1552-P: Mutations with Residual CFTR Function Are Associated to Better Glucose Tolerance and Insulin Secretion in Patients with Cystic Fibrosis

People with Cystic Fibrosis (pwCF) exhibit a defect of insulin secretion[1], potentially leading to Cystic Fibrosis Related Diabetes. Little information exists about the molecular mechanism that links the defect of insulin secretion to the CF-causing variants of the CFTR gene[2,3]. We sought to describe the relationship between the CFTR function and β-cell function in pwCF. We studied 341 patients (193 (57%) females, 271 (79%) pancreatic insufficient, median (IQR) age 19 (15, 24) years) with the oral glucose tolerance test (OGTT), sampling glucose, insulin, and C-peptide before and every 30 minutes over the 2 hour OGTT, modeling β-cell function expressed by the β-cell glucose sensitivity[4]. Each patient was characterized by either having at least one allele with a residual function mutation (group 1, 85 (25%)), or a minimal function mutation on both alleles (group 2, 255 (75%) ). After adjusting for sex, pancreatic insufficiency (PI), and age, patients in group 1 displayed better glucose tolerance at all OGTT timepoint (all p=