Is there room at this stage for some compromise on a new name for aHUS?
Would something like cTMA-HUS or even cTMAHUS be a good new name?
Experts would probably say no it is not the best new name for aHUS. Why do experts want a change?
Experts widely agree that “atypical hemolytic uremic syndrome (aHUS)” is outdated and suboptimal:
- “Atypical” only means “not the diarrhea/STEC form.”
- It does not describe the underlying mechanism (uncontrolled alternative-pathway complement activation leading to endothelial injury and thrombotic microangiopathy).
- It creates confusion with other TMAs and secondary forms.
Major groups (including the 2024 National Kidney Foundation Working Group) recommend moving toward an etiology-based nomenclature centered on “complement-mediated thrombotic microangiopathy.”
Current preferred term and the most commonly proposed and increasingly used replacements are:
- Complement-mediated thrombotic microangiopathy (CM-TMA or C-TMA)
- Sometimes Complement-mediated HUS (CM-HUS)
These are then further subclassified, for example:
- Genetic C-TMA / GC-TMA
- Anti-CFH antibody–mediated TMA
- C-TMA with no identified pathogenic variant
Sometimes? And then there are three more names.
An Assessment of “cTMA-HUS or cTMAHUS includes possible advantages
- It tries to keep the familiar “HUS” label (helpful for clinicians and patients already used to aHUS).
- It signals both the thrombotic microangiopathy nature and the complement mediation.
Significant drawbacks
- It creates yet another hybrid abbreviation in an already crowded and inconsistent landscape (aHUS, CM-TMA, C-TMA, CM-HUS, CaHUS, CHUS etc, Its the wild west out there).
- Expert consensus is moving away from retaining “HUS” because it perpetuates the old typical/atypical distinction.
- Cleaner, purely mechanism-based terms (CM-TMA / C-TMA) are preferred for precision, research, and future classification.
- No major working group or consensus paper has proposed or endorsed “cTMA-HUS.” or “CTMAHUS”
Bottom line “cTMA-HUS” “cTMAHUS” is an understandable attempt at a compromise, but it is unlikely to become the standard. The direction of travel in the literature and expert groups is toward CM-TMA or C-TMA (with additional qualifiers when the genetic or autoantibody status is known). A clean break from the old aHUS terminology is generally viewed as more helpful in the long run than a hybrid name.
But what if cTMA- HUS or cTMAHUS stands for complement mediated thrombotic microangiopathy – hemolytic uremic spectrum
That would be a thoughtful refinement.
Proposed expansion cTMA-HUS, cTMAHUS = Complement-mediated Thrombotic Microangiopathy – Hemolytic Uremic Spectrum – the strengths of this idea
- It explicitly links the modern pathophysiological term (Complement-mediated Thrombotic Microangiopathy) with the traditional clinical phenotype (Hemolytic Uremic).
- The word “Spectrum” is useful. It acknowledges that these disorders exist on a continuum (from predominantly renal HUS-like presentations to more systemic TMA, with or without identifiable genetic/autoantibody drivers, and with varying triggers).
- It softens the hard break from the familiar “aHUS” label, which many clinicians, patients, and regulatory documents still use.
- It could serve as an umbrella term while still allowing more precise subtypes (e.g., genetic cTMA-HUS, anti-CFH cTMA-HUS, idiopathic cTMA-HUS).
There are weaknesses and practical concerns
- Length and complexity: “Complement-mediated Thrombotic Microangiopathy – Hemolytic Uremic Spectrum” is long. Even the acronym “cTMA-HUS” “cTMAHUS” is not immediately intuitive without explanation.
- Risk of further fragmentation: The field already struggles with multiple competing terms (aHUS, CM-TMA, C-TMA, CM-HUS, CaHUS). Adding another hybrid risks more confusion rather than resolution. Admittedly though it does not stop others at the moment
- Expert preference from recent high-level discussions (National Kidney Foundation Working Group 2024 and subsequent papers) lean toward clean, etiology-first terms such as CM-TMA or C-TMA, with optional qualifiers. They generally prefer to move away from retaining “HUS” in the core name.
- Spectrum concept is already partly captured: Many authors already describe aHUS/CM-TMA as a spectrum disorder. Explicitly putting “spectrum” into the official name may be redundant for experts while still feeling awkward for everyday clinical use.
Overall verdict might be that is one of the more thoughtful hybrid proposals seen.
It tries to bridge the old clinical language with the new mechanistic understanding and highlights the spectrum nature.
Overall although it is one of the more thoughtful hybrid proposals seen. It tries to bridge the old clinical language with the new mechanistic understanding and highlights the spectrum nature of the disease. However, it is still unlikely to become the consensus standard. The strongest momentum is currently behind simpler forms such as: Sometimes CM-HUS when authors want to keep a clearer link to the hemolytic-uremic phenotype.CM-TMA / C-TMA (Complement-mediated Thrombotic Microangiopathy)
All things considered there is really no room for compromise on what the experts want.
If you are for the change proposed by experts cast your vote HERE
What about Pharma and Patients ? ( Go to part 2)
Article No. 818
