Phenotypic features, prevalence of KCNJ11-MODY in Chinese patients with early-onset diabetes and a literature review.

OBJECTIVE: Gain-of-function (GOF) variants of KCNJ11 cause neonate diabetes and maturity-onset diabetes of the young (KCNJ11-MODY), while loss-of-function (LOF) variants lead to hyperinsulinemia hypoglycemia and subsequent diabetes. Given the limited research of KCNJ11-MODY, we aimed to analyse its phenotypic features and prevalence in Chinese patients with early-onset type 2 diabetes (EOD). DESIGN, PATIENTS AND MEASUREMENTS: We performed next-generation sequencing on 679 Chinese EOD patients to screen for KCNJ11 exons variants. Bioinformatics prediction and the American College of Medical Genetics and Genomics guidelines was used to determine the pathogenicity and diagnosed KCNJ11-MODY. A literature review was conducted to investigate the phenotypic features of KCNJ11-MODY. RESULTS: We identified six predicted deleterious rare variants in six EOD patients (0.88%). They were classified as uncertain significance (variant of uncertain significance [VUS]), but more common in this EOD cohort than a general Chinese population database, however, without significant difference (53/10,588, 0.50%) (p = .268). Among 80 previously reported patients with KCNJ11-MODY, 23.8% (19/80) carried 9 (32.1%) LOF variants, who had significantly older age at diagnosis, higher birthweight and higher fasting C-peptide compared to patients with GOF variants. Many patients carrying VUS were not correctly diagnosed. CONCLUSIONS: Some rare variants of KCNJ11 might contribute to the development of Chinese EOD, although available evidence has not enough power to support them as cause of KCNJ11-MODY. The clinical features of LOF variants were different from GOF variants in KCNJ11-MODY patients. It is necessary to evaluate the pathogenicity of VUS through function experiments.

Association Study of CACNA1D, KCNJ11, KCNQ1, and CACNA1E Single-Nucleotide Polymorphisms with Type 2 Diabetes Mellitus.

Type 2 diabetes mellitus (T2DM) is a complex chronic disease characterized by decreased insulin secretion and the development of insulin resistance. Previous genome-wide association studies demonstrated that single-nucleotide polymorphisms (SNPs) present in genes coding for ion channels involved in insulin secretion increase the risk of developing this disease. We determined the association of 16 SNPs found in CACNA1D, KCNQ1, KCNJ11, and CACNA1E genes and the increased probability of developing T2DM. In this work, we performed a case-control study in 301 Mexican adults, including 201 cases with diabetes and 100 controls without diabetes. Our findings indicate a moderate association between T2DM and the C allele, and the C/C genotype of rs312480 within CACNA1D. The CAG haplotype surprisingly showed a protective effect, whereas the CAC and CGG haplotypes have a strong association with T2DM. The C allele and C/C genotype of rs5219 were significantly associated with diabetes. Also, an association was observed between diabetes and the A allele and the A/A genotype of rs3753737 and rs175338 in CACNA1E. The TGG and CGA haplotypes were also found to be significantly associated. The findings of this study indicate that the SNPs examined could serve as a potential diagnostic tool and contribute to the susceptibility of the Mexican population to this disease.

Molecular Dynamics Simulation of Kir6.2 Variants Reveals Potential Association with Diabetes Mellitus.

