Defective functions of HNF1A variants on BCL2L1 transactivation and beta-cell growth.

Maturity-onset diabetes of the young type 3 (MODY3) is caused by mutations in a gene encoding transcription factor hepatocyte nuclear factor 1-alpha (HNF1A). Although the roles of HNF1A in regulation of hepatic and pancreatic genes to maintain glucose homeostasis were investigated, the functions of HNF1A are not completely elucidated. To better understand the functions of HNF1A, we characterized mutations of HNF1A in Thai MODY3 patients and studied the functions of wild-type HNF1A and variant proteins. We demonstrate for the first time that HNF1A upregulates transactivation of an anti-apoptotic gene BCL2 Like 1 (BCL2L1) and that all the identified HNF1A variants including p.D80V, p.R203C, p.P475L, and p.G554fsX556, reduce this ability. The four HNF1A variants impair HNF1A function in promoting INS-1 cell transition from G1 to S phase of cell cycle, which thereby retard cell growth. This finding indicates the role of HNF1A in beta-cell viability by upregulation of anti-apoptotic gene expression and also reaffirms its role in beta-cell growth through cell cycle control.

Quantitative Proteomics Reveals Differences in the Response of Neutrophils Isolated from Healthy or Diabetic Subjects to Infection with Capsule-Variant Burkholderia thailandensis.

In Thailand, diabetes mellitus is the most significant risk factor for melioidosis, a severe disease caused by Burkholderia pseudomallei. In this study, neutrophils isolated from healthy or diabetic subjects were infected with B. thailandensis E555, a variant strain with a B. pseudomallei-like capsular polysaccharide used here as a surrogate micro-organism for B. pseudomallei. At 2 h post-infection, neutrophil proteins were subjected to 4-plex iTRAQ-based comparative proteomic analysis. A total of 341 proteins were identified in two or more samples, of which several proteins involved in oxidative stress and inflammation were enriched in infected diabetic neutrophils. We validated this finding by demonstrating that infected diabetic neutrophils generated significantly elevated levels of pro-inflammatory cytokines TNFα, IL-6, IL-1ß, and IL-17 compared to healthy neutrophils. Our data also revealed that infected neutrophils from healthy or diabetic individuals undergo apoptotic cell death at distinctly different rates, with infected diabetic neutrophils showing a diminished ability to delay apoptosis and an increased likelihood of undergoing a lytic form of cell death, compared to infected neutrophils from healthy individuals. Increased expression of inflammatory proteins by infected neutrophils could contribute to the increased susceptibility to infection and inflammation in diabetic patients in melioidosis-endemic areas.

Impact of KCNQ1, CDKN2A/2B, CDKAL1, HHEX, MTNR1B, SLC30A8, TCF7L2, and UBE2E2 on risk of developing type 2 diabetes in Thai population.

BACKGROUND: Several type 2 diabetes (T2D) susceptibility loci identified via genome-wide association studies were found to be replicated among various populations. However, the influence of these loci on T2D in Thai population is unknown. The aim of this study was to investigate the influence of eight single nucleotide polymorphisms (SNPs) reported in GWA studies on T2D and related quantitative traits in Thai population. METHODS: Eight SNPs in or near the KCNQ1, CDKN2A/2B, SLC30A8, HHEX, CDKAL1, TCF7L2, MTNR1B, and UBE2E2 genes were genotyped. A case-control association study comprising 500 Thai patients with T2D and 500 ethnically-matched control subjects was conducted. Associations between SNPs and T2D were examined by logistic regression analysis. The impact of these SNPs on quantitative traits was examined by linear regression among case and control subjects. RESULTS: Five SNPs in KCNQ1 (rs2237892), CDK2A/2B (rs108116610, SLC30A8 (rs13266634), TCF7L2 (rs7903146) and MTNR1B (rs1387153) were found to be marginally associated with risk of developing T2D, with odds ratios ranging from 1.43 to 2.02 (p = 0.047 to 3.0 × 10-4) with adjustments for age, sex, and body mass index. Interestingly, SNP rs13266634 of SLC30A8 gene reached statistical significance after correcting for multiple testing (p = 0.0003) (p < 0.006 after Bonferroni correction). However, no significant association was detected between HHEX (rs1111875), CDKAL1 (rs7756992), or UBE2E2 (rs7612463) and T2D. We also observed association between rs10811661 and both waist circumference and waist-hip ratio (p = 0.007 and p = 0.023, respectively). In addition, rs13266634 in SLC30A8 was associated with glycated hemoglobin (p = 0.018), and rs7903146 in TCF7L2 was associated with high-density lipoprotein cholesterol level (p = 0.023). CONCLUSION: Of the eight genes included in our analysis, significant association was observed between KCNQ1, CDKN2A/2B, SLC30A8, TCF7L2, and MTNR1B loci and T2D in our Thai study population. Of these, CDKN2A/2B, SLC30A8, and TCF7L2 genes were also significantly associated with anthropometric, glycemic and lipid characteristics. Larger cohort studies and meta-analyses are needed to further confirm the effect of these variants in Thai population.

