Transthyretin amyloid-related transitory events (TARTEs): Descriptive analysis of clinical, imagiological, and neurophysiological features.

Abstract Transthyretin-related familial amyloid polyneuropathy (ATTR-FAP) is a multisystemic disorder inherited as an autosomal dominant trait. Transitory events in ATTR-FAP patients are a feature of this disorder and remain poorly depicted in the literature. We aimed to describe a case series of ATTR-FAP patients who presented to our department with transitory events and document the clinical, neuroimaging and neurophysiological characteristics of the events. We collected data from eight patients carrying the Val30Met ATTR-FAP variant. We registered a total of 23 events. Of the eight patients, seven had been submitted to hepatic transplant. The events were either TIA-like or seizures, often followed by prolonged language, motor or sensory impairment. In 9 (39%) of the events, the patients presented with fever, but an infection was only found in 5 (21%). Cerebrospinal fluid analysis was performed in 5 patients. EEG was abnormal in at least 1 event in 7 of the 8 patients. Brain MRI was performed in 3 patients during the acute stage and showed no acute lesions. Although the etiology of these events remains unclear, brain MRI performed in the acute phase of acute TIA-like events and the EEG abnormalities, argues in favor of regional brain dysfunction due to amyloid deposition. Focal neurological episodes should be considered in long-term duration Val30Met ATTR-FAP patients, who present with acute neurological deficits or seizures.