Generation of ß Cells from iPSC of a MODY8 Patient with a Novel Mutation in the Carboxyl Ester Lipase (CEL) Gene.

CONTEXT: Maturity-onset diabetes of the young (MODY) 8 is a rare form of monogenic diabetes characterized by a mutation in CEL (carboxyl ester lipase) gene, which leads to exocrine pancreas dysfunction, followed by ß cell failure. Induced pluripotent stem cells can differentiate into functional ß cells. Thus, ß cells from MODY8 patients can be generated in vitro and used for disease modelling and cell replacement therapy. METHODS: A genetic study was performed in a patient suspected of monogenic diabetes. RESULTS: A novel heterozygous pathogenic variant in CEL (c.1818delC) was identified in the proband, allowing diagnosis of MODY8. Three MODY8-iPSC (induced pluripotent stem cell) clones were reprogrammed from skin fibroblasts of the patient, and their pluripotency and genomic stability confirmed. All 3 MODY8-iPSC differentiated into ß cells following developmental stages. MODY8-iPSC-derived ß cells were able to secrete insulin upon glucose dynamic perifusion. The CEL gene was not expressed in iPSCs nor during any steps of endocrine differentiation. CONCLUSION: iPSC lines from a MODY8 patient with a novel pathogenic variant in the CEL gene were generated; they are capable of differentiation into endocrine cells, and ß cell function is preserved in mutated cells. These results set the basis for in vitro modelling of the disease and potentially for autologous ß cell replacement.