Diabetes mellitus (DM) represents a problem for the healthcare system worldwide. DM has very serious complications such as blindness, kidney failure, and cardiovascular disease. In addition to the very bad socioeconomic impacts, it influences patients and their families and communities. The global costs of DM and its complications are huge and expected to rise by the year 2030. DM is caused by genetic and environmental risk factors. Genetic testing will aid in early diagnosis and identification of susceptible individuals or populations using ATP-sensitive potassium (KATP) channels present in different tissues such as the pancreas, myocardium, myocytes, and nervous tissues. The channels respond to different concentrations of blood sugar, stimulation by hormones, or ischemic conditions. In pancreatic cells, they regulate the secretion of insulin and glucagon. Mutations in the KCNJ11 gene that encodes the Kir6.2 protein (a major constituent of KATP channels) were reported to be associated with Type 2 DM, neonatal diabetes mellitus (NDM), and maturity-onset diabetes of the young (MODY). Kir6.2 harbors binding sites for ATP and phosphatidylinositol 4,5-diphosphate (PIP2). The ATP inhibits the KATP channel, while the (PIP2) activates it. A Kir6.2 mutation at tyrosine330 (Y330) was demonstrated to reduce ATP inhibition and predisposes to NDM. In this study, we examined the effect of mutations on the Kir6.2 structure using bioinformatics tools and molecular dynamic simulations (SIFT, PolyPhen, SNAP2, PANTHER, PhD&SNP, SNP&Go, I-Mutant, MuPro, MutPred, ConSurf, HOPE, and GROMACS). Our results indicated that M199R, R201H, R206H, and Y330H mutations influence Kir6.2 structure and function and therefore may cause DM. We conclude that MD simulations are useful techniques to predict the effects of mutations on protein structure. In addition, the M199R, R201H, R206H, and Y330H variant in the Kir6.2 protein may be associated with DM. These results require further verification in protein-protein interactions, Kir6.2 function, and case-control studies.

Genotype-phenotype correlation of KATP channel gene defects causing permanent neonatal diabetes in Indian patients.

BACKGROUND: There are very few reports pertaining to Indian patients with neonatal diabetes mellitus (NDM). Activating or gain of function mutations of KATP channel genes namely KCNJ11 and ABCC8 are most predominant cause of permanent neonatal diabetes mellitus (PNDM). OBJECTIVES: To identify the genotype-phenotype correlation of KATP channel gene defects in a large series of (n = 181) Indian PNDM patients. METHODS: Direct sequencing of all exons of KCNJ11 and ABCC8 genes in all 181 patients with PNDM were performed. Clinical and biochemical data were collected. RESULTS: We have identified the molecular basis of KATP -NDM in 39 out of 181 patients (22%). Of these, 20 had KCNJ11 mutations and 19 had ABCC8 mutations, thus comprising 51% of KCNJ11 and 49% of ABCC8. There were four novel mutations (D1128Tfs*16, Y1287C, S1422T, and H1537R) in ABCC8 gene. Three patients with KCNJ11 mutations had developmental delay with DEND syndrome. In patients with ABCC8 mutations developmental delay was seen in seven out of 19 (36.8%). Of this, three patients (15.7%) had DEND phenotype and four (21%) had iDEND. Of the 39 patients, 33 (84%) patients were shifted to sulfonylurea therapy (glibenclamide). Of this, 19(57.5%) patients harbored KCNJ11 mutations and 14(42.1%) ABCC8 mutations. CONCLUSIONS: This is the first largest study in NDM patients in India demonstrating the importance of KATP channel gene mutation screening in PNDM and efficacy of glibenclamide for Indian patients with KATP -PNDM. The success rate of transfer is more in patients with KCNJ11 mutations compared with those with ABCC8 mutations.

Update of variants identified in the pancreatic ß-cell KATP channel genes KCNJ11 and ABCC8 in individuals with congenital hyperinsulinism and diabetes.

The most common genetic cause of neonatal diabetes and hyperinsulinism is pathogenic variants in ABCC8 and KCNJ11. These genes encode the subunits of the ß-cell ATP-sensitive potassium channel, a key component of the glucose-stimulated insulin secretion pathway. Mutations in the two genes cause dysregulated insulin secretion; inactivating mutations cause an oversecretion of insulin, leading to congenital hyperinsulinism, whereas activating mutations cause the opposing phenotype, diabetes. This review focuses on variants identified in ABCC8 and KCNJ11, the phenotypic spectrum and the treatment implications for individuals with pathogenic variants.

ATP binding without hydrolysis switches sulfonylurea receptor 1 (SUR1) to outward-facing conformations that activate KATP channels.

