Hereditary transthyretin amyloidosis (hATTR/ATTRv) + wtATTR

What changes during this transition

Transthyretin amyloidosis (ATTR) is a group of disorders defined by amyloid fibril deposition of misfolded transthyretin (TTR, prealbumin) — a tetrameric transport protein synthesized primarily by the liver (~99%) plus choroid plexus and retina, normally carrying thyroxine and retinol-binding protein/vitamin A. The disease has TWO MAIN FORMS. **Hereditary ATTR (hATTR / ATTRv = variant)** is autosomal dominant with over 130 identified TTR mutations and significant geographic clustering: V30M is endemic in Portuguese, Swedish, and Japanese populations (neuropathy-predominant phenotype, formerly called Familial Amyloid Polyneuropathy / FAP); V122I affects roughly 3–4% of African Americans (cardiac-predominant); T60A is the Irish/Appalachian variant (mixed phenotype); L111M is the Danish cardiac variant; many others exist across endemic foci globally. **Wild-type ATTR (wtATTR / ATTRwt)** involves non-mutated TTR that misfolds with age, predominantly affecting elderly males over 70, cardiac-predominant, formerly called 'senile systemic amyloidosis' and now recognized as a substantially underdiagnosed cause of HFpEF in elderly populations. Pathophysiologically, mutated or aged TTR tetramer dissociates into monomers, which misfold into oligomers and protofilaments, ultimately depositing as amyloid fibrils in target tissues. **Clinical phenotypes overlap considerably and are classified by predominance**: neuropathy-predominant ATTRv presents with progressive autonomic and length-dependent sensorimotor peripheral neuropathy (small and large fiber); cardiac-predominant ATTRv and wtATTR present as restrictive cardiomyopathy with heart failure, atrial fibrillation, AV block often requiring pacemaker, and transthyretin amyloid HFpEF; mixed phenotypes are common. Other manifestations include bilateral carpal tunnel syndrome (often decades before other symptoms — a critical red flag), lumbar spinal stenosis, biceps tendon rupture, vitreous opacity, glaucoma, renal involvement, and GI dysmotility. **The 'rule of 4s'** — bilateral carpal tunnel + lumbar spinal stenosis + biceps rupture + family history — exists because diagnostic delay is the norm; clinicians who pattern-match these red flags catch ATTR years earlier. **Diagnosis** combines clinical suspicion, TTR sequencing, and non-invasive cardiac imaging revolutionized by 99mTc-PYP/DPD/HMDP scintigraphy: intense myocardial uptake is diagnostic for cardiac ATTR without biopsy when monoclonal gammopathy is excluded by SPEP, UPEP, and serum free light chains (critical to rule out AL amyloidosis, which is monoclonal-protein-driven and has entirely different treatment and prognosis). Echo and cardiac MRI show specific patterns; tissue biopsy with Congo red staining and amyloid typing by mass spectrometry confirms when needed. Untreated, the disease is progressively disabling and fatal within 5–15 years of symptom onset depending on mutation, age, and phenotype. **Standard of care was transformed dramatically between 2018 and 2024 by peptide-class and small-molecule disease-modifying therapies**: **TAFAMIDIS (Vyndaqel/Vyndamax, Pfizer)** — TTR tetramer stabilizer binding the T4 binding sites to prevent dissociation — FDA-approved May 2019 for ATTR cardiomyopathy (both ATTRv and wtATTR) based on the ATTR-ACT trial showing mortality and hospitalization reduction; EMA approved earlier and Europe-approved for ATTRv neuropathy. **PATISIRAN (Onpattro, Alnylam)** — lipid nanoparticle-delivered siRNA reducing TTR protein synthesis by approximately 80% — FDA-approved August 2018 for hATTR neuropathy, IV every 3 weeks (first-in-class siRNA therapy, APOLLO trial). **INOTERSEN (Tegsedi, Akcea/Ionis)** — antisense oligonucleotide (ASO) — FDA-approved October 2018 for hATTR neuropathy, SC weekly, NEURO-TTR trial (thrombocytopenia and glomerulonephritis side effects limit use). **VUTRISIRAN (Amvuttra, Alnylam)** — GalNAc-conjugated siRNA — FDA-approved June 2022 for hATTR neuropathy, SC every 3 months, HELIOS-A trial; **expanded March 2025 to ATTR cardiomyopathy** based on HELIOS-B showing mortality and cardiovascular event reduction. **ACORAMIDIS (Attruby, BridgeBio)** — next-generation TTR stabilizer with near-complete tetramer stabilization, oral BID — FDA-approved November 2024 for ATTR cardiomyopathy based on ATTRibute-CM. **EPLONTERSEN (Wainua, Ionis/AstraZeneca)** — GalNAc-conjugated ASO with improved dosing over inotersen, SC monthly — FDA-approved December 2023 for hATTR neuropathy (NEURO-TTRansform); cardiomyopathy trial ongoing. **NTLA-2001 (Intellia)** — in vivo CRISPR-Cas9 gene editing permanently disabling the TTR gene with a single IV dose — Phase 3 MAGNITUDE trial with readouts emerging. Supportive care includes cardiac heart-failure management (challenging in restrictive physiology — diuretics carefully, cautious beta-blocker and ACEi use, anticoagulation for atrial fibrillation, pacemakers for conduction disease), historical liver transplantation for ATTRv neuropathy (now largely supplanted by silencer therapies), orthotics, physical and occupational therapy, pain management, and autonomic-symptom management. This disease has been transformed for community members from a death sentence to one with multiple peptide-class disease-modifying therapies, and the editorial framing of community peptides must reflect that. Multi-jurisdictional disease across Portuguese (Northern Portugal — Andrade's original 1952 description), Japanese, Swedish, African American, Irish/Appalachian, and Danish endemic foci among others; pregnancy in asymptomatic carriers and family cascade screening are significant clinical concerns; wtATTR diagnostic delay in elderly HFpEF populations remains substantial; access and cost of disease-modifying therapies are real barriers globally. Community peptide therapies (BPC-157, NMN, CJC-1295, tesamorelin, ipamorelin, semaglutide) have no role in ATTR — they sit alongside this catalog as substrate clarifying why disease-modifying therapy from the amyloidosis specialist is the load-bearing intervention. Advocacy: Amyloidosis Research Consortium, Amyloidosis Foundation, Amyloidosis Support Groups (US), Hereditary Amyloidosis Foundation, ATTR Amyloidosis Network UK, Mackay-Australian Amyloidosis Foundation, and the International Endpoints in TTR Network. Guidelines: ESC 2021 cardiac amyloidosis position paper, AHA 2020 scientific statement, European Amyloidosis Association expert consensus. Seventy-seventh deliberate non-elevation of community peptides.