**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.**
Chrysanthi Bountziouka
First Department of Neurology, School of Medicine, National and Kapodistrian University of Athens

**Main Body of the Abstract**
Background: Small Fiber Neuropathy (SFN) is a known complication of AL amyloidosis but has not been systematically evaluated. Aim: To investigate the prevalence and clinical significance of SFN in patients with AL amyloidosis.Methods: We prospectively evaluated 74 consecutive patients with newly diagnosed, previously untreated, AL amyloidosis (36 males, mean age 62.52 years, SD 9.86). The patients underwent neurological examination with Neurological Symptom Score, Neurologic Impairment Score, Quantitative Sensation Test (QST) and skin biopsy of the lower leg. Presence of Small fiber neuropathy (SFN) was defined as an abnormality of at least two clinical signs, intraepidermal nerve fiber density (IEFND) and QST results.  Results:  SFN was detected in 68.5% (n=50) of the patients;  in 18 (36%) was associated with pain and was asymptomatic in 10% (n=10). Follow-up and re-examination was performed 6-12 months following treatment initiation in 13 patients. All patients achieved bortezomib based regimens. No significant changes were observed in the clinical or electrophysiological findings at the timepoint of re-assessment. Reported symptoms did however deteriorate overall.  The median follow-up of the cohort was 28.17 months; 26 patients (35%) have died.  In univariate analysis, SFN was associated with shorter OS (p=0.024) and  early mortality <12 months (33% vs 4%, p=0.007), among patients with heart involvement (Mayo stage 2&3). Conclusion: Among AL patients the incidence of SFN is higher than previously estimated. Non-progression of neuropathy at reexaminations may indicate treatment response or disease stabilization. SFN seems to be an adverse prognostic factor and strong predictor of early mortality.



**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.**
Chrysanthi Bountziouka
First Department of Neurology, School of Medicine, National and Kapodistrian University of Athens

**Main Body of the Abstract**
**Background:** Small Fiber Neuropathy (SFN) is a known complication of AL amyloidosis but has not been systematically evaluated. **Aim**: To investigate the prevalence and clinical significance of SFN in patients with AL amyloidosis.**Methods**: We prospectively evaluated 74 consecutive patients with newly diagnosed, previously untreated, AL amyloidosis (36 males, mean age 62.52 years, SD 9.86). The patients underwent neurological examination with Neurological Symptom Score, Neurologic Impairment Score, Quantitative Sensation Test (QST) and skin biopsy of the lower leg. Presence of Small fiber neuropathy (SFN) was defined as an abnormality of at least two clinical signs, intraepidermal nerve fiber density (IEFND) and QST results.  **Results**:  SFN was detected in 68.5% (n=50) of the patients;  in 18 (36%) was associated with pain and was asymptomatic in 10% (n=10). Follow-up and re-examination was performed 6-12 months following treatment initiation in 13 patients. All patients achieved bortezomib based regimens. No significant changes were observed in the clinical or electrophysiological findings at the timepoint of re-assessment. Reported symptoms did however deteriorate overall.  The median follow-up of the cohort was 28.17 months; 26 patients (35%) have died.  In univariate analysis, SFN was associated with shorter OS (_p_=0.024) and  early mortality <12 months (33% vs 4%, p=0.007), among patients with heart involvement (Mayo stage 2&3). **Conclusion**: Among AL patients the incidence of SFN is higher than previously estimated. Non-progression of neuropathy at reexaminations may indicate treatment response or disease stabilization. SFN seems to be an adverse prognostic factor and strong predictor of early mortality.



Small Fiber Neuropathy in AL Amyloidosis: Clinical and Prognostic Implications PA60 (#206)

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.