PAX4 R192H and P321H polymorphisms in type 2 diabetes and their functional defects.

We have previously identified PAX4 mutations causing MODY9 and a recent genome-wide association study reported a susceptibility locus of type 2 diabetes (T2D) near PAX4. In this study, we aim to investigate the association between PAX4 polymorphisms and T2D in Thai patients and examine functions of PAX4 variant proteins. PAX4 rs2233580 (R192H) and rs712701 (P321H) were genotyped in 746 patients with T2D and 562 healthy normal control subjects by PCR and restriction-fragment length polymorphism method. PAX4 variant proteins were investigated for repressor function on human insulin and glucagon promoters and for cell viability and apoptosis upon high glucose exposure. Genotype and allele frequencies of PAX4 rs2233580 were more frequent in patients with T2D than in control subjects (P=0.001 and 0.0006, respectively) with odds ratio of 1.66 (P=0.001; 95% confidence interval, 1.22-2.27). PAX4 rs712701 was not associated with T2D but it was in linkage disequilibrium with rs2233580. The 192H/321H (A/A) haplotype was more frequent in T2D patients than in controls (9.5% vs 6.6%; P=0.009). PAX4 R192H, but not PAX4 P321H, impaired repression activities on insulin and glucagon promoters and decreased transcript levels of genes required to maintain ß-cell function, proliferation and survival. Viability of ß-cell was reduced under glucotoxic stress condition for the cells overexpressing either PAX4 R192H or PAX4 P321H or both. Thus these PAX4 polymorphisms may increase T2D risk by defective transcription regulation of target genes and/or decreased ß-cell survival in high glucose condition.

DIFFERENCES IN MORTALITY BY EDUCATION LEVEL AMONG PATIENTS IN DIABETIC REGISTRY FOR THAILAND.

This study was conducted in order to determine the impact of education on mortality due cardiovascular, infectious and renal disease, and cancer among Thai diabetics using data from the Thailand diabetes registry cohort prospected and conducted between April 2003 and February 2006. The study population consisted of 9,370 registered diabetic patients attending ten diabetes clinics at tertiary medical centers in Bangkok and major provinces. The population was classified by education level: those who had not yet attained a bachelor's degree classified as having "lower education" (7,684: 82%) and those with a bachelor's degree or higher classified as having "higher education" (1,686:18%). The overall mortality rate among those in the higher education group was lower than those in the lower education group (8.9 vs 20.5 per 1,000 patient-years, respectively) with a hazard ratio (HR) of 0.43 (0.31-0.61). The higher education group also had lower mortality rates due to infectious disease [HR 0.10 (0.02-0.41)], renal disease [HR 0.24 (0.06-0.99)] and cardiovascular disease [HR 0.42 (0.22-0.80)]. There was no difference in cancer mortality between the two groups [HR 1.25 (0.74-2.11)].

The effects of transcription factor 7-like 2 rs7903146 and paired box 4 rs2233580 variants associated with type 2 diabetes on the therapeutic efficacy of hypoglycemic agents.