Neuroendocrine-type ATP-sensitive K+ (KATP) channels are metabolite sensors coupling membrane potential with metabolism, thereby linking insulin secretion to plasma glucose levels. They are octameric complexes, (SUR1/Kir6.2)4, comprising sulfonylurea receptor 1 (SUR1 or ABCC8) and a K+-selective inward rectifier (Kir6.2 or KCNJ11). Interactions between nucleotide-, agonist-, and antagonist-binding sites affect channel activity allosterically. Although it is hypothesized that opening these channels requires SUR1-mediated MgATP hydrolysis, we show here that ATP binding to SUR1, without hydrolysis, opens channels when nucleotide antagonism on Kir6.2 is minimized and SUR1 mutants with increased ATP affinities are used. We found that ATP binding is sufficient to switch SUR1 alone between inward- or outward-facing conformations with low or high dissociation constant, KD , values for the conformation-sensitive channel antagonist [3H]glibenclamide ([3H]GBM), indicating that ATP can act as a pure agonist. Assembly with Kir6.2 reduced SUR1's KD for [3H]GBM. This reduction required the Kir N terminus (KNtp), consistent with KNtp occupying a "transport cavity," thus positioning it to link ATP-induced SUR1 conformational changes to channel gating. Moreover, ATP/GBM site coupling was constrained in WT SUR1/WT Kir6.2 channels; ATP-bound channels had a lower KD for [3H]GBM than ATP-bound SUR1. This constraint was largely eliminated by the Q1179R neonatal diabetes-associated mutation in helix 15, suggesting that a "swapped" helix pair, 15 and 16, is part of a structural pathway connecting the ATP/GBM sites. Our results suggest that ATP binding to SUR1 biases KATP channels toward open states, consistent with SUR1 variants with lower KD values causing neonatal diabetes, whereas increased KD values cause congenital hyperinsulinism.

Congenital hyperinsulinism: management and outcome, a single tertiary centre experience.

Hyperinsulinemic hypoglycaemia (HH) is the most frequent cause of persistent hypoglycaemia in neonates and infants. The most severe forms of HH are inherited and referred to as congenital hyperinsulinism (CHI). Diazoxide is the mainstay of treatment, with surgery being an option in appropriate cases. To describe the management and outcome of patients with CHI within our service. Children referred to or attending HH clinic between 2009 and 2017 were identified. Clinical course, genetics and interventions were documented. A total of 39 children were identified, and seven patients with secondary and syndromic HH were excluded. Most were born with an appropriate weight for gestational age (62.5%). Diazoxide was started in all patients; however, 7 did not respond and required octreotide/continuous feeding, with 6/7 requiring surgery. Genetic mutations were detected in 12/32 (37.5%). Hyperinsulinism resolved in conservatively treated patients within 12 months in 11/32 (34.3%) compared to 14/32 (43.7%) requiring more than 12 months of medication. A total of 7 patients underwent pancreatectomy.Conclusion: Although LGA and SGA are risk factors, most babies in our cohort are born AGA. A genetic mutation does not exclude medical remission; long-term conservative treatment of CHI is feasible as surgery does not guarantee complete remission.What is Known:•Congenital hyperinsulinism (CHI) is a clinically and genetically heterogeneous disorder that is the most common cause of permanent hypoglycaemia in infants and children.•Identification of genetic mutations and the use of 18F-DOPA PET scan when feasible lead to better outcomes.What is New:•The study describes clinical criteria, management and outcome of large number of patients with CHI in single tertiary centre.•Conservative treatment is feasible without the need for surgery, with HH resolving in over 30% within 12 months, irrespective of genetic mutation.

Comparison of diabetes phenotype in children and their mothers with permanent neonatal diabetes mellitus carrying the same KCNJ11 variants.

