Familial early-onset type 2 diabetes in Chinese patients: obesity and genetics have more significant roles than autoimmunity

The rising prevalence of type 2 diabetes among the youth in southern India-An ancillary analysis of the Secular TRends in DiabEtes in India (STRiDE-I) study

BACKGROUND

We studied the prevalence and incidence of type 2 diabetes (T2DM) and its associated risk factors in younger (20 and 39 years) and older individuals (≥40 years) over a 10-year period.

METHODS

Epidemiological surveys in 2006 (n = 7066) and 2016 (n = 9848) were conducted in similar urban and rural locations of southern India among people aged ≥20 years. Diagnosis of T2DM was made using World Health Organization criteria. Self-reported diabetes was verified from medical records. Age and gender standardized prevalence and incidence rates, percentage change in obesity, hypertension, and dyslipidemia were calculated. Prevalence ratios (PR) were calculated using Poisson regression analyses. Primary study was registered on www.

CLINICALTRIALS

gov. Identifier: NCT03490136.

RESULTS

In 10 years, the prevalence of T2DM increased in younger (7.8% vs. 4.5%, p < 0.0001) and older individuals (34% vs. 28.4%, p < 0.0001). After adjusting for age, family history of diabetes, and waist circumference, younger individuals showed a higher percentage increase in prevalence than the older group (PR = 1.36 [95% confidence interval [CI], 1.14-1.62], p = 0.001) versus (PR = 1.11 [95% CI, 1.02-1.20], p = 0.02). Increase in rates of obesity and dyslipidemia was also higher in the younger than in the older individuals. In 10 years, incidence of T2DM increased by 120% (1.1% vs. 0.5%, p < 0.0001) and 150% (5% vs. 2%, p < 0.0001) in the younger and older individuals, respectively.

CONCLUSIONS

Higher percentage increase in prevalence of T2DM was seen among younger individuals over a 10-year period. Obesity and family history of diabetes were shown to be the primary contributing factors for the rise in prevalence.

Impact of the trans-ancestry polygenic risk score on type 2 diabetes risk, onset age and progression among population in Taiwan

Type 2 diabetes (T2D) prevalence in adults at a younger age has increased but the disease status may go unnoticed. This study aimed to determine whether the onset age and subsequent diabetic complications can be attributed to the polygenic architecture of T2D in the Taiwan Han population. A total of 9,627 cases with T2D and 85,606 controls from the Taiwan Biobank were enrolled. Three diabetic polygenic risk scores (PRSs), PRS_EAS and PRS_EUR, and a trans-ancestry PRS (PRS_META), calculated using summary statistic from East Asian and European populations. The onset age was identified by linking to the National Taiwan Insurance Research Database, and the incidence of different diabetic complications during follow-up was recorded. PRS_META (7.4%) explained a higher variation for T2D status. And the higher percentile of PRS is also correlated with higher percentage of T2D family history and prediabetes status. More, the PRS was negatively associated with onset age (β = -0.91 yr), and this was more evident among males (β = -1.11 vs. -0.76 for males and females, respectively). The hazard ratio of diabetic retinopathy (DR) and diabetic foot were significantly associated with PRS_EAS and PRS_META, respectively. However, the PRS was not associated with other diabetic complications, including diabetic nephropathy, cardiovascular disease, and hypertension. Our findings indicated that diabetic PRS which combined susceptibility variants from cross-population could be used as a tool for early screening of T2D, especially for high-risk populations, such as individuals with high genetic risk, and may be associated with the risk of complications in subjects with T2D. NEW & NOTEWORTHY Our findings indicated that diabetic polygenic risk score (PRS) which combined susceptibility variants from Asian and European population affect the onset age of type 2 diabetes (T2D) and could be used as a tool for early screening of T2D, especially for individuals with high genetic risk, and may be associated with the risk of diabetic complications among people in Taiwan.

Combined associations of family history and self-management with age at diagnosis and cardiometabolic risk in 86,931 patients with type 2 diabetes: Joint Asia Diabetes Evaluation (JADE) Register from 11 countries

BACKGROUND

Family history (FamH) of type 2 diabetes might indicate shared genotypes, environments, and/or behaviors. We hypothesize that FamH interacts with unhealthy behaviors to increase the risk of early onset of diabetes and poor cardiometabolic control.

METHODS

In a cross-sectional analysis of the prospective Joint Asia Diabetes Evaluation Register including patients from 427 clinics in 11 Asian countries/regions in 2007-2021, we defined positive FamH as affected parents/siblings and self-management as (1) healthy lifestyles (balanced diet, non-use of alcohol and tobacco, regular physical activity) and (2) regular self-monitoring of blood glucose (SMBG).

RESULTS

Among 86,931 patients with type 2 diabetes (mean±SD age: 56.6±11.6 years; age at diagnosis of diabetes: 49.8±10.5 years), the prevalence of FamH ranged from 39.1% to 85.3% in different areas with FamH affecting mother being most common (32.5%). The FamH group (n=51,705; 59.5%) was diagnosed 4.6 years earlier than the non-FamH group [mean (95% CI): 47.9 (47.8-48.0) vs. 52.5 (52.4-52.6), logrank p<0.001]. In the FamH group, patients with both parents affected had the earliest age at diagnosis [44.6 (44.5-44.8)], followed by affected single parent [47.7 (47.6-47.8)] and affected siblings only [51.5 (51.3-51.7), logrank p<0.001]. The FamH plus ≥2 healthy lifestyle group had similar age at diagnosis [48.2 (48.1-48.3)] as the non-FamH plus <2 healthy lifestyle group [50.1 (49.8-50.5)]. The FamH group with affected parents had higher odds of hyperglycemia, hypertension, and dyslipidemia than the FamH group with affected siblings, with the lowest odds in the non-FamH group. Self-management (healthy lifestyles plus SMBG) was associated with higher odds of attaining HbA_1c<7%, blood pressure<130/80mmHg, and LDL-C<2.6 mmol/L especially in the FamH group (FamH×self-management, p_interaction=0.050-0.001).

CONCLUSIONS

In Asia, FamH was common and associated with young age of diagnosis which might be delayed by healthy lifestyle while self management  was associated with better control of  cardiometabolic risk factors especially in those with FamH.

Early-onset of type 2 diabetes mellitus is a risk factor for diabetic nephropathy progression: a biopsy-based study

Several studies show that patients with early-onset diabetes have higher risk of diabetic complications than those diagnosed in middle age. However, whether early-onset of type 2 diabetes mellitus (T2DM) is a risk factor for diabetic nephropathy (DN) progression remains unclear, especially a lack of data in biopsy-confirmed cohort. In This study, we enrolled 257 patients with T2DM and biopsy-confirmed DN to investigate the role of early-onset T2DM in DN progression. Participants were divided into two groups according to the age of T2DM diagnosis: early-onset group (less than 40 years) and later-onset group (40 years or older). We found that patients with early-onset T2DM had higher glomerular grades and arteriolar hyalinosis scores than those in later-onset group. After adjusted for confounding factors, early-onset of T2DM remained an independent predictor of end-stage renal disease (ESRD) for patients with DN. In conclusion, although with the comparable renal function and proteinuria, patients with early-onset T2DM and DN had worse renal pathological changes than those with later-onset. Early-onset of T2DM might be an important predictor of ESRD for patients with DN, which called more attention to early supervision and prevention for patients with early-onset T2DM and DN.