Aim: This study aims to investigate the effects of the TCF7L2 rs7903146 and PAX4 rs2233580 (R192H) variants associated with T2D on the therapeutic efficacies of various HAs in patients with T2D after follow-up for 3 years. Methods: A total of 526 patients who were followed up at the Diabetic Clinic of Siriraj Hospital during 2016-2019 were enrolled. The variants TCF7L2 rs7903146 and PAX4 rs2233580 (R192H) were genotyped using the RNase H2 enzyme-based amplification (rhAmp) technique and the associations between genotypes and glycemic control after treatments with different combinations HA were evaluated using Generalized Estimating Equations (GEE) analysis. Results: Patients who carried TCF7L2 rs7903146C/T + T/T genotypes when they were treated with biguanide alone had significantly lower fasting plasma glucose (FPG) than those of the patients who carried the C/C genotype (p = 0.01). Patients who carried the PAX4 rs2233580 G/G genotype when they were treated with sulfonylurea alone had significantly lower FPG than those of the patients who carried G/A + A/A genotypes (p = 0.04). Conclusion: Genotypes of TCF7L2 rs7903146 and PAX4 rs2233580 (R192H) variants associated with T2D influence the therapeutic responses to biguanide and sulfonylurea. Different genotypes of these two variants might distinctively affect the therapeutic effects of HAs. This finding provides evidence of pharmacogenetics in the treatment of diabetes.

Smoking and death in Thai diabetic patients: the Thailand Diabetic Registry cohort.

OBJECTIVE: To determine the impact of smoking and quit smoking on mortality rate. MATERIAL AND METHOD: This prospective cohort was a three-year follow-up of Thai Diabetes Registry project that registered 9,370 diabetic patients from 10 diabetic clinics in tertiary medical centers in Bangkok and major provinces between April 2003 and February 2006. RESULTS: The groups of 7,487 (80%), 1,315 (14%), and 568 (6%) patients were classified as non-smokers, ex-smokers, and current smokers. The crude death rate of ex-smokers (Hazard Ratio (HR) 1.52 (95% CI 1.19-1.95)) and current smokers (HR 1.55 (1.10-2.19)) were higher than death rate of non-smokers. After control for covariates, the HR comparing ex-smokers with non-smokers was not different (1.10 (0.81-1.50)), while the HR comparing current smokers with non-smokers remained statistical significant (1.74 (1.17-2.61)). CONCLUSION: Smoking increases mortality rate in diabetic patients by about 74%. Quitting smoking decreased mortality rate to the same rate as of diabetic non-smokers.

Generation of an induced pluripotent stem cell line (MUSIi015-A) from a diabetic patient carrying mutations in ZYG11A (p.L475P) and GATA6 (p.E51K).

Two heterozygous mutations (p.L475P in ZYG11A and p.E51K in GATA6) were identified in a family with autosomal dominant diabetes. ZYG11A-p.L475P was proposed as a causative mutation because of the complete segregation with hyperglycemia and the proven pathogenic effect on beta-cell expansion. The modifying effect of GATA6-p.E51K was proposed owing to the earlier onset of the carriers. Herein, we establish a line of induced pluripotent stem cells (iPSCs) from peripheral blood mononuclear cells (PBMCs) of a proband who carries both mutations using Sendai viral vectors. The generated iPSC line was characterized for pluripotency, chromosomal normality, and authentication.

Prevalence and Characteristics of Prediabetes and Metabolic Syndrome in Seemingly Healthy Persons at a Health Check-Up Clinic.

Purpose: This study investigated the prevalence and characteristics of prediabetes (PreDM) and metabolic syndrome (MetS) in seemingly healthy persons attending a health check-up clinic at a tertiary care hospital. Patients and Methods: This was a cross-sectional study that enrolled 1213 subjects (339 male, 874 female) who underwent an annual health check-up at Siriraj Hospital, Bangkok, Thailand from 2009 to 2019. Factors that independently related to PreDM were analyzed using unconditional logistic regression analysis with adjustments for age, BMI, and gender. Results: The prevalence of PreDM and MetS was 54.3% and 19.7% respectively. Participants with impaired fasting glucose (IFG) and glycated hemoglobin (HbA1c) 38.8-46.4 mmol/mol had significantly higher waist circumference (WC) and blood pressure (BP) compared to those with IFG or HbA1c 38.8-46.4 mmol/mol alone (P < 0.05). Among three PreDM subgroups, the average age was lowest in the HbA1c 38.8-46.4 mmol/mol subgroup (P < 0.001). PreDM participants with MetS were older (p = 0.03), had higher WC, BP, fasting plasma glucose and serum triglyceride level (all P < 0.001) but had lower serum high-density lipoprotein (HDL) cholesterol level (P < 0.001). Multivariate analysis revealed high MetS score, obesity, and low serum HDL cholesterol level to be independently associated with PreDM with odds ratios of 9.02 (95% confidence interval [CI]: 4.03-20.18), 1.8 (95% CI: 1.07-3.04), and 1.42 (95% CI: 1.02-1.96), respectively. Conclusion: The prevalence of PreDM and MetS was relatively high in seemingly healthy persons. Distinct PreDM subgroups with or without MetS exhibited diverse clinical and biochemical features suggesting dissimilar pathogenesis.

