{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,12]],"date-time":"2026-09-12T09:04:23Z","timestamp":1789203863842,"version":"build-2803163510"},"reference-count":34,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2022,6,6]],"date-time":"2022-06-06T00:00:00Z","timestamp":1654473600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Endocrinol."],"abstract":"<jats:sec><jats:title>Background<\/jats:title><jats:p>The <jats:italic>MTNR1B<\/jats:italic> gene encodes a receptor for melatonin, a hormone regulating biorhythms. Disruptions in biorhythms contribute to the development of type 2 diabetes mellitus (T2DM). Genetic studies suggest that variability in the <jats:italic>MTNR1B<\/jats:italic> gene affects T2DM development. Our aim was to compare the distribution of the genetic variant rs10830963 between persons differing in glucose tolerance in a sample of the Czech population (N=1206). We also evaluated possible associations of the polymorphism with insulin sensitivity, beta cell function, with the shape of glucose, insulin and C-peptide trajectories measured 7 times during a 3-hour oral glucose tolerance test (OGTT) and with glucagon response. In a subgroup of 268 volunteers we also evaluated sleep patterns and biorhythm.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p>13 persons were diagnosed with T2DM, 119 had impaired fasting blood glucose (IFG) and\/or impaired glucose tolerance (IGT). 1074 participants showed normal results and formed a control group. A higher frequency of minor allele G was found in the IFG\/IGT group in comparison with controls. The GG constellation was present in 23% of diabetics, in 17% of IFG\/IGT probands and in 11% of controls. Compared to CC and CG genotypes, GG homozygotes showed higher stimulated glycemia levels during the OGTT. Homozygous as well as heterozygous carriers of the G allele showed lower very early phase of insulin and C-peptide secretion with unchanged insulin sensitivity. These differences remained significant after excluding diabetics and the IFG\/IGT group from the analysis. No associations of the genotype with the shape of OGTT-based trajectories, with glucagon or with chronobiological patterns were observed. However, the shape of the trajectories differed significantly between men and women.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>In a representative sample of the Czech population, the G allele of the rs10830963 polymorphism is associated with impaired early phase of beta cell function, and this is evident even in healthy individuals.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fendo.2022.868364","type":"journal-article","created":{"date-parts":[[2022,6,6]],"date-time":"2022-06-06T09:37:02Z","timestamp":1654508222000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":17,"title":["The rs10830963 Polymorphism of the MTNR1B Gene: Association With Abnormal Glucose, Insulin and C-peptide Kinetics"],"prefix":"10.3389","volume":"13","author":[{"given":"Daniela","family":"Vejrazkova","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marketa","family":"Vankova","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Josef","family":"Vcelak","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hana","family":"Krejci","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Katerina","family":"Anderlova","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrea","family":"Tura","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Giovanni","family":"Pacini","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Alena","family":"Sumova","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Martin","family":"Sladek","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bela","family":"Bendlova","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2022,6,6]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1600-079X.2007.00523.x","article-title":"Function and Expression of Melatonin Receptors on Human Pancreatic Islets","volume":"44","author":"Ramracheya","year":"2008","journal-title":"J Pineal Res"},{"key":"B2","doi-asserted-by":"publisher","DOI":"10.1038\/ng.288","article-title":"Common Variant in MTNR1B Associated With Increased Risk of Type 2 Diabetes and Impaired Early Insulin Secretion","volume":"41","author":"Lyssenko","year":"2009","journal-title":"Nat Genet"},{"key":"B3","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0050107","article-title":"Association Between the Melatonin Receptor 1B Gene Polymorphism on the Risk of Type 2 Diabetes, Impaired Glucose Regulation: A Meta-Analysis","volume":"7","author":"Xia","year":"2012","journal-title":"PLos One"},{"key":"B4","doi-asserted-by":"publisher","DOI":"10.1038\/s41588-018-0241-6","article-title":"Fine-Mapping Type 2 Diabetes Loci to Single-Variant Resolution Using High-Density Imputation and Islet-Specific Epigenome Maps","volume":"50","author":"Mahajan","year":"2018","journal-title":"Nat Genet"},{"key":"B5","doi-asserted-by":"publisher","DOI":"10.1016\/j.cmet.2016.04.009","article-title":"Increased Melatonin Signaling Is a Risk Factor for Type 2 Diabetes","volume":"23","author":"Tuomi","year":"2016","journal-title":"Cell Metab"},{"key":"B6","doi-asserted-by":"publisher","DOI":"10.1038\/ng.3437","article-title":"DIAbetes Genetics Replication And Meta-Analysis (DIAGRAM) Consortium. 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