Long-term outcomes of ischaemic stroke patients with diabetes in a multi-ethnic cohort in Singapore

ABSTRACT Introduction: Diabetes increases the risk of ischaemic stroke especially among Asians. This study aims to investigate contemporaneous long-term cardiovascular outcomes of ischaemic stroke patients with diabetes in a multi-ethnic Asian cohort. Methods: Consecutive patients with ischaemic stroke were recruited from the National University Hospital, Singapore. Data on age, gender, ethnicity, risk factors (including diabetes status and body mass index [BMI]), stroke severity and mechanisms were collected. These patients were followed up until the day of the first cardiovascular event or July 2016, whichever was earlier. The primary endpoint was the time from enrolment to the first occurrence of a composite of cerebrovascular and coronary artery events. Results: Between July 2011 and December 2013, 720 patients (mean age 60.6 years, 71% men, 43% with diabetes, median National Institute Health Stroke Severity scale 2) were enrolled and followed up. A total of 175 cardiovascular events occurred during a median follow-up of 3.25 years (6.90 events per 1,000 person-month), comprising 163 cerebrovascular and 42 coronary artery events. The adjusted hazard ratio of diabetes was 1.50 (95% CI 1.08–2.10). In a multivariable Cox proportional hazards model, Malay and Indian ethnicities, BMI <23kg/m2 and a prior diagnosis of diabetes were identified as independent predictors of recurrent cardiovascular events. Conclusion: Our study provides quantitative data on the event rates of ischaemic stroke patients with diabetes. These findings provide insights on stroke predictors in a multi-ethnic Asian population, which may have implications in the design of future interventional studies. Keywords: Asian, body mass index, cardiovascular, stroke phenotype

Identification of Novel GCK and HNF4α Gene Variants in Japanese Pediatric Patients with Onset of Diabetes before 17 Years of Age

BACKGROUND

Maturity-onset diabetes of the young (MODY) is commonly misdiagnosed as type 1 or type 2 diabetes. Common reasons for misdiagnosis are related to limitations in genetic testing. A precise molecular diagnosis is essential for the optimal treatment of patients and allows for early diagnosis of their asymptomatic family members.

OBJECTIVE

The aim of this study was to identify rare monogenic variants of common MODY genes in Japanese pediatric patients.

METHODS

We investigated 45 Japanese pediatric patients based on the following clinical criteria: development of diabetes before 17 years of age, a family history of diabetes, testing negative for glutamate decarboxylase-65 (GAD 65) antibodies and insulinoma-2-associated autoantibodies (IA-2A), no significant obesity, and evidence of endogenous insulin production. Genetic screening for MODY1 (HNF4α), MODY2 (GCK), MODY3 (HNF1α), and MODY5 (HNF1β) was performed by direct sequencing followed by multiplex ligation amplification assays.

RESULTS

We identified 22 missense variants (3 novel variants) in 27 patients (60.0%) in the GCK, HNF4α, and HNF1α genes. We also detected a whole exon deletion in the HNF1β gene and an exon 5-6 aberration in the GCK gene, each in one proband (4.4%). There were a total of 29 variations (64.4%), giving a relative frequency of 53.3% (24/45) for GCK, 2.2% (1/45) for HNF4α, 6.7% (3/45) for HNF1α, and 2.2% (1/45) for HNF1β genes.

CONCLUSIONS

Clinicians should consider collecting and assessing detailed clinical information, especially regarding GCK gene variants, in young antibody-negative patients with diabetes. Correct molecular diagnosis of MODY better predicts the clinical course of diabetes and facilitates individualized management.

Phenotypic and Genetic Heterogeneity in a Thai Glucokinase MODY Family Reveals the Complexity of Young-Onset Diabetes

Glucokinase-Maturity-Onset Diabetes of the Young (GCK-MODY) is characterized by asymptomatic, non-progressive and fasting hyperglycemia, albeit not without phenotypic variability. We used next generation sequencing (NGS) to screen for 34 MODY genes in a non-obese person with familial young-onset diabetes followed by screening in 24 family members within three generations with varying presentations of young-onset diabetes and sensorineural hearing loss. The index patient was found to carry a paternally-inherited heterozygous missense variant (c.716 A>G) of GCK in exon 7 with amino acid change (Q239R). This variant was associated with phenotypic heterogeneity ranging from normal glucose tolerance to diabetes with complications amongst the siblings which might be modified by obesity and chronic hepatitis B infection. Two paternally-inherited variants of SLC29A3 encoding a nucleoside transporter protein and Apo-A1 genes also co-segregated with glucose and lipid traits. Co-occurrence of diabetes and deafness in maternal aunts led to discovery of WFS1 (Wolfram syndrome type 1) as a cause of non-syndromic deafness in multiple members of the maternal pedigree. Our findings highlight the complex causes of familial young-onset diabetes and the need of a multidisciplinary approach to interpret the clinical relevance of discoveries made by NGS in this era of genomic medicine.

Functional Characterization of a Novel Heterozygous Mutation in the Glucokinase Gene That Causes MODY2 in Chinese Pedigrees

BACKGROUND

Glucokinase (GCK) plays a central role in glucose regulation. The heterozygous mutations of GCK can cause a monogenic form of diabetes, maturity-onset diabetes of the young (MODY) directly. In our study, we aimed to explore the mechanism of the novel mutation GCK p.Ala259Thr leading to glucokinase deficiency and hyperglycemia.

METHODS

Thirty early-onset diabetes pedigrees were referred to whole exome sequencing for novel mutations identification. Purified wild-type and mutant GCK proteins were obtained from E.coli systems and then subjected to the kinetic and thermal stability analysis to test the effects on GCK activity.

RESULTS

One novel missense mutation GCK p.Ala259Thr was identified and co-segregated with diabetes in a Chinese MODY2 pedigree. The kinetic analysis showed that this mutation result in a decreased affinity and catalytic capability for glucose. The thermal stability analysis also indicated that the mutant protein presented dramatically decreased activity at the same temperature.

CONCLUSION

Our study firstly identified a novel MODY2 mutation p.Ala259Thr in Chinese diabetes pedigrees. The kinetic and thermal stability analysis confirmed that this mutation caused hyperglycemia through severely damaging the enzyme activities and protein stability.

Age at diagnosis, glycemic trajectories, and responses to oral glucose-lowering drugs in type 2 diabetes in Hong Kong: A population-based observational study

BACKGROUND

Lifetime glycemic exposure and its relationship with age at diagnosis in type 2 diabetes (T2D) are unknown. Pharmacologic glycemic management strategies for young-onset T2D (age at diagnosis <40 years) are poorly defined. We studied how age at diagnosis affects glycemic exposure, glycemic deterioration, and responses to oral glucose-lowering drugs (OGLDs).

METHODS AND FINDINGS

In a population-based cohort (n = 328,199; 47.2% women; mean age 34.6 and 59.3 years, respectively, for young-onset and usual-onset [age at diagnosis ≥40 years] T2D; 2002-2016), we used linear mixed-effects models to estimate the association between age at diagnosis and A1C slope (glycemic deterioration) and tested for an interaction between age at diagnosis and responses to various combinations of OGLDs during the first decade after diagnosis. In a register-based cohort (n = 21,016; 47.1% women; mean age 43.8 and 58.9 years, respectively, for young- and usual-onset T2D; 2000-2015), we estimated the glycemic exposure from diagnosis until age 75 years. People with young-onset T2D had a higher mean A1C (8.0% [standard deviation 0.15%]) versus usual-onset T2D (7.6% [0.03%]) throughout the life span (p < 0.001). The cumulative glycemic exposure was >3 times higher for young-onset versus usual-onset T2D (41.0 [95% confidence interval 39.1-42.8] versus 12.1 [11.8-12.3] A1C-years [1 A1C-year = 1 year with 8% average A1C]). Younger age at diagnosis was associated with faster glycemic deterioration (A1C slope over time +0.08% [0.078-0.084%] per year for age at diagnosis 20 years versus +0.02% [0.016-0.018%] per year for age at diagnosis 50 years; p-value for interaction <0.001). Age at diagnosis ≥60 years was associated with glycemic improvement (-0.004% [-0.005 to -0.004%] and -0.02% [-0.027 to -0.0244%] per year for ages 60 and 70 years at diagnosis, respectively; p-value for interaction <0.001). Responses to OGLDs differed by age at diagnosis (p-value for interaction <0.001). Those with young-onset T2D had smaller A1C decrements for metformin-based combinations versus usual-onset T2D (metformin alone: young-onset -0.15% [-0.105 to -0.080%], usual-onset -0.17% [-0.179 to -0.169%]; metformin, sulfonylurea, and dipeptidyl peptidase-4 inhibitor: young-onset -0.44% [-0.476 to -0.405%], usual-onset -0.48% [-0.498 to -0.459%]; metformin and α-glucosidase inhibitor: young-onset -0.40% [-0.660 to -0.144%], usual-onset -0.25% [-0.420 to -0.077%]) but greater responses to other combinations containing sulfonylureas (sulfonylurea alone: young-onset -0.08% [-0.099 to -0.065%], usual-onset +0.06% [+0.059 to +0.072%]; sulfonylurea and α-glucosidase inhibitor: young-onset -0.10% [-0.266 to 0.064%], usual-onset: 0.25% [+0.196% to +0.312%]). Limitations include possible residual confounding and unknown generalizability outside Hong Kong.