Clinical Characteristics, Glycemic Control, and Microvascular Complications Compared Between Young-Onset Type 1 and Type 2 Diabetes Patients at Siriraj Hospital - A Tertiary Referral Center.

Purpose: This study aimed to investigate the clinical characteristics, glycemic control, and microvascular complications compared between young-onset type 1 (T1DM) and type 2 diabetes (T2DM) patients at Siriraj Hospital. Patients and Methods: We collected demographic, clinical, glycemic control, and microvascular complication data of young-onset (onset <30 years of age) T1DM and T2DM patients at our center using February 2019-December 2020 data from the Thai Type 1 Diabetes and Diabetes diagnosed Age before 30 years Registry, Care and Network (T1DDAR CN). Results: Of 396 patients, 76% had T1DM and 24% had T2DM. At diagnosis, T1DM were significantly younger (9.7±5.4 vs 16.9±6.4 years, p<0.001), had a lower body mass index (17.2±4.1 vs 30.8±7.9 kg/m2, p<0.001), higher prevalence of diabetic ketoacidosis (DKA) (66.1% vs 13.7%, p<0.001), and higher HbA1c level (12.8±2.6% vs 10.9±3.1%, p=0.002) compared to T2DM. Regarding glycemic control, the mean HbA1c at registry enrollment did not differ between groups (T1DM 8.3±1.8% vs T2DM 8.1±2.2%, p=0.303), but T1DM achieved HbA1c <7% significantly less than T2DM (19.3% vs 47.8%, p<0.001). T1DM showed deterioration of glycemic control during 10-20 years of age, and gradually improved during 20-30 years of age, whereas patients with T2DM showed progressive worsening of glycemic control over time. Concerning microvascular complications, the prevalence of diabetic retinopathy (10.6% vs 9%, p=0.92) and diabetic neuropathy (3.4% vs 5.5%, p=0.514) between T1DM and T2DM was not significantly different. However, T2DM had a significantly higher prevalence of diabetic nephropathy (T1DM 10.1% vs T2DM 40.2%, p<0.001) that developed within a significantly shorter duration of diabetes (T1DM 11.0±6.8 vs T2DM 4.3±5.1 years, p<0.001) compared to T1DM. Conclusion: T1DM had a significantly high prevalence of DKA at presentation, and most T1DM did not achieve the glycemic target, especially during adolescence. T2DM had a significantly higher prevalence of diabetic nephropathy that developed within a shorter duration of diabetes compared to T1DM.

Generation of an induced pluripotent stem cell line (MUSIi014-A) from an affected member of a family with autosomal dominant diabetes carrying p.L475P mutation in ZYG11A gene associated with a cell cycle arrest in beta-cell.

A heterozygous mutation (c.T1424C: p.L475P) in ZYG11A completely segregating with hyperglycemia in a Thai family with familial diabetes of the adulthood has been reported as a cause of cell cycle arrest in 1.1B4 cell line. This mutation is a suggestive cause of failure in adaptive beta-cell expansion which, thereby, contributes to the development of diabetes in the family. Here, an induced pluripotent stem cell (iPSC) line from peripheral blood mononuclear cells (PBMCs) of an affected family member carrying the mutation was generated using Sendai viral reprogramming. The established iPSC line is characterized and confirmed for pluripotency and chromosomal integrity.

Cluster analysis of Thai patients with newly diagnosed type 2 diabetes mellitus to predict disease progression and treatment outcomes : A prospective cohort study.

