Familial amyloid with a transthyretin leucine 33 mutation presenting with ascites

Unusual presentation of rare Phe33Leu mutation hereditary TTR cardiac amyloidosis

Introduction: Hereditary TTR cardiac amyloidosis (ATTRv-CM) is a progressive and rare autosomal dominant disease, causing the formation of insoluble amyloid fibrils that deposit in the heart and nervous tissue. Case description: The authors present a 64-year-old man who was found to have the Phe33Leu mutation causing ATTRv-CM without any neurological signs or symptoms. He presented with persistent atrial fibrillation that was refractory to anti-arrhythmic medications and multiple ablations. He was diagnosed with ATTRv-CM by a Tc-99m pyrophosphate cardiac amyloid scan. Intervention: He was treated with tafamidis, torsemide and spironolactone therapy. The patient suffered cardiac arrest and passed away. Conclusion: Clinicians should be aware of the atypical presentations of ATTRv-CM without neurological signs.

Hereditary transthyretin amyloidosis caused by the rare Phe33Leu mutation

Hereditary transthyretin amyloidosis is a rare progressive systemic disease. We describe a physically active 46-year-old man who presented with dyspnoea on exertion. An echocardiogram showed increased left ventricular wall thickness and diastolic dysfunction, but normal systolic function. The QRS voltage on ECG was normal. The patient was diagnosed with hypertrophic cardiomyopathy, and several years passed before establishment of the accurate diagnosis of hereditary transthyretin amyloidosis caused by the rare mutation ATTR Phe33Leu, previously described in only five case reports. Further investigation revealed neuropathy and nephropathy, and the patient developed severe heart failure. The patient is treated with tafamidis, has undergone heart transplantation and is currently planned for liver transplant. Hereditary transthyretin amyloidosis is likely underdiagnosed, especially in patients presenting with cardiomyopathy. A discrepancy between the left ventricular mass indicated by echocardiogram and that on ECG is an important indicator of amyloidosis, as is involvement of multiple organs.

A Swedish family with the rare Phe33Leu transthyretin mutation

Familial amyloidotic polyneuropathy (FAP) designates TTR mutations where the phenotype is dominated by a peripheral sensory-motor polyneuropathy. The most common mutation is ATTR Val30Met. FAP in association with ATTR Phe33Leu has been described previously in two American families, one of Polish-Lithuanian descent and the other of Polish-American. In this study, we report the phenotype of the ATTR Phe33Leu in a Swedish family. The proband is a 48 year-old patient from northern Sweden, whose father died with symptoms suggestive of FAP. Characteristic clinical features included polyneuropathy, carpal tunnel syndrome and asymptomatic, but echocardiographic examination diagnosed cardiomyopathy. The family history supports an early intervention with orthotopic liver transplantation in patients with FAP associated with the TTR Phe33Leu, and the patient was submitted for liver transplantation.