CONCLUSIONS

In this study, we observed excess glycemic exposure and rapid glycemic deterioration in young-onset T2D, indicating that improved treatment strategies are needed in this setting. The differential responses to OGLDs between young- and usual-onset T2D suggest that better disease classification could guide personalized therapy.

Predicting Mortality Due to SARS-CoV-2: A Mechanistic Score Relating Obesity and Diabetes to COVID-19 Outcomes in Mexico

BACKGROUND

The SARS-CoV-2 outbreak poses a challenge to health care systems due to its high complication rates in patients with cardiometabolic diseases. Here, we identify risk factors and propose a clinical score to predict COVID-19 lethality, including specific factors for diabetes and obesity, and its role in improving risk prediction.

METHODS

We obtained data of confirmed and negative COVID-19 cases and their demographic and health characteristics from the General Directorate of Epidemiology of the Mexican Ministry of Health. We investigated specific risk factors associated to COVID-19 positivity and mortality and explored the impact of diabetes and obesity on modifying COVID-19-related lethality. Finally, we built a clinical score to predict COVID-19 lethality.

RESULTS

Among the 177 133 subjects at the time of writing this report (May 18, 2020), we observed 51 633 subjects with SARS-CoV-2 and 5,332 deaths. Risk factors for lethality in COVID-19 include early-onset diabetes, obesity, chronic obstructive pulmonary disease, advanced age, hypertension, immunosuppression, and chronic kidney disease (CKD); we observed that obesity mediates 49.5% of the effect of diabetes on COVID-19 lethality. Early-onset diabetes conferred an increased risk of hospitalization and obesity conferred an increased risk for intensive care unit admission and intubation. Our predictive score for COVID-19 lethality included age ≥ 65 years, diabetes, early-onset diabetes, obesity, age < 40 years, CKD, hypertension, and immunosuppression and significantly discriminates lethal from non-lethal COVID-19 cases (C-statistic = 0.823).

CONCLUSIONS

Here, we propose a mechanistic approach to evaluate the risk for complications and lethality attributable to COVID-19, considering the effect of obesity and diabetes in Mexico. Our score offers a clinical tool for quick determination of high-risk susceptibility patients in a first-contact scenario.

Molecular diagnosis of maturity-onset diabetes of the young in a cohort of Chinese children

OBJECTIVE

The purpose of this study was to investigate the molecular basis of maturity-onset diabetes of the young (MODY) by whole-exome sequencing (WES) and estimate the frequency and describe the clinical characteristics of MODY in southern China.

METHODS

Genetic analysis was performed in 42 patients with MODY aged 1 month to 18 years among a cohort of 759 patients with diabetes, identified with the following four clinical criteria: age of diagnosis ≤18 years; negative pancreatic autoantibodies; family history of diabetes; or persistently detectable C-peptide; or diabetes associated with extrapancreatic features. GCK gene mutations were first screened by Sanger sequencing. GCK mutation-negative patients were further analyzed by WES.

RESULTS

Mutations were identified in 24 patients: 20 mutations in GCK, 1 in HNF4A, 1 in INS, 1 in ABCC8, and a 17q12 microdeletion. Four previously unpublished novel GCK mutations: c.1108G>C in exon 9, and c.1339C>T, c.1288_1290delCTG, and c.1340_1343delGGGGinsCTGGTCT in exon 10 were detected. WES identified a novel missense mutation c.311A>G in exon 3 in the INS gene, and copy number variation analysis detected a 1.4 Mb microdeletion in the long arm of the chromosome 17q12 region. Compared with mutation-negative subjects, the mutation-positive subjects had lower hemoglobin A1c and initial blood glucose levels.

CONCLUSIONS

Most MODY cases in this study were due to GCK mutations, which is in contrast to previous reports in Chinese patients. Diabetes associated with extrapancreatic features should be a clinical criterion for MODY genetic analysis. Mutational analysis by WES provided a precise diagnosis of MODY subtypes. Moreover, WES can be useful for detecting large deletions in coding regions in addition to point mutations.

Screening of HNF1A and HNF4A mutation and clinical phenotype analysis in a large cohort of Chinese patients with maturity-onset diabetes of the young

AIMS

The study aimed to screen the HNF1A and HNF4A mutation in a large Chinese cohort of high clinical suspicion of maturity-onset diabetes of the young (MODY) patients and characterize the clinical features of those patients. The performance of hsCRP as a biomarker to differentiate MODY3 from early onset T2DM was also evaluated.

METHODS

A total of 74 patients with a strong clinical suspicion of MODY from 59 families and 33 newly diagnosed early-onset T2DM were included. HNF1A and HNF4A mutations were analyzed by Sanger sequencing. ROC curves were used to identify the optimal cutoff of hsCRP.

RESULTS

One novel (c.864_865insG) and six recurrent HNF1A mutations (R203H, R263H, P379T, L422P, P519L and c.873delC) in 17 patients from 8 families (13.6%), as well as one novel HNF4A (R331H) mutation were identified. Nonspecific clinical presentations were observed in MODYX compared to MODY3 patients. MODY3 subjects exhibited with younger, lower BMI, TG, fasting and postprandial C-peptide, higher HDL than T2DM. Particularly, we confirmed serum hsCRP was lower in MODY3 than T2DM. ROC curve showed a good discrimination with an AUC of 0.852 and identified a cutoff hsCRP of 0.79 (75% sensitivity and 83% specificity). Good glycemic control was observed in all identified patients after switching to glimepiride therapy.

CONCLUSIONS

The prevalence of HNF1A mutation was relatively lower in Mainland China and HNF4A mutation was rare. Serum hsCRP concentrations performed well in discriminating MODY3 from T2DM. Molecular diagnosis of MODY3/1 did transform management in clinical practice and facilitated the glycemic control.

Insights into pathogenesis of five novel GCK mutations identified in Chinese MODY patients

OBJECTIVE

Heterozygous inactivating mutations in GCK are associated with defects in pancreatic insulin secretion and/or hepatic glycogen synthesis leading to mild chronic hyperglycaemia of maturity onset diabetes of young type 2 (MODY2). However, the effect of naturally occurring GCK mutations on the pathogenesis for MODY2 hyperglycaemia remains largely unclear, especially in the Asian population. The aim of this study is to explore the potential pathogenicity of novel GCK mutations related to MODY2.

METHODS

Genetic screening for GCK mutations from 96 classical MODY families was performed, and structure-function characterization and clinical profile of identified GCK mutations were conducted.

RESULTS

Five novel (F195S, I211T, V222D, E236G and K458R) and five known (T49N, I159V, R186X, A188T and M381T) mutations were identified and co-segregated with hyperglycaemia in their pedigrees. R186X generates non-functional truncated form and V222D and E236G fully inactivate glucokinase due to severe structure disruptions. The other seven GCK mutations exhibited marked reductions in catalytic efficiency and thermo-stability; notably, the interaction with GKRP was significantly enhanced in I211T, I159V, T49N and K458R, reduced in F195S and M381T, and completely lost with A188T. 31% (17/55) of MODY2 patients showed signs of insulin resistance. Conventional hypoglycaemia treatment did not improve the HbA1C in MODY2 patients when insulin resistance is not present.

CONCLUSIONS

Five novel GCK mutations have been identified in Chinese MODY. The defects in enzymatic activity and protein stability, together with alteration of GKRP binding on GCK mutants may synergistically contribute to the development of MODY2 hyperglycaemia. No treatment should be prescribed to MODY2 patients when insulin resistance is not present.

Prevalence of Diabetes Mellitus among Roma Populations-A Systematic Review

Background: The aim of this study was to estimate the prevalence of diabetes mellitus in the Roma population and compare it to the prevalence in the Caucasian population. Methods: Using the words “Roma”, “Gypsies”, “Romani”, and ”traveler” in combination with “diabetes, “metabolic syndrome”, “cardiovascular disease” and “health status” we searched the MEDLINE, Pubmed and Scopus databases for articles in English that focused on the prevalence of diabetes mellitus among Roma populations published until December 2017. Results: Five studies met the inclusion criteria. The results of four of them suggested a higher prevalence of diabetes among Romani compared to Caucasians but none of them reached the standards regarding representative samples and number of cases for a conclusive result. Conclusion: Although some of the existing studies suggest a substantial prevalence of diabetes among Roma populations and even a higher risk of developing diabetes for Roma persons compared to Caucasians, the number of published literature on this topic remains very low and insufficient in design and number of participants to draw any conclusions.

