Alterations in gut microbiota composition in adult patients with familial Mediterranean fever: a pilot case-control study.

Abstract

Background/aim: Although familial Mediterranean fever (FMF) is a monogenic disease, recent evidence suggests that the gut microbiota may play a role in its pathogenesis or phenotypic expression. We conducted a pilot exploratory study to evaluate the intestinal microbiota composition in patients with FMF and compare it to that of healthy controls.

Materials and methods: In this prospective cohort study, 10 adult patients with FMF receiving colchicine and 10 age- and sex-matched healthy controls were enrolled. Fecal samples were collected and stored at -80 °C until DNA extraction. The V3-V4 region of the 16S rRNA gene was amplified and sequencing was performed.

Results: Alpha and beta diversity metrics were largely similar between FMF patients and the control group, except for the Chao 1 index, which was significantly reduced in the FMF group (p < 0.05), indicating lower species richness. Taxonomic analysis revealed differences in gut microbiota composition, notably an increased abundance of Eggerthella at the genus level. At the species level, Eggerthella sinensis and Eggerthella lenta were more prevalent in FMF patients.

Conclusion: Our findings reveal distinct gut microbiota alterations in FMF patients, characterized by reduced microbial richness and particularly enrichment of Eggerthella, including E. lenta. These findings suggest a possible association between gut microbiota alterations and FMF. The small sample size of this study is a limitation, but further longitudinal studies with treatment-naïve patients, alongside functional analyses of microbial metabolites, are warranted to elucidate causal relationships and inform microbiome-based diagnostic or therapeutic strategies in FMF.