ATTR amyloidosis is two diseases, cardiomyopathy and polyneuropathy, and most of its estimated 100,000–150,000 US cardiomyopathy patients remain undiagnosed.
Transthyretin (TTR) amyloidosis arises when TTR tetramers dissociate and misfold into amyloid fibrils that deposit in tissue. It presents as two distinct diseases. ATTR cardiomyopathy (ATTR-CM), driven by amyloid deposition in the myocardium, is the larger commercial market; ATTR polyneuropathy (ATTR-PN), driven by peripheral-nerve deposition, is the historically nerve-led population. ATTR-CM is further split by genotype: wild-type disease (ATTRwt, age-related, roughly 80% of ATTR-CM) predominates in men over 70, while hereditary disease (ATTRv, roughly 20%) is driven by a pathogenic TTR variant — of which V122I (Val122Ile) is the most common in the US and disproportionately affects people of West African ancestry. Estimates place the US ATTR-CM population at roughly 100,000–150,000, but the majority remain undiagnosed.
The defining feature of the landscape is diagnostic, not therapeutic. Technetium-pyrophosphate (Tc-PYP) scintigraphy, validated by Gillmore and colleagues, now allows a non-biopsy diagnosis of ATTR-CM (Gillmore grade 2–3 with a monoclonal protein excluded) — replacing endomyocardial biopsy as the diagnostic gate. Echocardiographic clues (increased wall thickness, granular sparkling, apical-sparing longitudinal strain) are the front-door screen, and ATTR-CM is increasingly recognised as an under-diagnosed cause of heart failure with preserved ejection fraction and of severe aortic stenosis. Because tafamidis reduced all-cause mortality by 29.5% at 30 months in ATTR-ACT and two oral stabilizers plus three RNA silencers are now approved, the rate-limiting step for the market is finding patients, not treating them.
ATTR amyloidosis spectrum — phenotype, genotype, and treatment implication
| Subtype | Share (US est.) | Defining Feature | Key Clinical Burden | Treatment Implication |
|---|---|---|---|---|
| ATTRwt-CM (wild-type, age-related) | ~80% of ATTR-CM | Age-related TTR misfolding; men >70; no pathogenic variant | HFpEF, association with severe aortic stenosis, carpal tunnel, spinal stenosis | Tc-PYP scintigraphy diagnosis; oral TTR stabilizer (tafamidis / acoramidis) |
| ATTRv-CM (hereditary) | ~20% of ATTR-CM | Pathogenic TTR variant — V122I most common in the US | Earlier onset; often mixed cardiac and neuropathic disease | TTR genetic testing; stabilizer, with RNA silencers relevant where neuropathy present |
| ATTRv-PN (hereditary polyneuropathy) | Variant-driven (e.g. V30M) | Peripheral-nerve amyloid deposition | Progressive sensorimotor and autonomic neuropathy; disability | RNA silencer (patisiran / vutrisiran) or antisense (inotersen) |
| Undiagnosed ATTR-CM pool | Majority of estimated prevalent patients | Attributed to HFpEF, hypertensive, or age-related heart failure | Under-recognition; progression before diagnosis | Scintigraphy screening from echo red flags is the diagnostic-expansion lever |
Sources: Gillmore JD et al. Circulation 2016 (PMID 27143678); ATTR-ACT, NEJM 2018 (PMID 30145929); APOLLO, NEJM 2018 (PMID 29972753); HELIOS-A, Amyloid 2022 (PMID 35875890); FDA Drugs@FDA; ATTR epidemiology estimates (triangulated).
What this assessment answers
Every section answers a named commercial question your team is asking, scoped to your asset.
Delivers
- Diagnostic funnel from estimated to diagnosed prevalence
- scintigraphy referral and uptake
- HFpEF and aortic-stenosis screening yield
- the addressable diagnosed population
Delivers
- Phenotype and genotype segmentation
- TTR genetic testing
- the hereditary V122I cohort
- the mixed cardiac-plus-neuropathic phenotype
Delivers
- Treatment mapping by phenotype and indication
- oral stabilizers in ATTR-CM vs RNA silencers in ATTR-PN
- the implications of vutrisiran's cardiomyopathy filing
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Commission This AssessmentWhat's inside
- Why dissociating TTR tetramers that misfold into amyloid fibrils produce two distinct diseases: cardiomyopathy and polyneuropathy.
- How ATTR-CM's myocardial deposition and ATTR-PN's peripheral-nerve deposition split one misfolding protein into two markets.
- Why the estimated 100,000-to-150,000 US ATTR-CM population is roughly 80% wild-type disease in men over 70.
- How the majority of this 100,000-to-150,000 pool remains undiagnosed despite three approved TTR-targeted therapy classes.
- Why V122I, the most common US hereditary TTR variant, accounts for roughly 20% of ATTR-CM cases.
- How hereditary ATTRv-CM patients carrying V122I often present with earlier onset and mixed cardiac-neuropathic disease.
- Why Tc-PYP scintigraphy, validated by Gillmore et al., now enables non-biopsy diagnosis of ATTR-CM at grade 2-3.
- How echo red flags like apical-sparing strain and granular sparkling route HFpEF patients toward scintigraphy screening.
- Why tafamidis's 29.5% relative reduction in all-cause mortality at 30 months in ATTR-ACT redefined ATTR-CM treatment.
- How two oral stabilizers and three RNA silencers now approved make diagnosis, not treatment, the market's rate-limiting step.
- Why V122I, the most common US hereditary ATTR variant, disproportionately affects patients of West African ancestry.
- How this ancestry-linked variant concentration shapes which US patient subgroups warrant targeted TTR genetic testing.
Included with every brief
How AXLRx builds this assessment
Prepared by MoatRx analysts.
Every AXLRx assessment is built from primary regulatory sources (FDA Drugs@FDA, ClinicalTrials.gov), peer-reviewed literature, and live payer and HTA documentation — not secondary summaries, market-research reports, or unverified estimates. Findings are independently verified before inclusion; if a figure cannot be sourced to a live record, it does not ship.
US ATTR Amyloidosis Disease Landscape sources: FDA Drugs@FDA (approval status and indications), the non-biopsy diagnostic criteria of Gillmore JD et al. (Circulation 2016, PMID 27143678), and primary trial publications for the approved therapies — ATTR-ACT (NEJM 2018, PMID 30145929), APOLLO (NEJM 2018, PMID 29972753) and HELIOS-A (Amyloid 2022, PMID 35875890). Prevalence and the wild-type/hereditary split are presented as triangulated estimates.
- Non-biopsy Tc-PYP scintigraphy diagnostic pathway verified against Gillmore JD et al. Circulation 2016 (PMID 27143678)
- Tafamidis ATTR-CM mortality benefit verified against ATTR-ACT, NEJM 2018 (PMID 30145929)
- ATTR-PN RNA-silencer efficacy verified against APOLLO (PMID 29972753) and HELIOS-A (PMID 35875890)
- Approval status and indications verified against FDA Drugs@FDA
Frequently asked questions
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