Traditional clinical criteria outperform high-sensitivity C-reactive protein for the screening of hepatic nuclear factor 1 alpha maturity-onset diabetes of the young among young Asians with diabetes

BACKGROUND

Young adults with diabetes in Asia represent a heterogeneous group. Using traditional clinical criteria to preselect individuals for testing for maturity-onset diabetes of the young (MODY) may exclude a large proportion from testing. High-sensitivity C-reactive protein (hs-CRP) has shown promise as a biomarker to differentiate hepatic nuclear factor 1 alpha (HNF1A)-MODY from type 2 diabetes. We aimed to compare the use of hs-CRP as a biomarker versus traditional criteria, to guide testing for HNF1A-MODY among a cohort of young adults with diabetes in Singapore.

METHODS

A total of 252 adults (age of onset ⩽45 years) and 20 children with diabetes were recruited. Using traditional criteria (family history of diabetes and onset of diabetes ⩽25 years) and an hs-CRP cut off of ⩽0.5 mg/l, 125 and 37 adults, respectively, were identified for HNF1A gene testing. All children underwent HNF1A gene testing.

RESULTS

Five adults (5/143, 3.5%) with HNF1A-MODY were identified. There were no HNF1A gene mutations among the children. Traditional criteria correctly identified all five HNF1A-MODY individuals (5/125, 4%), while applying an hs-CRP level of ⩽0.5 mg/l selected just 1 of these 5 for HNF1A gene testing (1/37, 2.7%). None of those with a positive GAD antibody or undetectable C-peptide level had HNF1A-MODY.

CONCLUSION

The use of hs-CRP to guide screening for HNF1A-MODY among Asian young adults with diabetes did not improve the diagnostic yield. Applying a combination of age of onset of diabetes under 25 years and a family history of diabetes alone could guide targeted HNF1A-MODY screening in Asians, with an expected yield of 4% diagnosed with HNF1A-MODY among those screened.

Precision medicine in diabetes prevention, classification and management

Diabetes has become a major burden of healthcare expenditure. Diabetes management following a uniform treatment algorithm is often associated with progressive treatment failure and development of diabetic complications. Recent advances in our understanding of the genomic architecture of diabetes and its complications have provided the framework for development of precision medicine to personalize diabetes prevention and management. In the present review, we summarized recent advances in the understanding of the genetic basis of diabetes and its complications. From a clinician's perspective, we attempted to provide a balanced perspective on the utility of genomic medicine in the field of diabetes. Using genetic information to guide management of monogenic forms of diabetes represents the best-known examples of genomic medicine for diabetes. Although major strides have been made in genetic research for diabetes, its complications and pharmacogenetics, ongoing efforts are required to translate these findings into practice by incorporating genetic information into a risk prediction model for prioritization of treatment strategies, as well as using multi-omic analyses to discover novel drug targets with companion diagnostics. Further research is also required to ensure the appropriate use of this information to empower individuals and healthcare professionals to make personalized decisions for achieving the optimal outcome.

Identification of four genes as novel susceptibility loci for early-onset type 2 diabetes mellitus, metabolic syndrome, or hyperuricemia

Given that early-onset type 2 diabetes mellitus (T2DM), metabolic syndrome (MetS), and hyperuricemia have been shown to have strong genetic components, the statistical power of a genetic association study may be increased by focusing on early-onset subjects with these conditions. Although genome-wide association studies have identified various genes and loci significantly associated with T2DM, MetS, and hyperuricemia, genetic variants that contribute to predisposition to these conditions in Japanese subjects remain to be identified definitively. We performed exome-wide association studies (EWASs) for early-onset T2DM, MetS, or hyperuricemia to identify genetic variants that confer susceptibility to these conditions. A total of 8,102 individuals aged ≤65 years were enrolled in the present study. The EWAS for T2DM was performed with 7,407 subjects (1,696 cases, 5,711 controls), that for MetS with 4,215 subjects (2,296 cases, 1,919 controls), and that for hyperuricemia with 7,919 subjects (1,365 cases, 6,554 controls). Single nucleotide polymorphisms (SNPs) were genotyped with Illumina Human Exome-12 DNA Analysis BeadChip or Infinium Exome-24 BeadChip arrays. The relationship of allele frequencies for 31,210, 31,521, or 31,142 SNPs that passed quality control for T2DM, MetS, or hyperuricemia, respectively, was examined with Fisher's exact test. To compensate for multiple comparisons of genotypes with T2DM, MetS, or hyperuricemia, we applied Bonferroni's correction for statistical significance of association. The EWAS of allele frequencies revealed that four, six, or nine SNPs were significantly associated with T2DM (P<1.60×10^-6), MetS (P<1.59×10^-6), or hyperuricemia (P<1.61×10^-6), respectively. Multivariable logistic regression analysis with adjustment for age and sex revealed that three, six, or nine SNPs were significantly related to T2DM (P<0.0031), MetS (P<0.0021), or hyperuricemia (P<0.0014). After examination of the association of identified SNPs to T2DM-, MetS-, or hyperuricemia-related traits, linkage disequilibrium of the SNPs, and results of previous genome-wide association studies, newly identified ZNF860 and OR4F6 were the susceptibility loci for T2DM, OR52E4 and OR4F6 for MetS, and HERPUD2 for hyperuricemia. Given that OR4F6 was significantly associated with both T2DM and MetS, we newly identified four genes (ZNF860, OR4F6, OR52E4, HERPUD2) that confer susceptibility to early-onset T2DM, MetS, or hyperuricemia. Determination of genotypes for the SNPs in these genes may prove informative for assessment of the genetic risk for T2DM, MetS, or hyperuricemia.

Type 2 diabetes in adolescents and young adults

The prevalence of type 2 diabetes in adolescents and young adults is dramatically increasing. Similar to older-onset type 2 diabetes, the major predisposing risk factors are obesity, family history, and sedentary lifestyle. Onset of diabetes at a younger age (defined here as up to age 40 years) is associated with longer disease exposure and increased risk for chronic complications. Young-onset type 2 diabetes also affects more individuals of working age, accentuating the adverse societal effects of the disease. Furthermore, evidence is accumulating that young-onset type 2 diabetes has a more aggressive disease phenotype, leading to premature development of complications, with adverse effects on quality of life and unfavourable effects on long-term outcomes, raising the possibility of a future public health catastrophe. In this Review, we describe the epidemiology and existing knowledge regarding pathophysiology, risk factors, complications, and management of type 2 diabetes in adolescents and young adults.

High risk of conversion to diabetes in first-degree relatives of individuals with young-onset type 2 diabetes: a 12-year follow-up analysis

AIM

Family history of diabetes is an established risk factor for Type 2 diabetes, but the impact of a family history of young-onset diabetes (onset < 40 years) on future risk of diabetes among first-degree relatives is unclear. In this prospective study, we examined the influence of family history of late- versus young-onset diabetes on the development of diabetes in a young to middle-aged Chinese population.

METHODS

Some 365 siblings identified through probands with Type 2 diabetes and 452 participants from a community-based health awareness project (aged 18-55 years) who underwent metabolic assessment during the period 1998-2002 were followed to 2012-2013 to determine their glycaemic status. Multivariate logistic regression was performed to investigate the association of family history of diabetes presented at different age categories with development of diabetes.

RESULTS

In this cohort, 53.4% (n = 167) of participants with a family history of young-onset diabetes, 30.1% (n = 68) of those with a family history of late-onset diabetes and 14.4% (n = 40) of those without a family history developed diabetes. Using logistic regression, family history of diabetes presented at ages ≥ 50, 40-49, 30-39 and < 30 years, increased conversion to diabetes with respective odds ratios of 2.4, 5.8, 9.4 and 7.0 (P < 0.001 for all), after adjustment for socio-economic status, smoking, obesity, hypertension and dyslipidaemia. Among participants without diabetes at baseline, risk association of family history of late-onset diabetes with incident diabetes was not sustained, whereas that of family history of young-onset diabetes remained robust on further adjustment for baseline glycaemic measurements.

CONCLUSIONS

First-degree relatives of people with Type 2 diabetes, especially relatives of those with young-onset diabetes, are at high risk for diabetes.