INTRODUCTION: Type 2 diabetes mellitus (T2D) is highly heterogeneous in disease progression and risk of complications. This study aimed to categorize Thai T2D into subgroups using variables that are commonly available based on routine clinical parameters to predict disease progression and treatment outcomes. RESEARCH DESIGN AND METHODS: This was a cohort study. Data-driven cluster analysis was performed using a Python program in patients with newly diagnosed T2D (n=721) of the Siriraj Diabetes Registry using five variables (age, body mass index (BMI), glycated hemoglobin (HbA1c), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C)). Disease progression and risk of diabetic complications among clusters were compared using the Χ2 and Kruskal-Wallis test. Cox regression and the Kaplan-Meier curve were used to compare the time to diabetic complications and the time to insulin initiation. RESULTS: The mean age was 53.4±11.3 years, 58.9% were women. The median follow-up time was 21.1 months (9.2-35.2). Four clusters were identified: cluster 1 (18.6%): high HbA1c, low BMI (insulin-deficiency diabetes); cluster 2 (11.8%): high TG, low HDL-C, average age and BMI (metabolic syndrome group); cluster 3 (23.3%): high BMI, low HbA1c, young age (obesity-related diabetes); cluster 4 (46.3%): older age and low HbA1c at diagnosis (age-related diabetes). Patients in cluster 1 had the highest prevalence of insulin treatment. Patients in cluster 2 had the highest risk of diabetic kidney disease and diabetic retinopathy. Patients in cluster 4 had the lowest prevalence of diabetic retinopathy, nephropathy, and insulin use. CONCLUSIONS: We were able to categorize Thai patients with newly diagnosed T2D into four clusters using five routine clinical parameters. This clustering method can help predict disease progression and risk of diabetic complications similar to previous studies using parameters including insulin resistance and insulin sensitivity markers.

Autosomal dominant diabetes associated with a novel ZYG11A mutation resulting in cell cycle arrest in beta-cells.

Diabetes is a genetically heterogeneous disease, for which we are aiming to identify causative genes. Here, we report a missense mutation (c.T1424C:p.L475P) in ZYG11A identified by exome sequencing as segregating with hyperglycemia in a Thai family with autosomal dominant diabetes. ZYG11A functions as a target recruitment subunit of an E3 ubiquitin ligase complex that plays an important role in the regulation of cell cycle. We demonstrate an increase in cells arrested at G2/mitotic phase among beta-cells deficient for ZYG11A or overexpressing L475P-ZYG11A, which is associated with a decreased growth rate. This is the first evidence linking a ZYG11A mutation to hyperglycemia, and suggesting ZYG11A as a cell cycle regulator required for beta-cell growth. Since most family members were either overweight or obese, but only mutation carriers developed hyperglycemia, our data also suggests the ZYG11A mutation as a genetic factor predisposing obese individuals to beta-cell failure in maintenance of glucose homeostasis.

Thailand Diabetic Registry cohort: predicting death in Thai diabetic patients and causes of death.

INTRODUCTION: The prevalence of type 2 diabetes in Thailand is 9.8 percent which is double the number forecast by World Health Organization. There is inadequate information to statistically represent all Thai diabetic patients for their causes of death. OBJECTIVE: To determine the clinical characteristics that predicted death and causes of death in Thai diabetic patients. MATERIAL AND METHOD: This prospective cohort was a 3-year follow-up study of the Thai Diabetes Registry project done between April, 2003, and February, 2006, which registered 9,419 diabetic patients attending 11 diabetic clinics in tertiary medical centers in Bangkok and major provinces of Thailand. The dead or alive status (99.5%) was determined. The causes of death were defined by reviewing the medical records. RESULTS: Of the 9,370 diabetic patients registered, 425 patients died, 1.84 percent per year. There was an increased risk of death associated with age, type of healthcare plan, lower education, insulin use, smoking, history of coronary artery disease and cerebrovascular disease, serum creatinine and high HbA1c. Lipid-lowering medication and metformin decreased the risk of death. Cardiovascular disease, infection and cancer were the prevalent causes of death. CONCLUSION: The present study showed risk factors that influenced death and causes of death in Thai diabetics.

Effect of Preoperative Vitamin D Deficiency on Hypocalcemia in Patients with Acute Hypoparathyroidism after Thyroidectomy.

