Using Human Induced Pluripotent Stem Cell Derived Organoids to Identify New Pathologies in Patients with PDX1 Mutations

Two patients with homozygous mutations in PDX1 presented with pancreatic agenesis, chronic diarrhea and poor weight gain, the causes of which were not identified through routine clinical testing. We aim to perform a deep analysis of the stomach and intestine using organoids derived from induced pluripotent stem cells from PDX1188delC/188delC patients.Gastric fundic, antral and duodenal organoids were generated using iPSC lines from a PDX1188delC/188delC patient and an isogenic iPSC line where the PDX1 point mutation was corrected.Patient-derived PDX1188delC/188delC antral organoids exhibited an intestinal phenotype, while intestinal organoids underwent gastric metaplasia with significant reduction in enteroendocrine cells. This prompted a re-examination of gastric and intestinal biopsies from both PDX1188delC/188delC patients, which recapitulated the organoid phenotypes. Moreover, antral biopsies also demonstrated increased parietal cells and lacked G-cells suggesting loss of antral identity. All organoid pathologies were reversed upon CRISPR-mediated correction of the mutation.These patients will now be monitored for the progression of metaplasia and gastrointestinal complications that might be related to the reduced gastric and intestinal endocrine cells. This study demonstrates the utility of organoids in diagnosing uncovered pathologies.