Objective. Mutations of the KCNJ11 gene are the most common cause of the permanent neonatal diabetes mellitus (PNDM). Majority of people with KNCJ11-PNDM have a de-novo mutation. We aimed to compare diabetes phenotype in two children and their mothers with PNDM carrying the same sulfonylurea-sensitive KCNJ11 variants.Methods. We have compared glibenclamide (sulfonylurea) dose, C-peptide, and HbA1c serum levels in two children and their mothers with PNDM up to 5.5-year follow-up. All of them were carrying a heterozygous activating KCNJ11 pathogenic variant (p.R201H in Family 1 or p.H46Y in Family 2). The mothers were initially treated with insulin and successfully switched to sulfonylurea at the age of 24 and 11 years, respectively. Both children were treated with sulfonylurea since the diagnosis of PNDM.Results. Glibenclamide dose was similar in both children (0.02-0.03 mg/kg/day), but lower compared to their mothers (0.1-0.4 mg/kg/day) (p<0.002). Fasting serum C-peptide levels were also lower in children (70-210 pmol/l) than in their mothers (263-720 pmol/l) (p<0.002), but no significant differences were observed in postprandial C-peptide levels. HbA1c was lower only in the son of SVK4 (Family 2) compared to his mother, as she had poor adherence to the sulfonylurea therapy during the first years after the sulfonylurea switch.Conclusions. Evaluation of the treatment in people with sulfonylurea-sensitive KNCJ11-PNDM should respect the age of patients together with the type of mutation and duration of diabetes at therapy start and may differ within one family.

Association of growth traits with a structural variation downstream of the KCNJ11 gene: a large population-based study in chickens.

1. The potassium voltage-gated channel subfamily J member 11 gene (KCNJ11) is involved in the insulin secretion pathway. Studies have shown that mutation in this gene is associated with muscle weakness. The objective of the present study was to establish the association between KCNJ11 gene polymorphism and chicken growth performance and to analyse its expression pattern. 2. A novel 163-bp insertion/deletion (indel) polymorphism was identified in the region downstream of the KCNJ11 gene in 2330 individuals from ten populations by polymerase chain reaction (PCR). An F2 resource population was used to investigate the genetic effects of the chicken KCNJ11 gene. Association analysis showed that the indel was significantly associated with chicken growth traits and that the phenotypic value of the ins-ins (II) genotype is higher than that of the ins-del (ID) and del-del (DD) genotypes. 3. Gene expression for different genotypes showed that birds carrying the II allele had a higher expression level than the DD genotypes. Analysis of tissue and spatiotemporal expression patterns indicated that the KCNJ11 gene was highly expressed in muscle tissues, with the highest levels in muscle tissue at one week of age, and that a 10% crude protein diet reduced the expression of this gene, average daily gain and muscle fibre diameter. 4. The results suggested that this novel 163-bp indel has the potential to become a new target for marker-assisted selection.

ADIPOQ, KCNJ11 and TCF7L2 polymorphisms in type 2 diabetes in Kyrgyz population: A case-control study.

The aim of this study was to ascertain the polymorphic markers profile of ADIPOQ, KCNJ11 and TCF7L2 genes in Kyrgyz population and to analyze the association of polymorphic markers and combinations of ADIPOQ gene's G276T locus, KCNJ11 gene's Glu23Lys locus and TCF7L2 gene's VS3C>T locus with type two diabetes (T2D) in Kyrgyz population. In this case-control study, 114 T2D patients 109 non-diabetic participants were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Two individual polymorphisms (ADIPOQ rs1501299, KCNJ11 rs5219) were found to be associated with T2D. We found two (Lys23Lys/CC and Glu23Lys/CT) of the overall nine combinations, which were more prevalent in T2D group compared to controls (χ2 = 4.21, P = 0.04). Lys23Lys/CC combination was associated with a 2.65-fold increased likelihood of T2D (OR = 2.65, 95% CI 1.12-6.28), whereas the Glu23Lys/CT combination also increased such likelihood (OR = 3.88, 95% CI 1.27-11.91). This study demonstrated some association of 276T allele and ADIPOQ gene G276T heterozygous genotype as well as KCNJ11 gene 23Lys allele with T2D in ethnic Kyrgyz, but study results should be interpreted with caution because of the limited statistical power.

