Monogenic diabetes is a group of disorders caused by mutations in any of one of a number of genes essential for the appropriate function of the insulin producing beta-cells in the pancreas. Estimates suggest that monogenic forms of diabetes could represent as much as 2% of all diabetes cases. Patients with diabetes occurring at an extremely young age, """"""""neonatal diabetes"""""""", are very likely to have an underlying monogenic cause, especially when diagnosed before 6 months of age. The University of Chicago Neonatal Diabetes Registry now includes clinical and genetic information on over 200 subjects with diabetes diagnosed prior to one year of age. The most common genetic cause of diabetes in this group are activating mutations in the gene KCNJ11, encoding the Kir6.2 subunit of the ATP-sensitive potassium (KATP) channel, which plays a critical role in insulin secretion. This group of subjects represent an unparalleled opportunity to investigate a human model of disruption of specific beta cell proteins critical for normal secretion of insulin. Patients with KCNJ11-related neonatal diabetes who were previously treated with insulin exhibit clinically excellent glucose control with minimal hypoglycemia when treated with sulfonylureas (usually glyburide). The predominant stimuli for secretion of insulin in sulfonylurea-treated patients have been suggested to be related to incretins rather than the metabolism of glucose. However, many questions remain regarding the nature of beta-cell function in such patients, as well as its long-term response to treatment. In this application, we thus propose the following Aims: 1) To fully characterize the insulin response to glucose in KCNJ11 patients compared to controls;2) To characterize the specific contribution of GLP-1 signaling on insulin secretion in KCNJ11 diabetes;3) To evaluate effect of age at genetic diagnosis of KCNJ11 diabetes and the role of incretin therapy in comparison with other forms of neonatal diabetes. During inpatient studies on subjects 18 years of age or older, we will use oral glucose tolerance testing (OGTT) followed by matched intravenous isoglycemic glucose infusion (IGI) to compare sulfonylurea-treated KCNJ11 patients with matched controls, then repeat these studies during infusions of GLP-1 and Exendin (9-39), a specific GLP-1 receptor antagonist. These tests will provide quantitative measures of insulin secretion with direct estimates of the incretin effect and evaluation of key incretin pancreatic and gut hormones. We will also monitor glucose excursion profiles with continuous glucose monitoring in response to OGTT in patients of all ages with KCNJ11 mutations as well as other forms of neonatal diabetes. These studies will test the following hypotheses: 1) Insulin secretory response to both intravenous and oral glucose is impaired in patients with KCNJ11 diabetes, 2) Oral glucose-regulated insulin secretion in KCNJ11 diabetes depends largely on GLP-1 signaling in the presence of elevated glucose, and 3) Glycemic control is dependent on age at conversion from insulin to oral sulfonylureas, that is, later age of instituting SU therapy leads to suboptimal glycemic control, with higher sulfonylurea dose and poorer neurodevelopmental outcome, and ii) glycemic control can be improved by treatment with incretin-based therapies. We anticipate that these studies will provide insight into beta cell function only possible through investigation of these rare subjects with genetic alteration of beta cell function. Furthermore, such studies have not yet been published in subjects with neonatal diabetes. We anticipate that these studies will elucidate the role of incretins in regulating insuln secretion independent of the KATP channel. Given that most of the genes causing monogenic diabetes have been associated with Type 2 diabetes through GWAS, better understanding of the pathophysiology of genetic defects causing human beta-cell dysfunction and how patients with mutations in these genes respond to different therapies could lead to improved diagnosis and treatment for those with more common polygenic forms of diabetes.

Public Health Relevance

The proposed studies will result in a deeper understanding of patients with human neonatal monogenic diabetes, likely to have direct future effects on the most appropriate long-term treatment for all forms of monogenic diabetes. In addition, the resulting insight into mechanisms of insulin secretion and its disruption may have ramifications for the millions of patients in the US with diabetes mellitus. Finally, the proposed studies represent a model for personalized genetic medicine, whereby iterative improvement in understanding of genotype/phenotype associations may have a dramatic impact on the treatment of individual patients, policies for genetic testing of others with similar phenotypes, and improvement of long term health outcome in these patients and those with related disorders.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Mentored Patient-Oriented Research Career Development Award (K23)
Project #
5K23DK094866-02
Application #
8461681
Study Section
Diabetes, Endocrinology and Metabolic Diseases B Subcommittee (DDK)
Program Officer
Hyde, James F
Project Start
2012-05-01
Project End
2015-03-31
Budget Start
2013-04-01
Budget End
2014-03-31
Support Year
2
Fiscal Year
2013
Total Cost
$173,242
Indirect Cost
$12,092
Name
University of Chicago
Department
Pediatrics
Type
Schools of Medicine
DUNS #
005421136
City
Chicago
State
IL
Country
United States
Zip Code
60637
Lanning, Monica S; Carmody, David; Szczerbi?ski, ?ukasz et al. (2018) Hypoglycemia in sulfonylurea-treated KCNJ11-neonatal diabetes: Mild-moderate symptomatic episodes occur infrequently but none involving unconsciousness or seizures. Pediatr Diabetes 19:393-397
Greeley, Siri Atma W; Letourneau, Lisa R; Philipson, Louis H (2018) Precision medicine in KCNJ11 permanent neonatal diabetes. Lancet Diabetes Endocrinol 6:594-595
Harris, Anastasia G; Letourneau, Lisa R; Greeley, Siri Atma W (2018) Monogenic diabetes: the impact of making the right diagnosis. Curr Opin Pediatr 30:558-567
Lemelman, Michelle Blanco; Letourneau, Lisa; Greeley, Siri Atma W (2018) Neonatal Diabetes Mellitus: An Update on Diagnosis and Management. Clin Perinatol 45:41-59
Roth, Theodore L; Puig-Saus, Cristina; Yu, Ruby et al. (2018) Reprogramming human T cell function and specificity with non-viral genome targeting. Nature 559:405-409
Sanyoura, May; Jacobsen, Laura; Carmody, David et al. (2018) Pancreatic Histopathology of Human Monogenic Diabetes Due to Causal Variants in KCNJ11, HNF1A, GATA6, and LMNA. J Clin Endocrinol Metab 103:35-45
Letourneau, Lisa R; Greeley, Siri Atma W (2018) Congenital Diabetes: Comprehensive Genetic Testing Allows for Improved Diagnosis and Treatment of Diabetes and Other Associated Features. Curr Diab Rep 18:46
Letourneau, Lisa R; Greeley, Siri Atma W (2018) Congenital forms of diabetes: the beta-cell and beyond. Curr Opin Genet Dev 50:25-34
Hwang, Jessica L; Park, Soo-Young; Ye, Honggang et al. (2018) FOXP3 mutations causing early-onset insulin-requiring diabetes but without other features of immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome. Pediatr Diabetes 19:388-392
Letourneau, Lisa R; Carmody, David; Philipson, Louis H et al. (2018) Early Intensive Insulin Use May Preserve ?-Cell Function in Neonatal Diabetes Due to Mutations in the Proinsulin Gene. J Endocr Soc 2:1-8

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