million) than OpenScientist's 10.4 per million — a quantitative discrepancy, not a contradiction.
DOI:10.2147/CLEP.S245642

Genotype predicts prognosis: CFH variants carry the highest risk of ESKD, relapse, and post-transplant recurrence, whereas CD46/MCP variants carry the most favorable outcome.

UNANIMOUS INTEGRATED
prognosisgenetic_factor
ProviderStanceScoreEvidence
falcon CONCORDANT 85% Estimated penetrance varies by gene: CFH ~50%; MCP/CD46 ~20%, with MCP often associated with better prognosis and lower post-transplant recurrence risk.
Falcon links MCP/CD46 to better prognosis and lower transplant recurrence, contrasting with the higher-penetrance CFH genotype.
DOI:10.3390/jcm14072527
openscientist CONCORDANT 90% with CFH mutations conferring the highest relapse risk and CD46/MCP mutations the most favorable prognosis
OpenScientist directly asserts CFH as highest relapse risk and CD46/MCP as most favorable prognosis.

Mouse models provide definitive in vivo proof that complement dysregulation causes aHUS and that C5 is essential — C5-deficient animals are protected — giving the mechanistic rationale for therapeutic C5 inhibition.

SINGLE INTEGRATED
pathophysiology
ProviderStanceScoreEvidence
openscientist CONCORDANT 90% spontaneous aHUS did not develop in any of the C5-deficient mice
OpenScientist reports the CFH-mutant/C5-deficient cross showing complete protection, proving C5-dependence and the rationale for eculizumab.
PMID:21148255
falcon SILENT —
Falcon's report explicitly states model-organism literature was not retrieved in this run ("Not available from retrieved sources in this run; no claims made"), so it does not cover the mouse-model evidence.

Proximal (upstream) complement inhibitors — Factor B inhibitors (iptacopan), Factor D inhibitors, and anti-properdin — are emerging beyond terminal C5 blockade and are retained as investigational leads.

MAJORITY LEAD
treatment
ProviderStanceScoreEvidence
openscientist CONCORDANT 85% (oral Factor B inhibitor): First successful use in SLE-aHUS
OpenScientist details emerging proximal inhibitors (iptacopan Factor B, Factor D inhibitors, anti-properdin) as therapies upstream of C5.
PMID:40996634
falcon PARTIAL 40% C5 is a validated therapeutic target; FDA/clinical development evidence includes eculizumab and ravulizumab, with additional phase 3 development for crovalimab.
Falcon notes only the next-generation C5 inhibitor crovalimab in development, not the proximal Factor B/D/properdin inhibitor class that OpenScientist emphasizes.

Narrative

Overview

Both providers frame atypical hemolytic uremic syndrome (aHUS) as a rare, complement-mediated thrombotic microangiopathy driven by uncontrolled activation of the alternative complement pathway, presenting as the TMA triad of microangiopathic hemolytic anemia, thrombocytopenia, and (predominantly renal) organ injury. Both center the disease on genetic/acquired defects in complement regulation, an incomplete-penetrance two-hit model, and the transformative role of terminal C5 inhibition.

Agreement

The reports concur on the core driver biology (alternative-pathway dysregulation causing endothelial injury and microvascular thrombosis); the genetic architecture (CFH ~30% as the leading gene, plus CD46/MCP, CFI, C3, CFB, THBD, DGKE and CFHR rearrangements, with anti-factor H autoantibodies as an acquired mechanism); incomplete penetrance (~50%) requiring a second-hit trigger; aHUS as a diagnosis of exclusion (ADAMTS13 >10% excludes TTP, Shiga toxin testing excludes STEC-HUS); the paradigm shift from C5 inhibitors (eculizumab/ravulizumab); and genotype-driven prognosis with CFH worst and CD46/MCP most favorable.

Divergence

OpenScientist is more quantitative and mechanistically deeper: it supplies definitive mouse-model evidence (CFH-mutant and C5-deficient crosses proving C5-dependence) that Falcon explicitly omits ("not available in this run"), emphasizes emerging proximal complement inhibitors (Factor B/iptacopan, Factor D, anti-properdin), and cites a population prevalence of 10.4 per million. Falcon reports a lower all-ages prevalence estimate (4.9 per million; 2.2-9.4 per million in those <=20 years), leans on pregnancy-associated aHUS meta-analysis outcomes and detailed extrarenal organ frequencies, and lists only crovalimab among newer agents. The two also disagree on the disease's MONDO identifier (Falcon: MONDO:0016244, matching the dismech entry; OpenScientist: MONDO:0019632) — an identifier discrepancy, not a biological contradiction. Extrarenal involvement is affirmed by both but with divergent organ-specific frequencies (e.g., Falcon neurologic 8-48%/27.2%, cardiac up to 43% in children; OpenScientist neurologic ~18%, cardiac ~19%, GI ~26%).

Integration

Integrated concepts for the disorder YAML: the alternative-pathway complement-dysregulation mechanism and TMA triad; the multi-gene genetic architecture with per-gene case fractions and the acquired anti-FH mechanism; incomplete penetrance and the two-hit trigger model; C5-inhibitor treatment with its outcome transformation; the exclusion-diagnosis workup; rare-disease epidemiology with adult female predominance; genotype-prognosis correlation; and the mouse-model proof of C5-dependence as mechanistic evidence.

Not integrated (leads)

Retained as research leads rather than promoted: emerging proximal complement inhibitors (Factor B/D and anti-properdin), single-provider quantitative figures with wide inter-report spread (organ-specific extrarenal frequencies, competing prevalence estimates), and the pregnancy-associated aHUS meta-analytic outcome statistics.

Cross-provider synthesis comparing the falcon (Edison Scientific Literature) and openscientist reports for atypical hemolytic uremic syndrome. No direct biological contradictions were found; divergence is coverage/quantitative (mouse-model evidence and proximal-inhibitor detail present only in OpenScientist; prevalence figures and extrarenal organ frequencies differ) plus a MONDO-identifier discrepancy. best_matching_text values are verbatim excerpts from the cited report files; literature evidence snippets and ontology terms are intentionally left to the main curation pipeline on the disorder YAML.