Association of KCNJ11 rs5219 gene polymorphism with type 2 diabetes mellitus in a population of Syria: a case-control study.

BACKGROUND: Type 2 diabetes mellitus is believed to be a polygenic disorder that develops as a result of a complex interaction between multiple genes and environmental factors. KCNJ11 gene encodes a Kir6.2 protein which forms the inner section of the potassium channels in pancreatic beta cells. Several studies found that KCNJ11 polymorphism increases T2DM risk. Our study aimed to investigate the association between rs5219 polymorphism of the KCNJ11 gene and T2DM in Syrian patients. METHODS: This case-control study involved 75 T2DM patients and 63 healthy controls. The KCNJ11 rs5219 polymorphism was genotyped by Restriction Fragment Length Polymorphism (RFLP). RESULTS: The frequency of the risk allele K was similar between the two groups (38.7% vs. 38.1%, P = 0.132). The frequency of the KK genotype was higher among the patients' group (16% vs. 4.8%), and the frequency of the EK genotype was higher among the control group (45.3% vs. 66.6%); however, the differences were statistically insignificant. The KK genotype was significantly associated with T2DM in the recessive model with an OR of 3.81 (95% CI 1.024-14.17, P = 0.035). CONCLUSIONS: This study showed that rs5219 polymorphism of the KCNJ11 gene is an important risk factor for type 2 diabetes mellitus in a sample of the Syrian population.

Precision Medicine: Long-Term Treatment with Sulfonylureas in Patients with Neonatal Diabetes Due to KCNJ11 Mutations.

PURPOSE OF REVIEW: The goal of this review is to provide updates on the safety and efficacy of long-term sulfonylurea use in patients with KCNJ11-related diabetes. Publications from 2004 to the present were reviewed with an emphasis on literature since 2014. RECENT FINDINGS: Sulfonylureas, often taken at high doses, have now been utilized effectively in KCNJ11 patients for over 10 years. Mild-moderate hypoglycemia can occur, but in two studies with a combined 975 patient-years on sulfonylureas, no severe hypoglycemic events were reported. Improvements in neurodevelopment and motor function after transition to sulfonylureas continue to be described. Sulfonylureas continue to be an effective, sustainable, and safe treatment for KCNJ11-related diabetes. Ongoing follow-up of patients in research registries will allow for deeper understanding of the facilitators and barriers to long-term sustainability. Further understanding of the effect of sulfonylurea on long-term neurodevelopmental outcomes, and the potential for adjunctive therapies, is needed.

Glibenclamide oral suspension: Suitable and effective in patients with neonatal diabetes.

BACKGROUND: Results of genetic have led to off-label glibenclamide treatment in patients with neonatal diabetes (NDM) because of potassium channel mutations. No pediatric form of glibenclamide was available. Glibenclamide was designated an orphan drug designation for NDM and a suspension was developed. As a part of the pediatric plan investigation, we assessed its acceptability, efficiency, and safety. METHODS: In this Phase II, prospective, non-randomized, single-center study, patient received glibenclamide tablets for 1 month then the suspension for 3 months. We assessed acceptability using hedonic scales and patient questionnaires, effectiveness using glycated hemoglobin (HbA1C) assays and safety based on hypo and hyperglycemia, and other adverse events. RESULTS: We included 10 patients (0.1-16.2 years, 6 < 5 years) were included. Younger patients preferred the suspension and older the tablets. All parents were satisfied with the ease of suspension administration. The parents of 5 of 6 younger children preferred the suspension over the tablets and kept it. Switching from tablets to suspension did not affect the excellent metabolic control (median HbA1c change, -0.40%, [-1.3% to 0.5%] P = 0.08). Median frequencies of hypoglycemia and hyperglycemia were less than 5% of routine blood glucose assays and were similar with both dosage forms. Two patients each experienced one episode of hypoglycemia below 35 mg/dL highlighting the need for dosage titration when switching from tablets to suspension. Transient and non-severe abdominal pain or diarrhea occurred in three patients. None of the patients discontinued the treatment. CONCLUSION: The glibenclamide oral suspension Amglidia, the first anti-diabetic drug specifically developed for pediatric patients, is acceptable, effective, and safe in patients with NDM (NCT02375828). CLINICAL TRIAL REGISTRATION: Glibentek in Patients with Neonatal Diabetes Secondary to Mutations in K + -ATP Channels, clinicaltrials.gov, NCT02375828, https://clinicaltrials.gov/ct2/show/NCT02375828.

