LAUSR

BACKGROUND Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a rare disorder caused by mutation of the forkhead box protein 3 (FOXP3) gene, often leading to intractable and life-threatening diarrhea. Fecal microbiota transplantation (FMT), has been regarded in recent years as an available approach to reconstruct disrupted gut microbiome and successfully used to attenuates diarrhea induced by different underlying diseases. Therefore, FMT may have curative potential on the symptoms of enteropathy in patients with IPEX syndrome. METHODS Physical and laboratory examinations were performed, and clinical data were collected. FMT was administered via frozen fecal microbial solution, and the fecal microbiota composition was analyzed using 16S rDNA sequencing before and after FMT. RESULTS The patient was diagnosed with IPEX syndrome with a mutation detected in the FOXP3 gene, which was identified as c.767T > C (p.M256T). He presented with recurrent watery diarrhea and respiratory infections after birth and developed a significant failure to thrive. Disturbances in the gut microbiota composition and marked decreased bacterial diversity were observed to be involved in the persistent and refractory diarrhea. After receiving FMT treatment, the patient responded with remission of the diarrhea without apparent side effects. His stool output significantly decreased, corresponding to increased microbial diversity and modification of his microbiota composition. The patient finally achieved full recovery after hematopoietic stem cell transplantation (HSCT). CONCLUSION Our data suggest an association between the gut microbiota and clinical symptoms of patient with IPEX syndrome and demonstrate FMT as an alternative therapy for severe diarrhea unresponsive to routine therapy in these patients.