The relation between rice consumption, arsenic contamination, and prevalence of diabetes in South Asia

Rice is the major staple food for about two billion people living in Asia. It has been reported to contain considerable amount of inorganic arsenic which is toxic to pancreatic beta cells and disrupt glucose homeostasis. Articles and conference papers published between 1992 and 2017, indexed in Scopus, PubMed, EMBASE, Google, and Google scholar were used. Arsenic exposure has been associated with increased blood glucose and insulin levels, or decreased sensitization of insulin cells to glucose uptake. Several studies have shown the association between inorganic arsenic exposure and incidence of diabetes mellitus. Considerable amounts of arsenic have been reported in different types of rice which may be affected by cultivation methods, processing, and country of production. Use of certain microbes, fertilizers, and enzymes may reduce arsenic uptake or accumulation in rice, which may reduce its risk of toxicity. Combined exposure to contaminated rice, other foods and drinking water may increase the risk of diabetes in these countries. Maximum tolerated daily intake of arsenic contaminated rice (2.1 µg/day kg body weight) has been set by WHO, which may be exceeded depending on its content in rice and amount consumed. Hence, increased prevalence of diabetes in South Asia may be related to the consumption of arsenic contaminated rice depending on its content in the rice and daily amount consumed. In this review, we have focused on the possible relation between rice consumption, arsenic contamination, and prevalence of diabetes in South Asia.

Does Race/Ethnicity Have a Role in a Link Between Lower Urinary Tract Symptoms and Metabolic Syndrome?

Metabolic syndrome (MS) is a highly prevalent disease related to the risk of cardiovascular disease and diabetes. A large body of evidence has suggested a link between MS and the components of MS with lower urinary tract symptoms (LUTS) and benign prostatic hyperplasia (BPH) complex. The pathogenesis of MS is complex and not fully understood. Furthermore, recent results from epidemiological studies, including multiple Asian reports, have not been consistent. The risk of BPH is lower in Asian men compared with white men and the prevalence of MS varies by race and ethnicity. An elevated risk of Type 2 diabetes mellitus, hypertension, and dyslipidaemia is closely related to MS and is observed in Asian men even if their body mass index is low. However, the role of race and ethnic disparity in the link between MS and LUTS secondary to BPH is not elucidated. It has been suggested that the pathogenesis of LUTS is multifactorial rather than developing from BPH, which is the traditional concept. Lifestyle and genetic factors may substantially modify the risk of MS and LUTS/BPH. This comprehensive literature review summarises the scientific evidence of the racial/ethnic disparity regarding the association between MS and LUTS/BPH in order to improve current understanding of this controversial issue.

The Imbalance of B-Lymphocyte Subsets in Subjects with Different Glucose Tolerance: Relationship with Metabolic Parameter and Disease Status

B lymphocytes are involved in inflammation and are related to insulin resistance in obesity and type 2 diabetes (T2D). This study investigated the phenotype and frequency of B-lymphocyte subsets in subjects recently diagnosed with T2D (n = 60), impaired glucose regulation (IGR, n = 73), and normal glucose tolerance (NGT, n = 169) by flow cytometry. T2D subjects had an increased percentage of CD19⁺CD23⁺ (B-2) cells and a decreased percentage of CD19⁺CD23^- (B-1) cells attributing to CD19⁺CD23^-CD5^- (B-1b) cells, but not CD19⁺CD23^-CD5⁺ (B-1a) cells, compared to NGT and IGR subjects. The proportion of CD19⁺CD5⁺CD1d^hi (B10) cells did not differ between the IGR or T2D group and NGT controls. Of note, HbA1c and triglyceride showed a positive correlation with B-2 cells but an inverse correlation with B-1 and B-1b cells, which were independently associated with the presence of T2D by logistic regression models. In summary, this study shows an unbalanced proinflammatory phenotype of B-cell subsets correlated with glycemia and lipidemia in patients with T2D. Our data provide new insight into chronic activation of the immune system and subclinical inflammation in T2D. Further prospective studies are warranted to confirm our observations.

Neuroendocrine hormone amylin in diabetes

The neuroendocrine hormone amylin, also known as islet amyloid polypeptide, is co-localized, co-packaged and co-secreted with insulin from adult pancreatic islet β cells to maintain glucose homeostasis. Specifically, amylin reduces secretion of nutrient-stimulated glucagon, regulates blood pressure with an effect on renin-angiotensin system, and delays gastric emptying. The physiological actions of human amylin attribute to the conformational α-helix monomers whereas the misfolding instable oligomers may be detrimental to the islet β cells and further transform to β-sheet fibrils as amyloid deposits. No direct evidence proves that the amylin fibrils in amyloid deposits cause diabetes. Here we also have performed a systematic review of human amylin gene changes and reported the S20G mutation is minor in the development of diabetes. In addition to the metabolic effects, human amylin may modulate autoimmunity and innate inflammation through regulatory T cells to impact on both human type 1 and type 2 diabetes.

Male predominance in ketosis-prone diabetes mellitus

The incidence of ketosis-prone diabetes mellitus (KPDM) shows a higher prevalence in men. The clear male predominance of this syndrome and its underlying pathogenesis mechanisms are unclear. KPDM, once described as atypical diabetes mellitus, idiopathetic type 1 diabetes (type 1B diabetes) and flatbush diabetes, is an uncommon form of diabetes characterized by severe reversible insulin deficiency. KPDM was first described and mostly observed in males of African-American descent and recently in Asian populations, including Japanese and Chinese. Patients with KPDM often present acutely with diabetic ketoacidosis without any immunological autoantibody to islet antigens of classic type 1 diabetes but demonstrate clinical and metabolic features of type 2 diabetes. Accumulating data indicated that gender-related body fat distribution, hormonal and genetic factors are associated with the diabetic process and the human glucose homeostasis and metabolism. A controversial question is whether and to what degree those factors contribute to the phenomenon of male predominance in KPDM. The present review focuses on the role of gender hormones and other potential precipitating factors in explaining the male predominance in KPDM patients.

A first-degree relative with diabetes mellitus is an important risk factor for rural Thai villagers to develop type 2 diabetes mellitus

The screening of 609 villagers in rural areas of northeastern Thailand resulted in the detection of 110 (18.1%) new cases of type 2 diabetes (T2DM). The diagnoses were made on the basis of a glycated hemoglobin (HbA1c) value ≤ 6.5%. Among all those screened, 243 (40%) reported having a father or mother with T2DM. Among the new cases, 66 (60%) reported a first-degree relative, predominantly their mothers, who had the disease. Together with age and the body mass index, a mother or father with DM was strong risk factor for the development of T2DM (adjusted odds ratio = 2.9, 95% confidence interval = 1.84-4.57) when compared with the absence of a first-degree relative with DM. It is concluded that family history of a first-degree relative is an important additional information that might improve the validity of the screening procedure.

β-cell mass in people with type 2 diabetes

The early occurrence of β‐cell dysfunction has been broadly recognized as a critical determinant of the development and progression of type 2 diabetes. β‐cell dysfunction might be induced by insufficient β‐cell mass, by a dysfunction of the β‐cells, or both. Whether or not β‐cell dysfunction constitutes a cause of reduced β‐cells or vice‐versa currently remains unclear. The results of some studies have measured the loss of β‐cells in type 2 diabetic patients at between 22 and 63% by planimetric measurements. Because β‐cell hypertrophy has been noted in type 2 diabetic patients, the loss of β‐cell number should prove more profound than what has thus far been reported. Furthermore, β‐cell volumes are reduced even in patients with impaired fasting glucose. Such defects in β‐cell mass are associated with increased apoptosis rather than insufficient replication or neogenesis of β‐cells. With these results, although they still require clarification, the peak β‐cell mass might be determined at quite an early stage of life, and then might decline progressively over time as the result of exposure to harmful environmental influences over one’s lifetime. In this review, we have summarized the relevant studies regarding β‐cell mass in patients with type 2 diabetes, and then presented a review of the various causes of β‐cell loss in adults. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00072.x, 2010)

Familial young-onset diabetes, pre-diabetes and cardiovascular disease are associated with genetic variants of DACH1 in Chinese

In Asia, young-onset type 2 diabetes (YOD) is characterized by obesity and increased risk for cardiovascular disease (CVD). In a genome-wide association study (GWAS) of 99 Chinese obese subjects with familial YOD diagnosed before 40-year-old and 101 controls, the T allele of rs1408888 in intron 1 of DACH1(Dachshund homolog 1) was associated with an odds ratio (OR) of 2.49(95% confidence intervals:1.57-3.96, P = 8.4 × 10(-5)). Amongst these subjects, we found reduced expression of DACH1 in peripheral blood mononuclear cells (PBMC) from 63 cases compared to 65 controls (P = 0.02). In a random cohort of 1468 cases and 1485 controls, amongst top 19 SNPs from GWAS, rs1408888 was associated with type 2 diabetes with a global P value of 0.0176 and confirmation in a multiethnic Asian case-control cohort (7370/7802) with an OR of 1.07(1.02-1.12, P(meta)  = 0.012). In 599 Chinese non-diabetic subjects, rs1408888 was linearly associated with systolic blood pressure and insulin resistance. In a case-control cohort (n = 953/953), rs1408888 was associated with an OR of 1.54(1.07-2.22, P = 0.019) for CVD in type 2 diabetes. In an autopsy series of 173 non-diabetic cases, TT genotype of rs1408888 was associated with an OR of 3.31(1.19-9.19, P = 0.0214) and 3.27(1.25-11.07, P = 0.0184) for coronary heart disease (CHD) and coronary arteriosclerosis. Bioinformatics analysis revealed that rs1408888 lies within regulatory elements of DACH1 implicated in islet development and insulin secretion. The T allele of rs1408888 of DACH1 was associated with YOD, prediabetes and CVD in Chinese.

