A team from the Oslo University Hospital, Norway, reported the first case in the country of hereditary transthyretin amyloidosis (hATTR) associated with the E54A (p.E74A) variant of the TTR gene.
At clinical presentation, the patient, a previously healthy 64-year-old man, complained of a 3-week history of New York Heart Association (NYHA) stage 2 dyspnea and a 6-month history of peripheral polyneuropathy symptoms with a diagnosis of a moderate degree of demyelinating peripheral polyneuropathy. He had had a previous surgery to treat bilateral carpal tunnel syndrome and reported a 10-kg weight loss and mild peripheral edema.
Physical examination revealed irregular heart rate at 45-75 bpm, with no distention of neck veins or heart murmur. His blood pressure was 140/78 mmHg. Moreover, he had alternate atrioventricular block, atrial flutter, and left bundle branch block, biventricular wall thickening, diastolic dysfunction, bi-atrial enlargement, and reduced contractility with an estimated ejection fraction of 42%. N-terminal pro-brain natriuretic peptide and troponin T levels were elevated.
“Biventricular hypertrophy without an obvious cause, elevated cardiac biomarkers, symptomatic peripheral polyneuropathy and a history of bilateral carpal tunnel syndrome are typically ‘red flags’ and raised suspicion of cardiac amyloidosis,” the team explained.
Read about hATTR etiology
Imaging studies strongly suggested transthyretin amyloid deposition, which was confirmed by abdominal fat tissue biopsy. Furthermore, genetic analysis of the TTR gene revealed a heterozygous mutation E54A (p.E74A) in exon 3.
The patient initiated tafamidis, loop diuretics, and anticoagulation therapy. In addition, he was implanted with a biventricular cardiac resynchronization therapy with a defibrillator.
At his 6-month outpatient follow-up, the patient showed improvements in hemodynamics, with an estimated ejection fraction greater than 55%, and was able to resume physical activities (NYHA stage 1).
“When ATTR–CM [transthyretin amyloid cardiomyopathy] is recognized before advanced organ dysfunction develops, patient outcomes can be improved using novel pharmacologic treatments, highlighting a new era for cardiac amyloidosis,” the team concluded.
Lyng CS, Gude E, Hodt A, Knudsen EC. First Norwegian case of hereditary ATTR amyloidosis with a novel transthyretin variant. Scand Cardiovasc J. 2023;57(1):2174269. doi:10.1080/14017431.2023.2174269