Postoperative hypoparathyroidism is a common complication of total or completion thyroidectomy. The association between preoperative vitamin D deficiency (VDD) and the development of more severe postoperative hypocalcemia is still unclear. Objectives. To evaluate the effect of preoperative VDD on severity of hypocalcemia in patients with hypoparathyroidism following thyroidectomy. Methods. Patients who developed acute hypoparathyroidism after total or completion thyroidectomy, defined as postoperative parathyroid hormone (PTH) level <15 pg/mL and albumin-adjusted calcium level <8.6 mg/dL, were prospectively recruited. Patients were divided into two groups according to their preoperative vitamin D status (VDD group: 25-hydroxyvitamin D (25(OH)D) level <20 ng/mL; non-VDD group: 25(OH) level ≥20 ng/mL). The primary outcome was severity of hypocalcemia in postoperative hypoparathyroidism. Significant hypocalcemia was defined as calcium level ≤7.5 mg/dL. Results. Forty-three patients (21 VDD, 22 non-VDD) were enrolled. Serum total albumin-adjusted calcium level was significantly lower in the VDD group (7.71 ± 0.5 vs. 8.16 ± 0.4 mg/dL, p < 0.01), and the incidence of symptomatic hypocalcemia was significantly higher in the VDD group (43% vs. 9%, p=0.01). The median maximal daily supplementary dose of elemental calcium was significantly higher in the VDD group (2,400 vs. 1,500 mg/day, p=0.02). Length of hospital stay was nonsignificantly longer in the VDD group (p=0.06). Preoperative vitamin D level <19.6 ng/mL could predict significant and symptomatic hypocalcemia in postoperative hypoparathyroidism with sensitivity of 90% and 82% and specificity of 70% and 69%, respectively. Conclusion. VDD is an independent risk factor for both significant and symptomatic hypocalcemia in hypoparathyroidism patients after thyroid surgery.

Functional defect of truncated hepatocyte nuclear factor-1alpha (G554fsX556) associated with maturity-onset diabetes of the young.

A novel frameshift mutation attributable to 14-nucleotide insertion in hepatocyte nuclear factor-1alpha (HNF-1alpha) encoding a truncated HNF-1alpha (G554fsX556) with 76-amino acid deletion at its carboxyl terminus was identified in a Thai family with maturity-onset diabetes of the young (MODY). The wild-type and mutant HNF-1alpha proteins were expressed by in vitro transcription and translation (TNT) assay and by transfection in HeLa cells. The wild-type and mutant HNF-1alpha could similarly bind to human glucose-transporter 2 (GLUT2) promoter examined by electrophoretic mobility shift assay (EMSA). However, the transactivation activities of mutant HNF-1alpha on human GLUT2 and rat L-type pyruvate kinase (L-PK) promoters in HeLa cells determined by luciferase reporter assay were reduced to approximately 55-60% of the wild-type protein. These results suggested that the functional defect of novel truncated HNF-1alpha (G554fsX556) on the transactivation of its target-gene promoters would account for the beta-cell dysfunction associated with the pathogenesis of MODY.

Mutations of maturity-onset diabetes of the young (MODY) genes in Thais with early-onset type 2 diabetes mellitus.

OBJECTIVE: Six known genes responsible for maturity-onset diabetes of the young (MODY) were analysed to evaluate the prevalence of their mutations in Thai patients with MODY and early-onset type 2 diabetes. PATIENTS AND METHODS: Fifty-one unrelated probands with early-onset type 2 diabetes, 21 of them fitted into classic MODY criteria, were analysed for nucleotide variations in promoters, exons, and exon-intron boundaries of six known MODY genes, including HNF-4alpha, GCK, HNF-1alpha, IPF-1, HNF-1beta, and NeuroD1/beta2, by the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method followed by direct DNA sequencing. Missense mutations or mutations located in regulatory region, which were absent in 130 chromosomes of non-diabetic controls, were classified as potentially pathogenic mutations. RESULTS: We found that mutations of the six known MODY genes account for a small proportion of classic MODY (19%) and early-onset type 2 diabetes (10%) in Thais. Five of these mutations are novel including GCK R327H, HNF-1alpha P475L, HNF-1alphaG554fsX556, NeuroD1-1972 G > A and NeuroD1 A322N. Mutations of IPF-1 and HNF-1beta were not identified in the studied probands. CONCLUSIONS: Mutations of the six known MODY genes may not be a major cause of MODY and early-onset type 2 diabetes in Thais. Therefore, unidentified genes await discovery in a majority of Thai patients with MODY and early-onset type 2 diabetes.

HNF1A mutation in a Thai patient with maturity-onset diabetes of the young: A case report.

