**Author Listing - Lead/ Submitting Author (we will be communicating with this individual): Name, Institution, City and State where the work was done. Co-authors will be added in a separate section.**
Dr Vincent Algalarrondo
Cardiology department, CHU Bichat, Reference Center for Cardiac Amyloidosis (CERAMIC-CARDIO) and Université Paris-Cité, Paris, France.

**Main Body of the Abstract**
Introduction:
Hereditary transthyretin amyloidosis (ATTRv) arising from the TTR gene V30M variant (ATTRV30M) manifests in two distinct phenotypes: early-onset (before age 50 years) with polyneuropathy and late-onset (after age 50 years) with a mixed phenotype, encompassing neurological and cardiac manifestations (ATTR-CM). Comparative studies examining ATTR-CM in early and late ATTRV30M have typically involved patients post-diagnosis, with early-onset individuals being younger. This study aimed to compare ATTR-CM in early and late ATTRV30M at similar ages.
Methods:
Medical records of 370 ATTRV30M patients were analysed (median follow-up: 3.6 years), summarizing data by 10-year age groups. Confirmed ATTR-CM was defined by a DPD scan (Perugini score ≥2), positive amyloid biopsy (Perugini score grade 1), or typical echocardiographic appearance (unexplained interventricular septum ≥13 mm).
Results:
Among V30M carriers, 138 had early-onset polyneuropathy, 113 late-onset polyneuropathy, and 119 were asymptomatic carriers. ATTR-CM was confirmed in 16.7% of early-onset, 75.2% of late-onset, and 3.9% of asymptomatic carriers. ATTR-CM frequency increased with age. In a given age group, ATTR-CM degree was identical in early and late-onset groups (see Figure). Conversely, asymptomatic carriers showed lower ATTR-CM frequency (P=0.001 in the 50-59yo age group, p< 0.001 in the 60-69yo age group). Late-onset patients had significantly higher life expectancy than early-onset patients (median survival: 83yo and 62yo, respectively; P<0.001).
Conclusions:
In a comparable age group, ATTR-CM extent is consistent in early and late-onset ATTRV30M. ATTR-CM penetrance rises with age, and both early and late-onset ATTRV30M exhibit a mixed phenotype. Neurological manifestations precede ATTR-CM onset.



ATTR Cardiomyopathy in Early and Late onset ATTRV30M: Two Sides of the Same Coin? PB22 (#74)

We invite you to attend the XIX International Symposium on Amyloidosis to be held in Rochester, MN.

This symposium is organized as a hybrid meeting (with the focus on in-person) held from Sunday, May 26 through Thursday, May 30, 2024.

Together with the ISA Board and members of Mayo Clinic, a very attractive scientific hybrid program is being planned. The program will cover a variety of types of systemic amyloidosis: ATTR (hereditary and wild-type), AL (light-chain), AA and less frequent forms. There will be key lectures, specific symposia including those company sponsored, oral presentations and poster sessions of accepted abstracts.

COURSE DESCRIPTION
This program will provide a comprehensive review of state-of-the-art education in systemic amyloidosis: basic science, pathophysiology, diagnosis, current and emerging treatments. Scientific presentations will include competitive oral and poster abstracts. The rapid evolution of scientific discovery and expanding treatment options has created tremendous interest in the field and this meeting will fill and important gap in educating scientists and clinicians.