Mutations in KCNJ11 are associated with the development of autosomal dominant, early-onset type 2 diabetes

AIMS/HYPOTHESIS

More than 90% of Chinese familial early-onset type 2 diabetes mellitus is genetically unexplained. To investigate the molecular aetiology, we identified and characterised whether mutations in the KCNJ11 gene are responsible for these families.

METHODS

KCNJ11 mutations were screened for 96 familial early-onset type 2 diabetic probands and their families. Functional significance of the identified mutations was confirmed by physiological analysis, molecular modelling and population survey.

RESULTS

Three novel KCNJ11 mutations, R27H, R192H and S116F117del, were identified in three families with early-onset type 2 diabetes mellitus. Mutated KCNJ11 with R27H or R192H markedly reduced ATP sensitivity (E23K>R27H>C42R>R192H>R201H), but no ATP-sensitive potassium channel currents were detected in the loss-of-function S116F117del channel in vitro. Molecular modelling indicated that R192H had a larger effect on the channel ATP-binding pocket than R27H, which may qualitatively explain why the ATP sensitivity of the R192H mutation is seven times less than R27H. The shape of the S116F117del channel may be compressed, which may explain why the mutated channel had no currents. Discontinuation of insulin and implementation of sulfonylureas for R27H or R192H carriers and continuation/switch to insulin therapy for S116F117del carriers resulted in good glycaemic control.

CONCLUSIONS/INTERPRETATION

Our results suggest that genetic diagnosis for the KCNJ11 mutations in familial early-onset type 2 diabetes mellitus may help in understanding the molecular aetiology and in providing more personalised treatment for these specific forms of diabetes in Chinese and other Asian patients.

Diabetes and its comorbidities--where East meets West

Fetal programming associated with in utero exposure to maternal stress is thought to alter gene expression, resulting in phenotypes that promote survival in a pathogen-rich and nutrient-poor environment but substantially increase the risk of cardiovascular, metabolic and renal disorders (such as diabetes mellitus) in adults with obesity. These (epi)genetic phenomena are modified by environmental and socioeconomic factors, resulting in multiple subphenotypes and clinical consequences. In individuals from areas undergoing rapid economic development, which is associated with a transition from communicable to noncommunicable diseases, an efficient innate immune response can exaggerate obesity-associated inflammation. By contrast, in individuals with a genetic predisposition to autoimmune or monogenic diabetes mellitus, obesity can lead to atypical presentation of diabetes mellitus, termed 'double diabetes mellitus'. The increasingly young age at diagnosis of diabetes mellitus in developing countries results in prolonged exposure to glucolipotoxicity, low-grade inflammation and increased oxidative stress, which put enormous strain on pancreatic β cells and renal function. These conditions create a metabolic milieu conducive to cancer growth. This Review discusses how rapid changes in technology and human behaviour have brought on the global epidemic of metabolic diseases, and suggests that solutions will be based on using system change, technology and behavioural strategies to combat this societal-turned-medical problem.

Type 2 diabetes in East Asians: similarities and differences with populations in Europe and the United States

There is an epidemic of diabetes in Asia. Type 2 diabetes develops in East Asian patients at a lower mean body mass index (BMI) compared with those of European descent. At any given BMI, East Asians have a greater amount of body fat and a tendency to visceral adiposity. In Asian patients, diabetes develops at a younger age and is characterized by early β cell dysfunction in the setting of insulin resistance, with many requiring early insulin treatment. The increasing proportion of young-onset and childhood type 2 diabetes is posing a particular threat, with these patients being at increased risk of developing diabetic complications. East Asian patients with type 2 diabetes have a higher risk of developing renal complications than Europeans and, with regard to cardiovascular complications, a predisposition for developing strokes. In addition to cardiovascular-renal disease, cancer is emerging as the other main cause of mortality. While more research is needed to explain these interethnic differences, urgent and concerted actions are needed to raise awareness, facilitate early diagnosis, and encourage preventive strategies to combat these growing disease burdens.

Adiponectin trajectories before type 2 diabetes diagnosis: Whitehall II study

OBJECTIVE

The role of adiponectin in the natural history of diabetes is not well characterized. We set out to characterize prediagnosis trajectories of adiponectin in individuals who develop type 2 diabetes.

RESEARCH DESIGN AND METHODS

In a case-cohort study (335 incident diabetes case and 2,474 noncase subjects) nested in the Whitehall II study, serum adiponectin was measured up to three times per participant (1991-1993, 1997-1999, and 2003-2004). Multilevel models adjusted for age and ethnicity were fitted to assess 13-year trajectories of log-transformed adiponectin preceding diabetes diagnosis or a randomly selected time point during follow-up (year(0)) based on 755/5,095 (case/noncase) person-examinations.

RESULTS

Adiponectin levels were lower in diabetes case than in noncase subjects (median 7,141 [interquartile range 5,187-10,304] vs. 8,818 [6,535-12,369] ng/mL at baseline, P < 0.0001). Control subjects showed a modest decline in adiponectin throughout follow-up (0.3% per year, P < 0.0001) at higher levels in women than in men (difference at year(0): 5,358 ng/mL, P < 0.0001). Female case and early-onset case (age at diagnosis <52 years) subjects had a steeper decline than control subjects (slope difference -1.1% per year, P = 0.001 in females, -1.6% per year in early-onset case subjects, P = 0.034). In men, adiponectin slopes for case and noncase subjects were parallel. The slope differences by diabetes onset were largely attenuated after adjustment for changes in obesity, whereas the sex-specific slope differences were independent of obesity.

CONCLUSIONS

Lower adiponectin levels were observed already a decade before the diagnosis of diabetes. The marked sex difference in trajectories suggests that sex-specific mechanisms affect the association between adiponectin levels and diabetes development.

Familial early onset of type-2 diabetes mellitus and its complications

Background:

Globally, the prevalence of chronic, non-communicable diseases is increasing at an alarming rate. Furthermore, approximately 197 million people worldwide have impaired glucose tolerance. Consequently, diabetes is rapidly emerging as a global health problem that threatens to assume a pandemic level by 2030. In Indian population, genetic predisposition to trigger diabetes at an early age as compared to western counterpart has been focused very much.

Aim:

To gain further insight into the positive correlation between the diabetes and family history was the objective of this study.

Materials and Methods:

Patients attending the Diabetes Centre, K.L.E.S Dr. Prabhakar. Kore Hospital and Medical Research Centre; J. N. Medical College; KLE University Belgaum, Karnataka- India, were recruited, diagnosed and analyzed as per WHO criteria.

Results:

The prevalence of diabetes was higher among patients with diabetic mother (25.6%) compared to patients with diabetic father (21.2%) and there was early onset of type -2 diabetes among patients having both parents with diabetic when compared to other patients.

Conclusion:

Based on the present observation, it would be appropriate to emphasize again that a strong family history for diabetes, would signal at an early age, the onset of diabetes perhaps with its complications.

