Non-immune diabetes mellitus in children due to heterozygous mutations in the glucokinase gene (GCK-MODY): data of 144 patients

BACKGROUND: Monogenic diabetes mellitus (MDM) is a rare form of diabetes mellitus (DM) which caused by one or more mutations in one of the genes that cause pancreatic β-cell dysfunction. Despite the sufficient knowledge of the most common subtypes of MODY, cases of MDM are undiagnosed and classified as type 1 diabetes mellitus and type 2 diabetes mellitus.AIM: To study the clinical, laboratory characteristics, as well as age-related features of GCK-MODY in children.MATERIALS AND METHODS: The studied population is patients with GCK-MODY under the age of 18 years. The diagnosis was confirmed by genetic test, a heterozygous mutation was identificated in the GCK gene.RESULTS: MODY-GCK was verified in 144 patients (131 probands and 13 siblings) under the age of 18 years. Missense mutations were detected in 80.2% (n=105). Mutation was detected in one case in 59.6%. The most common missense mutations were p.G261R (n=7) and p.G258C (n=6). The age of diagnosis of carbohydrate metabolism disorders was 7.6 years [4.0; 11.2]. In 72.2% carbohydrate metabolism disorders were diagnosed accidentally, in 16.7% the examination was provided due to a family history of diabetes, 11.1% had clinical symptoms of diabetes. Fasting glycemia at diagnosis was 6.8 mmol / l [6.4; 7.3], HbA1c — 6.4% [6.1; 6.7]. At examination, the level of fasting glycemia corresponded to normal values in 16.4% of patients, impaired fasting glycemia — in 57.8%, diabetic — in 25.8%. In 62.3% of patients was impaired glucose tolerance, in 18.9% — to diabetic values, and in 11.7% of patients — to a normal level at 120 minutes during the oral glucose tolerance test. A moderate positive correlation was found between the age of examination and the levels of fasting glycemia (r=0.347, p<0.01), C-peptide (r=0.656, p<0.001), and insulin (r=0.531, p<0.001). Insulin resistance (IR) (HOMA index) was detected in 21 patients (14.5%), obesity — in 6 patients (4.2%). In 9 patients (6.25%) was revealed a moderate increase in the titer of specific pancreatic antibodies (AT). The presence of IR, obesity, AT did not affect the level of HbA1c. In 92.3% diet was priscribed, in 4.2% insulin was prescribed, 2.1% — metformin, 1.4% — sulfonylureas.CONCLUSION: In children, disorders of carbohydrate metabolism in GCK-MODY are diagnosed accidentally, asymptomatically at any age from birth, and are characterized by a combination of impaired fasting glycemia and impaired glucose tolerance and, as a rule, do not require antihyperglycemic therap

MODY caused by a mutation in the insulin gene

MODY10 is a rare subtype of MODY diabetes, which caused by heterozygous mutations in the insulin gene INS. There are single descriptions of families with MODY-INS or MODY10 in the literature, its clinical course is not well understood. We present a case of MODY10 in a boy with a history of diabetes mellitus (DM) in three generations (father and paternal grandmother). Proband was diagnosed with diabetes mellitus at the age of 7 years. The glycaemia at the onset of the diabetes was 10.2 mmol/l, HbA1c — 7.6%, islet cell autoantibodies (ICA), insulin autoantibodies (IAA), glutamic acid decarboxylase antibodies (GADA) and islet tyrosine phosphatase 2 (IA2) antibodies (IA2) were not detected. According to the results of the oral glucose tolerance test, fasting blood glucose was 6.5 mmol/l, in 120 minutes 10.3 mmol/l, which corresponded to the diagnosis of impaired glucose tolerance. Diet with restriction of easily digestible carbohydrates was recommended, than gliclazide was added to the therapy, which the proband received for 3 years. At the age of 10, a deterioration in the parameters of carbohydrate metabolism was noted, which insulin therapy was added. Examination at the age of 12 revealed a decrease in C-peptide secretion. The child’s father has a similar phenotype — slowly progressive disorders of carbohydrate metabolism from 6 years old, from 10 years old — insulin therapy. A genetic test was provided, in the child and his father was detected a previously undescribed heterozygous mutation in the INS p.C31W. Thus, in our clinical case, MODY10 was characterized by a milder course than T1DM, but eventually leading to the development of insulin demand, which distinguishes it from the most common forms of MODY. Currently, there is no specific therapy, and the detection of a mutation in the INS gene does not affect therapeutic tactics, however, a correct genetic diagnosis makes it possible to predict the course of diabetes and provide genetic counseling to the family

