Transthyretin amyloidosis (ATTR amyloidosis) is characterized by the buildup of amyloid protein in organs like the gut and the heart. As a result, hypoperfusion, edema, and dysautonomia cause an imbalance in the gut microbiome. We aimed to identify the gut microbiome composition in ATTR amyloidosis patients with and without heart involvement, as well in controls. Sixty participants were divided into three groups: 20 with ATTR amyloidosis and heart involvement (G1), 19 with ATTR amyloidosis but no heart disease (G2), and 21 controls (G3). The microbiome profiles were obtained through 16S rRNA gene sequencing. Additional evaluations included a clinical questionnaire, echocardiogram, six-minute walk tests, troponin, BNP, and genotype analysis. Compared to G3, G1, and G2 groups had different levels of Streptococcus, Lachnospiraceae, and Sellimonas, while the controls showed a higher relative abundance of Methanosphaera. Streptococcus was linked to higher troponin levels. Lachnospiraceae was associated with lower BNP levels and smaller left atrium volumes. Sellimonas was associated with a higher intestinal symptom score, while Methanosphaera with a lower symptom score. ATTR amyloidosis patients have a different intestinal microbiome profile compared to the control group. There were correlations with genotype, gastrointestinal symptoms, heart failure biomarkers, echocardiographic parameters, and the six-minute walk test.

Systemic amyloidosis is a group of diseases caused by the deposition of an amyloid protein that forms fibrils and deposits in tissues. With respect to age and phenotype, patients with the Val122Ile transthyretin (TTR) mutation are similar to those with wild-type cardiac amyloidosis, causing a late-onset restrictive cardiomyopathy with minimal neuropathy, whose median age of onset is 69 years. Homozygous mutation is rare. We report the case of a male patient who had recent-onset heart failure and phenotype of [...] Abstract Systemic amyloidosis is a group of diseases caused by the deposition of an amyloid protein that forms fibrils and deposits in tissues. With respect to age and phenotype, patients with the Val122Ile transthyretin (TTR) mutation are similar to those with wild-type cardiac amyloidosis, causing a late-onset restrictive cardiomyopathy with minimal neuropathy, whose median age of onset is 69 years. Homozygous mutation is rare. We report the case of a male patient who had recent-onset heart failure and phenotype of