Trends in prevalence of diabetes in Asian countries

Diabetes is a major lifestyle disorder, the prevalence of which is increasing globally. Asian countries contribute to more than 60% of the world’s diabetic population as the prevalence of diabetes is increasing in these countries. Socio-economic growth and industrialization are rapidly occurring in many of these countries. The urban-rural divide in prevalence is narrowing as urbanization is spreading widely, adversely affecting the lifestyle of populations. Asians have a strong ethnic and genetic predisposition for diabetes and have lower thresholds for the environmental risk factors. As a result, they develop diabetes at a younger age and at a lower body mass index and waist circumference when compared with the Western population. The adverse effect of physical inactivity and fatty food are manifested as the increasing rate of overweightness and obesity, even among children. The health care budgets for the disease management are meager and the health care outcome is far from the optimum. As a result, complications of diabetes are common and the economic burden is very high, especially among the poor strata of the society. National endeavors are urgently needed for early diagnosis, effective management and for primary prevention of diabetes. This editorial aims to highlight the rising trend in prevalence of diabetes in Asia, its causative factors and the urgent need to implement national strategies for primary prevention of type 2 diabetes.

Update on mutations in glucokinase (GCK), which cause maturity-onset diabetes of the young, permanent neonatal diabetes, and hyperinsulinemic hypoglycemia

Glucokinase is a key regulatory enzyme in the pancreatic beta-cell. It plays a crucial role in the regulation of insulin secretion and has been termed the glucose sensor in pancreatic beta-cells. Given its central role in the regulation of insulin release it is understandable that mutations in the gene encoding glucokinase (GCK) can cause both hyper- and hypoglycemia. Heterozygous inactivating mutations in GCK cause maturity-onset diabetes of the young (MODY) subtype glucokinase (GCK), characterized by mild fasting hyperglycemia, which is present at birth but often only detected later in life during screening for other purposes. Homozygous inactivating GCK mutations result in a more severe phenotype presenting at birth as permanent neonatal diabetes mellitus (PNDM). A growing number of heterozygous activating GCK mutations that cause hypoglycemia have also been reported. A total of 620 mutations in the GCK gene have been described in a total of 1,441 families. There are no common mutations, and the mutations are distributed throughout the gene. The majority of activating mutations cluster in a discrete region of the protein termed the allosteric activator site. The identification of a GCK mutation in patients with both hyper- and hypoglycemia has implications for the clinical course and clinical management of their disorder.

Diabetes in Asia

Prevalence of type 2 diabetes has rapidly increased in native and migrant Asian populations. Diabetes develops at a younger age in Asian populations than in white populations, hence the morbidity and mortality associated with the disease and its complications are also common in young Asian people. The young age of these populations and the high rates of cardiovascular risk factors seen in Asian people substantially increase lifetime risk of cardiovascular disease. Several distinctive features are apparent in pathogenetic factors for diabetes and their thresholds in Asian populations. The economic burden due to diabetes at personal, societal, and national levels is huge. National strategies to raise public awareness about the disease and to improve standard of care and implementation of programmes for primary prevention are urgently needed.

Pregnancy and diabetes scenario around the world: China

Asians adopting a modern lifestyle have a higher risk of diabetes than their white counterparts living in high-income countries. Asian ethnicity is an independent risk factor for gestational diabetes mellitus (GDM), which is associated with a 2-fold increased risk of diabetes. In this burgeoning epidemic of diabetes, 40 million people in China are affected, with the most rapid rate of increase in disease prevalence in the young to middle-aged group. This rising trend of young onset diabetes is largely driven by the rising prevalence of childhood obesity/metabolic syndrome. In Asia, both low and high birth weights are independent risk factors for diabetes and metabolic syndrome. Apart from the high prevalence of maternal history of diabetes in women with diabetes, the metabolic milieu of GDM may have long-term effects on the metabolic profile and future risk of diabetes in the offspring. This complex interplay between environmental, genetic, and perinatal factors puts both mothers with a history of GDM and their offspring at risk of diabetes and metabolic syndrome, thus setting up a vicious cycle of "diabetes begetting diabetes." Given the public health burden of diabetes in low-income nations such as China, there is an urgent need to design and implement large-scale awareness and intervention programs targeted at these mother-offspring pairs to interrupt this transgenerational effect of diabetes and the socioeconomic and humanistic impacts.

Implication of genetic variants near TCF7L2, SLC30A8, HHEX, CDKAL1, CDKN2A/B, IGF2BP2, and FTO in type 2 diabetes and obesity in 6,719 Asians

OBJECTIVE

Recent genome-wide association studies have identified six novel genes for type 2 diabetes and obesity and confirmed TCF7L2 as the major type 2 diabetes gene to date in Europeans. However, the implications of these genes in Asians are unclear.

RESEARCH DESIGN AND METHODS

We studied 13 associated single nucleotide polymorphisms from these genes in 3,041 patients with type 2 diabetes and 3,678 control subjects of Asian ancestry from Hong Kong and Korea.

RESULTS

We confirmed the associations of TCF7L2, SLC30A8, HHEX, CDKAL1, CDKN2A/CDKN2B, IGF2BP2, and FTO with risk for type 2 diabetes, with odds ratios ranging from 1.13 to 1.35 (1.3 x 10(-12) < P(unadjusted) < 0.016). In addition, the A allele of rs8050136 at FTO was associated with increased BMI in the control subjects (P(unadjusted) = 0.008). However, we did not observe significant association of any genetic variants with surrogate measures of insulin secretion or insulin sensitivity indexes in a subset of 2,662 control subjects. Compared with subjects carrying zero, one, or two risk alleles, each additional risk allele was associated with 17% increased risk, and there was an up to 3.3-fold increased risk for type 2 diabetes in those carrying eight or more risk alleles. Despite most of the effect sizes being similar between Asians and Europeans in the meta-analyses, the ethnic differences in risk allele frequencies in most of these genes lead to variable attributable risks in these two populations.

CONCLUSIONS

Our findings support the important but differential contribution of these genetic variants to type 2 diabetes and obesity in Asians compared with Europeans.

Islet autoimmunity status in Asians with young-onset diabetes (12-40 years): association with clinical characteristics, beta cell function and cardio-metabolic risk factors

In this paper, the islet autoimmunity status and relation to clinical characteristics, beta cell function and cardio-metabolic risk factors in young-onset Asian diabetic patients are evaluated at baseline. The study population consisted of 912 patients (from China, India, Malaysia and Singapore) with age 12-40 years and diabetes duration <12 months. Autoantibodies to glutamic acid decarboxylase (GADA) and tyrosine phosphatase (IA-2A), beta cell function and cardio-metabolic risk parameters were assessed. Among our young patient cohort, 105 (11.5%) patients were GADA and/or IA-2A positives (Ab +ve). Ab +ve patients were younger, leaner, had more severe hyperglycaemia and lower beta cell function. The frequency of metabolic syndrome was significantly lower in Ab +ve patients (27%) compared to Ab -ve patients (54%). However, a substantial proportion of patients in both groups of patients had atherogenic dyslipidaemia, hypertension and albuminuria (micro or macro). In our study cohort, only one in 10 Asian youth with new-onset diabetes had evidence of islet autoimmunity. At least 60% of Ab +ve and 50% of Ab -ve patients demonstrated classical features of type 1 and type 2 diabetes respectively. Regardless of autoimmunity status, the cardio-metabolic risk factors, in particular atherogenic dyslipidaemia, hypertension and albuminuria were common in our patients with young-onset diabetes.

Etiology of early-onset type 2 diabetes in Indians: islet autoimmunity and mutations in hepatocyte nuclear factor 1alpha and mitochondrial gene

CONTEXT

Indians are at high risk of developing type 2 diabetes mellitus (T2DM) at an early age, despite their lower body mass index. Studies on the etiology of patients presenting as early-onset T2DM in this racial group are not available.

OBJECTIVE

The objective was to delineate the clinical features in young Indian patients with T2DM and to determine the role of mutations in the hepatocyte nuclear factor 1alpha (HNF1alpha) gene [MODY3 (maturity-onset diabetes of the young, type 3)], mitochondrial A3243G mutation, and islet autoimmunity in its etiology.

DESIGN

This was an observational cohort study.

SETTING

The setting was an outpatient diabetes clinic in a teaching hospital.

PATIENTS

Ninety-six consecutive young patients with T2DM (onset, <or=30 yr) were included in the study.

INTERVENTIONS

Glutamic acid decarboxylase and insulinoma antigen 2 antibodies, mitochondrial A3243G mutation, and the common HNF1alpha mutation P291fsinsC were measured in all patients. The entire HNF1alpha gene was studied for mutations in 32 subjects with onset less than 25 yr or with normal weight. The common HNF1alpha A98V polymorphism was studied in 91 patients.