Association between TCF7L2 gene polymorphisms and susceptibility to Type 2 Diabetes Mellitus: a large Human Genome Epidemiology (HuGE) review and meta-analysis

<p>Abstract</p> <p>Background</p> <p>Transcription factor 7-like 2 (<it>TCF7L2</it>) has been shown to be associated with type 2 diabetes mellitus (T2MD) in multiple ethnic groups in the past two years, but, contradictory results were reported for Chinese and Pima Indian populations. The authors then performed a large meta-analysis of 36 studies examining the association of type 2 diabetes mellitus (T2DM) with polymorphisms in the <it>TCF7L2 </it>gene in various ethnicities, containing rs7903146 C-to-T (IVS3C>T), rs7901695 T-to-C (IVS3T>C), a rs12255372 G-to-T (IVS4G>T), and rs11196205 G-to-C (IVS4G>C) polymorphisms and to evaluate the size of gene effect and the possible genetic mode of action.</p> <p>Methods</p> <p>Literature-based searching was conducted to collect data and three methods, that is, fixed-effects, random-effects and Bayesian multivariate mete-analysis, were performed to pool the odds ratio (<it>OR</it>). Publication bias and study-between heterogeneity were also examined.</p> <p>Results</p> <p>The studies included 35,843 cases of T2DM and 39,123 controls, using mainly primary data. For T2DM and IVS3C>T polymorphism, the Bayesian <it>OR </it>for TT homozygotes and TC heterozygotes versus CC homozygote was 1.968 (95% credible interval (<it>CrI</it>): 1.790, 2.157), 1.406 (95% <it>CrI</it>: 1.341, 1.476), respectively, and the population attributable risk (PAR) for the TT/TC genotypes of this variant is 16.9% for overall. For T2DM and IVS4G>T polymorphism, TT homozygotes and TG heterozygotes versus GG homozygote was 1.885 (95%<it>CrI</it>: 1.698, 2.088), 1.360 (95% <it>CrI</it>: 1.291, 1.433), respectively. Four <it>OR</it>s among these two polymorphisms all yielded significant between-study heterogeneity (P < 0.05) and the main source of heterogeneity was ethnic differences. Data also showed significant associations between T2DM and the other two polymorphisms, but with low heterogeneity (<it>P </it>> 0.10). Pooled <it>OR</it>s fit a codominant, multiplicative genetic model for all the four polymorphisms of <it>TCF7L2 </it>gene, and this model was also confirmed in different ethnic populations when stratification of IVS3C>T and IVS4G>T polymorphisms except for Africans, where a dominant, additive genetic mode is suggested for IVS3C>T polymorphism.</p> <p>Conclusion</p> <p>This meta-analysis demonstrates that four variants of <it>TCF7L2 </it>gene are all associated with T2DM, and indicates a multiplicative genetic model for all the four polymorphisms, as well as suggests the <it>TCF7L2 </it>gene involved in near 1/5 of all T2MD. Potential gene-gene and gene-environmental interactions by which common variants in the <it>TCF7L2 </it>gene influence the risk of T2MD need further exploration.</p

A new type 1 diabetes susceptibitity locus containing the catalase gene (chromosome 11p13) in a Russian population

Background. Oxidative stress is involved in the origin of type 1 diabetes. Low efficiency of the scavenging antioxidant system has been shown to be related to the pathogenesis of the disease. This, therefore suggests that genes encoding catalase and other antioxidant enzymes may implicate in the development of type 1 diabetes. Methods. Nine microsatellite markers that cover about 10 megabases around the catalase (CAT) gene on chromosome 11p13 were analyzed using polymerase chain reaction (PCR) and fluorescence-based genotyping on an automatic DNA sequencer. We also evaluated three single-nucleotide polymorphisms (SNP) within genes encoding catalase (T1667T and C(-262)T dimorphism) and ETS homologous factor (EHF) (C255T SNP) using a PCR-restriction fragment-length polymorphism approach. Multipont linkage analysis in 37 affected sibling pairs was performed using GENEHUNTER 2.1. We examined the markers for association with the disease by transmission disequilibrium tests in 57 discordant sibling pairs and by a case-control study in 258 unrelated healthy donors and 247 affected patients. Results. We obtained close-to-suggestive evidence of linkage to type I diabetes, with the maximum linkage peak between markers D11S907 and D11S2008. Analysis of three SNPs at the CAT and EHF gene located within the region of maximum linkage showed that T1667T and C(-262)T markers of the CAT gene are strongly associated with the disease. Conclusion. Our findings support evidence of a new putative type 1 diabetes susceptibility locus on chromosome 11p13 and suggest that the CAT gene may play a role in conferring susceptibility to the disorder in Russian patients