Altered cortisol metabolism in individuals with HNF1A-MODY.

Objective and contextMaturity onset diabetes of the young due to variants in HNF1A (HNF1A-MODY) is the most common form of monogenic diabetes. Individuals with HNF1A-MODY usually have a lean phenotype which contrasts with type 2 diabetes (T2DM). Data from hepatocytes derived from Hnf1a knock-out mice demonstrated dysregulation of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), which regulates glucocorticoid availability and action in target tissues, together with 11β-HSD2 and steroid A-ring reductases, 5α- and 5β-reductase. We proposed that altered glucocorticoid metabolism might underpin some of the phenotypic differences between patients with HNF1A-MODY and those with T2DM.DesignA retrospective matched cohort study.Patients and measurements24-hours urine steroid metabolome profiling was carried out by gas chromatography-mass spectrometry in 35 subjects with HNF1A-MODY, 35 individuals with T2DM and 35 healthy controls matched for age, sex and BMI. The steroid metabolites were expressed as μg/L in all groups and measured in mid-morning urine in diabetic subjects and 24-hour urine collection in healthy controls. Hence, only ratios were compared not the individual steroids. Established ratios of glucocorticoid metabolites were used to estimate 11β-HSD1/2 and 5α- and 5β-reductase activities.ResultsWhile 11β-HSD1 activity was similar in all groups, 11β-HSD2 activity was significantly lower in subjects with HNF1A-MODY and T2DM than in healthy controls. The ratio of 5β- to 5α-metabolites of cortisol was higher in subjects with HNF1A-MODY than in T2DM and healthy controls, probably due to increased activity of the 5β-reductase (AKR1D1) in HNF1A-MODY.ConclusionsThis is the first report of steroid metabolites in HNF1A-MODY. We have identified distinct differences in steroid metabolism pathways in subjects with HNF1A-MODY that have the potential to alter steroid hormone availability. Further studies are required to explore whether these changes link to phenotype.