Functional characterization of activating mutations in the sulfonylurea receptor 1 (ABCC8) causing neonatal diabetes mellitus in Asian Indian children.

BACKGROUND: Gain-of-function of ATP-sensitive K+ (KATP ) channels because of mutations in the genes encoding SUR1 (ABCC8) or Kir6.2 (KCNJ11) is a major cause of neonatal diabetes mellitus (NDM). Our aim is to determine molecular defects in KATP channels caused by ABCC8 mutations in Asian Indian children with NDM by in vitro functional studies. METHODS: Wild-type (WT; NM_000352.4) or mutant sulfonylurea receptor 1 (SUR1) and Kir6.2 were co-expressed in COSm6 cells. Biogenesis efficiency and surface expression of mutant channels were assessed by immunoblotting and immunostaining. The response of mutant channels to cytoplasmic ATP and ADP was assessed by inside-out patch-clamp recordings. The response of mutant channels to known KATP inhibitors in intact cells were determined by 86 Rb efflux assays. RESULTS: Five SUR1 missense mutations, D212Y, P254S, R653Q, R992C, and Q1224H, were studied and showed increased activity in MgATP/MgADP. Two of the mutants, D212Y and P254S, also showed reduced response to ATP4- inhibition, as well as markedly reduced surface expression. Moreover, all five mutants were inhibited by the KATP channel inhibitors glibenclamide and carbamazepine. CONCLUSIONS: The study shows the mechanisms by which five SUR1 mutations identified in Asian Indian NDM patients affect KATP channel function to cause the disease. The reduced ATP4- sensitivity caused by the D212Y and P254S mutations in the L0 of SUR1 provides novel insight into the role of L0 in channel inhibition by ATP. The results also explain why sulfonylurea therapy is effective in two patients and inform how it should be effective for the other three patients.

Hypoglycemia in sulfonylurea-treated KCNJ11-neonatal diabetes: Mild-moderate symptomatic episodes occur infrequently but none involving unconsciousness or seizures.

BACKGROUND: Neonatal diabetes mellitus (NDM) caused by mutations in KCNJ11 can be successfully treated with high dose oral sulfonylureas; however, little data is available on the risk of hypoglycemia. OBJECTIVE: To determine the frequency, severity, and clinical significance of hypoglycemia in KCNJ11-related NDM. METHODS: Utilizing the University of Chicago Monogenic Diabetes Registry, parents completed an online questionnaire addressing hypoglycemia. Continuous glucose monitoring (CGM) data was available for 7 subjects. RESULTS: Thirty subjects with KCNJ11-related permanent NDM (166 patient-years on sulfonylurea) had median sulfonylurea dose of 0.39 mg/kg/day (0.24-0.88 IQR, interquartile range) with median HbA1c 5.7% (39 mmol/mol) (5.5-6.1 IQR, 37-43 mmol/mol). Hypoglycemia (<70 mg/dL) was reported monthly once or less frequently in 89.3% of individuals, but 3 (10.7%) reported once weekly or more. Of all hypoglycemic episodes reported, none involved seizures or unconsciousness and thus did not meet the current ISPAD definition of severe hypoglycemia. Seven individuals wore a CGM for a total of 912 hours with blood sugars falling below 70 mg/dL for 5.8% of the time recorded, similar to ranges reported for people without diabetes. CONCLUSIONS: In our cohort of KCNJ11-related permanent NDM, hypoglycemia is infrequent and mild despite the high doses of sulfonylurea used and near-normal level of glycemic control. Long-term follow-up on larger numbers will be required to clarify the incidence and determinants of hypoglycemia in this unique population.