RESULTS

The patients were clinically heterogeneous, with 42% having a normal body mass index. Glutamic acid decarboxylase antibodies were present in three (3%) subjects and mitochondrial A3243G mutation in one (1%) subject. The P291fsinsC mutation was not detected in any patient. A MODY3 mutation (R200W) was detected in one patient (3%). In this family, diabetes cosegregated with the R200W mutation in the proband and his youngest brother but not in three paternal uncles. The Val 98 allele was associated with T2DM (allele frequency, 0.14 vs. 0.03 in controls; odds ratio, 5.2; P < 0.001).

CONCLUSIONS

Despite a significant proportion of young Indian patients with T2DM having normal weight, islet autoimmunity, A3243G mitochondrial, and HNF1alpha gene mutations were infrequent.

A novel mutation, Ser159Pro in the NeuroD1/BETA2 gene contributes to the development of diabetes in a Chinese potential MODY family

OBJECTIVES

During examining the prevalence of mutations in NeuroD1/BETA2 gene in Chinese early-onset type 2 diabetic probands, a novel missense mutation, Ser159Pro in a potential MODY family was identified. To investigate the role of the mutation in early-onset diabetes, we studied its transcriptional activity on human insulin gene and clinical characteristics of the family with the mutation.

METHODS

Bi-directional sequencing of NeuroD1/BETA2 was performed in 85 early-onset type 2 diabetic probands without mutations in HNF4alpha, glucokinase, HNF1alpha, IPF-1 and HNF1beta genes, 95 late-onset type 2 diabetics with strong diabetic history and 87 non-diabetic control subjects. The function of the Ser159Pro to the transcription of a human insulin promotor-linked luciferase reporter gene in rat INS-1 cells was tested using Dual-Luciferase Reporter Assay System. Clinical phenotypes of the family with the Ser159Pro mutation were examined and analyzed.

RESULTS

A novel mutation, Ser159Pro were found in a 27-years-old proband with both parents had diabetes. The mutation was transmitted in the heterozygous state and co-segregated with diabetes in four out of five carriers from the paternal side. Expect for the proband, all of other members with this mutation in the family, however, were diagnosed with diabetes after 50-years-old. The functional study showed that the mutant protein exhibited a 25% reduction in transcriptional activity of insulin gene when compared with the wild type.

CONCLUSIONS

These results suggest that the novel Ser159Pro mutation in the NeuroD1/BETA2 gene contributes to the development of diabetes in a Chinese potential MODY family.

Overweight, family history of diabetes and attending schools of lower academic grading are independent predictors for metabolic syndrome in Hong Kong Chinese adolescents

BACKGROUND

Overweight and metabolic syndrome (MES) are emerging in both adult and paediatric populations.

AIMS

To study the prevalence of and associated risk factors for the MES, using the National Cholesterol Education Program definition, among Hong Kong Chinese adolescents studying in secondary schools.

METHODS

This was a cross-sectional, population-based study. A sample of 2115 Chinese adolescents was randomly selected from 14 secondary schools throughout Hong Kong. Data on anthropometric parameters, fasting blood and urine samples were collected in the school setting. Information regarding the adolescent's family history of diabetes, perinatal history, socioeconomic status and school grading was evaluated.

RESULTS

The prevalence of MES was 2.4% (95% confidence interval (CI) 1.8 to 3.1), with no significant difference between boys (2.9%) and girls (2%). The prevalence of various components of MES was 32.2% (30.2 to 34.2) for hypertension, 10.9% (9.6 to 12.2) for increased triglyceride, 9.0% (7.8 to 10.2) for central adiposity, 2.4% (1.7 to 3) for low high-density lipoprotein cholesterol and 0.3% (0.1 to 0.6) for impaired fasting glucose. On multivariate analysis, overweight (odds ratio 32.2; 95% CI 13.2 to 78.4), positive family history of diabetes (4.3; 1.3 to 14.1) and studying at schools of lower academic grading (5.5; 2.2 to 13.7) were found to be independent risk factors for MES.

CONCLUSION

A comparable prevalence of MES (2%) is observed in our study group Chinese adolescent girls and in US girls (2.1%), but a lower prevalence in Chinese boys (2.9%) than in US boys (6.1%). In our study, 41.8% harbour at least one component of the syndrome. Both families and schools should be alerted to this growing epidemic.

Mutations in the genes encoding the transcription factors hepatocyte nuclear factor 1 alpha (HNF1A) and 4 alpha (HNF4A) in maturity-onset diabetes of the young

Maturity-onset diabetes of the young (MODY) is a monogenic form of diabetes mellitus characterized by autosomal dominant inheritance, early age of onset (often <25 years of age), and pancreatic beta-cell dysfunction. MODY is both clinically and genetically heterogeneous, with six different genes identified to date; glucokinase (GCK), hepatocyte nuclear factor-1 alpha (HNF1A, or TCF1), hepatocyte nuclear factor-4 alpha (HNF4A), insulin promoter factor-1 (IPF1 or PDX1), hepatocyte nuclear factor-1 beta (HNF1B or TCF2), and neurogenic differentiation 1 (NEUROD1). Mutations in the HNF1A gene are a common cause of MODY in the majority of populations studied. A total of 193 different mutations have been described in 373 families. The most common mutation is Pro291fs (P291fsinsC) in the polycytosine (poly C) tract of exon 4, which has been reported in 65 families. HNF4A mutations are rarer; 31 mutations reported in 40 families. Sensitivity to treatment with sulfonylurea tablets is a feature of both HNF1A and HNF4A mutations. The identification of an HNF1A or 4A gene mutation confirms a diagnosis of MODY and has important implications for clinical management.

Comparisons of the outcomes on control, type of management and complications status in early onset and late onset type 2 diabetes in Asia

OBJECTIVE

To describe the clinical characteristics and chronic diabetic complications in early (EOD) and late onset type 2 diabetes mellitus (LOD) in Asia.

RESEARCH DESIGN AND METHODS

Retrospective collection of information (basic patient data, treatment received for diabetes, hypertension, dyslipidaemia, clinical measurements, complications, life-style management, etc.) on paper form and prospective collection of blood samples for HbA(1c) assessment were performed. Means, proportions and associated factors were analyzed using non-parametric and logistic regression.

RESULTS

The frequency of EOD (<30 years) varies in different Asian countries (0.4-5.3%). Overweight (BMI>or=23 kg/m2) was common in both EOD (60%) and LOD (66%). EOD was characterized by significantly higher levels of HbA(1c) (median 8.9% versus 7.9%) and FPG (median 9.8 mmol/L versus 8.3 mmol/L) but hypertension was less common (43% versus 59%). Lipid profiles (cholesterol and triglycerides) were similar between both groups of patients. Cataract was more common in LOD and was associated with onset age and diabetes duration whereas an increase in frequency of advanced eye disease, retinopathy and history of photocoagulation was found in EOD cohort.

CONCLUSIONS

In addition to diabetic control and duration of the disease, the onset age conferred risk to certain subsets of chronic complications in type 2 diabetes population.

Heterogeneity of early-onset and ketosis-resistant diabetes in Korean subjects--is it possible to determine cut-off age of early-onset type 2 diabetes?

OBJECTIVE

To investigate the heterogeneity of early-onset and ketosis-resistant diabetes and to define a not-arbitrary cut-off age for early-onset diabetes based on its clinical and metabolic characteristics, and diabetes complications.

METHODS

We classified 1015 early-onset diabetes subjects aged 21-40 into four groups (group I, age at diagnosis 21-25 years; group II, 26-30; group III, 31-35; group IV, 36-40). Familial and diabetic history, statue of insulin secretion, metabolic parameters, and diabetes complications were analyzed.

RESULTS

No significant difference in family history or the rate of diabetic complication was found in the four groups. Subjects with a 21 to a 25-year-old diabetes onset had the lowest serum C-peptide levels, with 50% of the cumulative 24-h urine C-peptide levels of the other three groups (p<0.0001). This group also had the lowest prevalence of hyperlipidemia and arterial hypertension (p<0.01 and <0.0001, respectively). Group III was found to have a higher prevalence of insulin insufficiency and hypertension than group IV.

CONCLUSION

Our data based on insulin secretory function and metabolic factors might suggest that a cut-off age of 26 years might be warranted in Korean patients. Korean early-onset type 2 diabetes patients tend to be non-obese and insulin secretory dysfunction.