When and Where Does a Carrier of Hereditary Transthyretin Amyloidosis (Ile88leu) Show the First Signs of the Disease? Diagnostic Challenges of a Not Only Cardiogenic Mutation

Abstract We present the case of a 58–year–old man with a familiar history (mother affected) positive for ATTR–v (Ile88Leu) amyloidosis. The mother initially had a pure cardiac phenotype and was firstly treated with tafamidis, but progression of the disease to the nervous system warranted a switch to patisiran. Our patient carried the Ile88Leu mutation and had a medical history notable for surgically treated left carpal tunnel syndrome (CTS) and untreated right CTS. Furthermore, he was affected by systemic arterial hypertension and was a habitual smoker. He has been followed at our Institution since 2018. His first echocardiogram showed normal left ventricular ejection fraction (LVEF 65%), mild hypertrophy (anterior septum: 12 mm), and borderline values of GLS (– 16%) without any specific pattern. Further exams were executed: Bone scintigraphy (BS): negative (Perugini score 0); Coronary artery ct scan: moderate stenosis of proximal LAD; Neurologic evaluation: no signs of peripheral neuropathy. The clinical picture remained unaltered in 2020 and 2021. However, during November 2022 the patient developed atrial fibrillation (AF) and presented to the ED for dyspnea and palpitations. Electrical cardioversion was performed with success but subsequent recurrences warranted AF ablation in April 2023. At that moment, the patient was re–evaluated. Basal ECG did not show any significant alteration (FIg.1)This time, echocardiogram showed mild worsening of hypertrophy (13 mm septum), GLS – 16% with apical sparing pattern, no other major variations (Fig.2). BS was repeated and revealed grade 1 Perugini score (Fig.3). Hence, a series of clinical question arose: Should we begin a specific treatment or is the disease in an excessively early stage that does not warrant treatment? Is AF linked to concomitant arterial hypertension or might it be an early marker of disease? We questioned the usefulness of endomyocardial biopsy in this specific setting. In this case, we repeated electromyography that showed mild axonal sensitive–motor polyneuropathy. Finally, we concluded for initial signs of systemic amyloidosis ATTR–v (Ile88Leu) type with mixed phenotype (neurological+cardiac). The neurological involvement allowed us to start a gene–silencer (Patisiran). In conclusion, a periodic neurological evaluation is necessary and has crucial therapeutic implications in all genotypes. Indeed, there is increasing evidence that Ile88Leu is a not only cardiogenic mutation.