**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.**
Joanna C. Dalland, Mayo Clinic, Rochester, MN

**Main Body of the Abstract**
Background: Patients with two different amyloid types have rarely been previously described. It is critical to identify all types of amyloid in a patient as amyloid therapies vary dramatically depending on the specific precursor protein.
Design: We queried our reference laboratory database of amyloid specimens from all anatomic sites typed by mass spectrometry-based proteomics (LC-MS/MS) for patients with diagnoses of two different types of amyloid. Demographic data including patient age, sex, and anatomic site of involvement was collected. The mass spectrometry proteomic features were reviewed.
Results: We identified 65 patients with two amyloid types (48 male (74%), 17 female (26%)). The average age at initial diagnosis was 74 years (range 26 to 91 years). 27 patients (42%) had cardiac involvement. The two types of amyloid were present either in two different anatomic locations (17 patients, 26%), in different anatomic compartments within a single specimen (33 patients, 51%), or in the same anatomic compartment within a single specimen (15 patients, 23%). Table 1 shows the various combinations we identified. The most common combination was AL plus ATTR (38 patients, 58%), which occurred in 19 patients with cardiac involvement.
Conclusion: The findings highlight the importance of determining the amyloid type in all cases, including careful review of the biopsy material to evaluate for distinct areas with different distribution, and considering the possibility of a second amyloid type when the clinical findings are not explained by the initial amyloid type. In some patients, this may require biopsy from a second anatomic site.



Dual Amyloidosis:  A Clinicopathologic and Proteomic Analysis of 65 Patients PA94 (#154)

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.