Highly Prevalent but Mild Neuropathic Burden in Wild-type Transthyretin Amyloidosis
Naman Bareja1, Maria Bartkus2, Ayan Patel3, Raymond Comenzo3, Oscar Soto3, Ron Riesenburger3
1Washington University School of Medicine, 2Lahey, 3Tufts Medical Center
Objective:
To assess the neuropathic burden and quality-of-life impact in patients with wild-type transthyretin amyloidosis (wtATTR) using standardized clinical and patient-reported outcomes.
Background:
Wild-type transthyretin amyloidosis is increasingly diagnosed in older adults and is associated with systemic involvement, especially cardiomyopathy. However, the burden and phenotype of neuropathy in wtATTR remain poorly defined due to limited prospective data.
Design/Methods:
For this prospective study, we screened 119 patients with confirmed transthyretin amyloidosis based on biopsy or technetium-PYP scanning and negative TTR genetic testing. Individuals with alternative causes of neuropathy were excluded. Of the 33 eligible individuals contacted, 10 completed full neurologic evaluation and patient-reported assessments. Neuropathic symptoms were measured using the Neuropathy Symptom Change (NSC) score. Neuropathy severity was quantified with the modified Neuropathy Impairment Score +7 (mNIS+7), EQ-5D, Norfolk-DN ADL, RODS, SFN RODS and RB SFN-SIQ.
Results:
Ten participants (7 male, 3 female; mean age 75) completed the study. All had systemic amyloidosis, with cardiac involvement (7/9 heart failure, 5/9 arrhythmia) and musculoskeletal (8/9 carpal tunnel syndrome, 3/9 biceps tendon rupture, 5/9 spinal stenosis). 7/10 patients had symptoms of neuropathy, with 3/7 with sensory neuropathy, 2/7 with sensorimotor neuropathy, and 4/7 with autonomic neuropathy. The mean mNIS+7 score was 13.9 (range 3–29), reflecting a mild neuropathic involvement. Mean score of PROs are (mean/max score): EQ-5D (68.56/100), Norfolk-DN ADL (1.56/116), RODS 44.44/48, SFN RODS 54.78/64, and SFN-SIQ 7.22/13.
Conclusions:
In contrast to the majority of hATTR mutations, this series shows a limited severity of neuropathic burden in wtATTR when comorbidities associated with neuropathy are excluded. 70% of patients with wild type TTR amyloidosis have a mild sensory and autonomic neuropathy, without severe Quality of life or functional impact. Disorders potentially causing neuropathy are highly prevalent in this population.
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