CYP2C9*3 gene variant contributes independently to glycaemic control in patients with type 2 diabetes treated with glibenclamide.

WHAT IS KNOWN AND OBJECTIVE: Glibenclamide is a prescribed glucose-lowering medication for diabetes, but there are interindividual variations in the therapeutic response. In this cross-sectional study, the aim was to explore the association of genetic variants in CYP2C9, ABCC8, KCNJ11 and TCF7L2 with good glycaemic control in Mexican type 2 diabetes (T2D) treated with glibenclamide. METHODS: Patients with T2D receiving treatment with glibenclamide or glibenclamide plus metformin were included. Patients with A1C ≤ 7% were considered to have good glycaemic control, whereas patients with A1C ≥ 8% were considered having poor glycaemic control. Genotyping was performed by real-time PCR using TaqMan probes for the genetic variants. Association was performed by calculating OR with 95% confidence intervals (95% CI). For the multivariate analysis, a multiple logistic regression was performed including the confounding variables age, exercised, BMI, glibenclamide dose, time with T2D and concomitant metformin. RESULTS AND DISCUSSION: Four hundred and four patients were included in the study, median age of the participants was 50 years (IQR 11.0), the median time with disease was 6 years (IQR 8.0), 118 (29.2%) were men, and 243 (60.1%) received glibenclamide in combination with metformin. CYP2C9*3 variant was associated with good glycaemic control (OR = 2.747 [95% CI, 1.194-6.324]), whereas the variants, CYP2C9*2, TCF7L2 rs7903146 and rs12255372, ABCC8 rs757110 and KCNJ11 rs5219, were not. In the multivariate analysis, the CYP2C9*3 variant maintained its association (OR = 2.779 [95% CI, 1.142-6.763]). WHAT IS NEW AND CONCLUSION: The findings suggest that CYP2C9*3 genetic variant independently contributes to good glycaemic control of patients with type 2 diabetes treated with glibenclamide.

Genetic polymorphisms in KCNJ11 (E23K, rs5219) and SDF-1ß (G801A, rs1801157) genes are associated with the risk of type 2 diabetes mellitus.

Background Type 2 diabetes mellitus (T2DM) is a global major health problem resulting from interaction of environmental and genetic factors, examples of the latter being KCNJ11 (coding for part of the ATP-sensitive potassium channel) and SDF-1ß (coding for chemokine CXCL12). Our case-control study was conducted to assess whether recessive, dominant or additive genotype model associations of KCNJ11 (E23K, rs5219) and SDF-1ß (G801A, rs1801157) were more strongly linked to type 2 diabetes. Subjects & Methods Genetic polymorphism analysis was performed by polymerase chain reaction-restriction fragment length polymorphism. Alleles and genotype frequencies between 200 cases and 200 controls were determined and compared. Results The dominant (EE v EK + KK, p = 0.022) and additive (EK v EE + KK, p = 0.021) models, but not the recessive model (KK v EE + EK, p = 0.727) of KCNJ11 were linked to diabetes. Similarly, the dominant (GG v GA + AA, p < 0.001) and additive (AG v GG + AA, p=<0.001) models, but not the recessive model (AA v AG + GG, p = 0.430) of SDF-1ß were linked to diabetes. The A allele (p = 0.006) of SDF-1ß was protective against the risk of T2DM. Conclusion Both dominant and additive models in both KCNJ11 (E23K, rs5219) and SDF-1ß (G801A, rs1801157) genetic polymorphisms are significantly associated with type 2 diabetes.

Mutation screening of INS and KCNJ11 genes in Taiwanese children with type 1B diabetic onset before the age of 5 years.