BACKGROUND: Maturity-onset diabetes of the young (MODY) is the most common form of monogenic diabetes. The disease is transmitted in autosomal dominant mode and diabetes is usually diagnosed before age 25 year. MODY 3 is caused by mutation of hepatocyte nuclear factor (HNF) 1A genes and is the most common MODY subtype. Diagnosis of MODY 3 is crucial since glycemic control can be accomplished by very low dose of sulfonylurea. In this report we described a Thai MODY 3 patient who had excellence plasma glucose control by treating with glicazide 20 mg per day and insulin therapy can be discontinued. CASE SUMMARY: A 31-year-old woman was diagnosed diabetes mellitus at 14 years old. The disease was transmitted from her grandmother and mother compatible with autosomal dominant inheritance. Sanger sequencing of proband's DNA identified mutation of HNF1A at codon 203 which changed amino acid from arginine to cysteine (R203C). This mutation was carried only by family members who have diabetes. The patient has been treated effectively with a combination of oral hypoglycemic agents and must include a very low dose of glicazide (20 mg/d). Insulin therapy was successfully discontinued. CONCLUSION: We demonstrated a first case of pharmacogenetics in Thai MODY 3 patient. Our findings underscore the essential role of molecular genetics in diagnosis and guidance of appropriate treatment of diabetes mellitus in particular patient.

Fanconi anemia complementation group C protection against oxidative stress­induced ß­cell apoptosis.

Diabetes mellitus (DM) and other glucose metabolism abnormalities are commonly observed in individuals with Fanconi anemia (FA). FA causes an impaired response to DNA damage due to genetic defects in a cluster of genes encoded proteins involved in DNA repair. However, the mechanism by which FA is associated with DM has not been clearly elucidated. Fanconi anemia complementation group C (FANCC) is a component of FA nuclear clusters. Evidence suggests that cytoplasmic FANCC has a role in protection against oxidative stress­induced apoptosis. As oxidative stress­mediated ß­cell dysfunction is one of the contributors to DM pathogenesis, the present study aimed to investigate the role of FANCC in pancreatic ß­cell response to oxidative stress. Small interfering RNA­mediated FANCC suppression caused a loss of protection against oxidative stress­induced apoptosis, and that overexpression of FANCC reduced this effect in the human 1.1B4 ß­cell line. These findings were confirmed by Annexin V­FITC/PI staining, caspase 3/7 activity assay, and expression levels of anti­apoptotic and pro­apoptotic genes. Insulin and glucokinase mRNA expression were also decreased in FANCC­depleted 1.1B4 cells. The present study demonstrated the role of FANCC in protection against oxidative stress­induced ß­cell apoptosis and established another mechanism that associates FANCC deficiency with ß­cell dysfunction. The finding that FANCC overexpression reduced ß­cell apoptosis advances the potential for an alternative approach to the treatment of DM caused by FANCC defects.

DNAJC3 mutation in Thai familial type 2 diabetes mellitus.

Type 2 diabetes mellitus (T2D) is a heterogeneous disease, with certain cases presenting an autosomal dominant type. The rare coding variants of disease­causing genes in T2D remain mostly unclear. The present study aimed to identify the disease­causing gene conducting whole exome sequencing in a Thai T2D family with an autosomal dominant transmission of T2D with no evidence of mutations in known maturity­onset diabetes of the young (MODY) genes. Candidate variants were selected according to certain criteria of mutation prediction programs, followed by segregation analysis with diabetes in the family. The results demonstrated that, of the 68,817 variants obtained, 122 were considered as candidate variants subsequent to the filtering processes. Genotyping of these variants revealed that DnaJ homolog subfamily C member 3 (DNAJC3) p.H238N segregated with diabetes in the family. This mutation was also identified in another proband from the autosomal dominant T2D family without mutation in known MODY genes and was segregated with diabetes. This variant was also identified in 14/1,000 older­onset T2D patients [minor allele frequency (MAF)=0.007], 2/500 non­diabetic controls (MAF=0.002) and 3 prediabetic individuals who were previously classified as non­diabetic controls. In silico mutagenesis and protein modeling of p.H238N revealed changes of the polar contacts across the tetratricopeptide repeat (TPR) motif and TPR subdomains, which may affect the protein tertiary structure. Furthermore, the expression of DNAJC3 H238N protein was 0.68±0.08 fold (P<0.05) lower when compared with that of the wild­type, possibly due to protein instability. Thus, DNAJC3 p.H238N is likely to be a variant causing diabetes.