Diagnosis and Management of Mixed Phenotype Hereditary Transthyretin Amyloidosis: A Case-Based, Canadian Perspective

Hereditary amyloid transthyretin variant (ATTRv) amyloidosis is a rare, life-threatening disease, characterized by the deposition of aggregated transthyretin (TTR) protein in multiple organs and tissues. Diagnosis is often delayed due to its heterogeneity in presentation, which includes a wide range of cardiac and/or neurologic symptoms. Thus, awareness of ATTRv amyloidosis across multiple specialties is needed for its early diagnosis and management. This paper provides a review surrounding the diagnosis and management of mixed phenotype ATTRv amyloidosis, addressed through 3 clinical questions. This paper discusses: (i) the need for patients with ATTRv amyloidosis to be screened for mixed cardiac and neurologic phenotypes through early multidisciplinary referral; (ii) the therapeutic landscape for ATTRv amyloidosis in Canada, with emphasis on the need for prompt therapy selection and initiation, based on multidisciplinary collaboration; and (iii) how disease can be monitored pre- and post-treatment. Case studies are provided to illustrate how the available evidence impacts practice.