Type 1 diabetes (T1D) is caused by ß-cell destruction, usually leading to absolute insulin deficiency. T1D is a heterogeneous disease and is divided into two subtypes according to the presence or absence of pancreatic autoantibodies: type 1A (immune mediated) and type 1B (idiopathic). Genes such as KCNJ11 or INS, which play key roles in ß-cell function, provide some insight into the pathogenesis of type 1B diabetes. In this study, we screened 110 Taiwanese children (61 males and 49 females) with T1D onset before the age of 5 years for mutations of INS and KCNJ11. We identified one missense heterozygous mutation in KCNJ11 (c.989A>G, p.Y330C) and no INS mutations among 28 probands. This is the first study to screen patients with autoantibody-negative T1D diagnosed before the age of 5 years for INS and KCNJ11 mutations in Taiwan. Although KCNJ11 mutations are always reported in patients with permanent neonatal diabetes, this gene mutation can be detected after 6 months of age. Further studies in other patients with type 1B diabetes and their families are required to elucidate the contributions of the KCNJ11 mutation to the T1D phenotype.

[Effects of exercise intervention on the relationship between KCNJ11 gene polymorphism and glucose and lipid metabolism in pre-diabetes mellitus].

OBJECTIVE: To investigate the effect of exercise intervention on the relationship between KCNJ11 gene polymorphism and glycolipid metabolism in pre-diabetic population. METHODS: From January 2017 to March 2017, 5 communities were selected by stratified cluster random sampling method in Liaocheng City, Shandong Province, and 46 cases of pre-diabetes'data were collected through public welfare physical examination activities. The exercise intervention was performed for 8 weeks with their consent and cooperation. The polymorphism of KCNJ11 gene and the index of glucose and lipid metabolism were detected before and after exercise intervention, and the correlation between them was also discussed. RESULTS: After 8 weeks of exercise intervention, 2 h postprandial blood glucose, fasting glucose, glycosylated hemoglobin and four indicators of blood lipids were significantly improved in pre-diabetes populations(P<0. 05). KCNJ11 gene polymorphism analysis showed that the TG, TC and HDL-C lipid metabolism indexes of CC genotype in rs5219 locus were more significant than those of TT and CT genotypes(t=2. 635, 3. 213 and 2. 048, P=0. 012, 0. 003 and 0. 048)after exercise intervention, the changes of FPG and HbA lc glucose metabolism indexes in GG genotype population of rs2285676 locus were more significant than those in AA and AG genotypes(t=2. 236 and 2. 062, P=0. 034 and 0. 049). CONCLUSION: The CC genotype of the KCNJ11 gene rs5219 site and the GG genotype of rs2285676 site can be used as the dominant gene to evaluate the change of glucose lipid metabolism in the early stage of diabetes intervention.

Precision diabetes: learning from monogenic diabetes.

The precision medicine approach of tailoring treatment to the individual characteristics of each patient or subgroup has been a great success in monogenic diabetes subtypes, MODY and neonatal diabetes. This review examines what has led to the success of a precision medicine approach in monogenic diabetes (precision diabetes) and outlines possible implications for type 2 diabetes. For monogenic diabetes, the molecular genetics can define discrete aetiological subtypes that have profound implications on diabetes treatment and can predict future development of associated clinical features, allowing early preventative or supportive treatment. In contrast, type 2 diabetes has overlapping polygenic susceptibility and underlying aetiologies, making it difficult to define discrete clinical subtypes with a dramatic implication for treatment. The implementation of precision medicine in neonatal diabetes was simple and rapid as it was based on single clinical criteria (diagnosed <6 months of age). In contrast, in MODY it was more complex and slow because of the lack of single criteria to identify patients, but it was greatly assisted by the development of a diagnostic probability calculator and associated smartphone app. Experience in monogenic diabetes suggests that successful adoption of a precision diabetes approach in type 2 diabetes will require simple, quick, easily accessible stratification that is based on a combination of routine clinical data, rather than relying on newer technologies. Analysing existing clinical data from routine clinical practice and trials may provide early success for precision medicine in type 2 diabetes.