Risk of type 1 diabetes development in children with incidental hyperglycemia: A multicenter Italian study

The application of precision medicine in monogenic diabetes

INTRODUCTION

Monogenic diabetes, a form of diabetes mellitus, is caused by a mutation in a single gene and may account for 1-2% of all clinical forms of diabetes. To date, more than 40 loci have been associated with either isolated or syndromic monogenic diabetes.

AREAS COVERED

While the request of a genetic test is mandatory for cases with diabetes onset in the first 6 months of life, a decision may be difficult for childhood or adolescent diabetes. In an effort to assist the clinician in this task, we have grouped monogenic diabetes genes according to the age of onset (or incidental discovery) of hyperglycemia and described the additional clinical features found in syndromic diabetes. The therapeutic options available are reviewed.

EXPERT OPINION

Technical improvements in DNA sequencing allow for rapid, simultaneous analysis of all genes involved in monogenic diabetes, progressively shrinking the area of unsolved cases. However, the complexity of the analysis of genetic data requires close cooperation between the geneticist and the diabetologist, who should play a proactive role by providing a detailed clinical phenotype that might match a specific disease gene.

Stress Hyperglycemia in Children and Adolescents as a Prognostic Indicator for the Development of Type 1 Diabetes Mellitus

Hyperglycemia is a common manifestation in the course of severe disease and is the result of acute metabolic and hormonal changes associated with various factors such as trauma, stress, surgery, or infection. Numerous studies demonstrate the association of adverse clinical events with stress hyperglycemia. This article briefly describes the pathophysiological mechanisms which lead to hyperglycemia under stressful circumstances particularly in the pediatric and adolescent population. The importance of prevention of hyperglycemia, especially for children, is emphasized and the existing models for the prediction of diabetes are presented. The available studies on the association between stress hyperglycemia and progress to type 1 diabetes mellitus are presented, implying a possible role for stress hyperglycemia as part of a broader prognostic model for the prediction and prevention of overt disease in susceptible patients.

Monogenic Diabetes Accounts for 6.3% of Cases Referred to 15 Italian Pediatric Diabetes Centers During 2007 to 2012

CONTEXT

An etiologic diagnosis of diabetes can affect the therapeutic strategy and prognosis of chronic complications.

OBJECTIVE

The aim of the present study was to establish the relative percentage of different diabetes subtypes in patients attending Italian pediatric diabetes centers and the influence of an etiologic diagnosis on therapy.

DESIGN, SETTING, AND PATIENTS

This was a retrospective study. The clinical records of 3781 consecutive patients (age, 0 to 18 years) referred to 15 pediatric diabetes clinics with a diagnosis of diabetes or impaired fasting glucose from January 1, 2007 to December 31, 2012 were examined. The clinical characteristics of the patients at their first referral to the centers, type 1 diabetes-related autoantibodies, molecular genetics records, and C-peptide measurements, if requested for the etiologic diagnosis, were acquired.

MAIN OUTCOME MEASURES

The primary outcome was to assess the percentage of each diabetes subtype in our sample.

RESULTS

Type 1 diabetes represented the main cause (92.4%) of diabetes in this group of patients, followed by monogenic diabetes, which accounted for 6.3% of cases [maturity onset diabetes of the young (MODY), 5.5%; neonatal diabetes mellitus, 0.6%, genetic syndromes, 0.2%]. A genetic diagnosis prompted the transfer from insulin to sulphonylureas in 12 patients bearing mutations in the HNF1A or KCNJ11 genes. Type 2 diabetes was diagnosed in 1% of the patients.

CONCLUSIONS

Monogenic diabetes is highly prevalent in patients referred to Italian pediatric diabetes centers. A genetic diagnosis guided the therapeutic decisions, allowed the formulation of a prognosis regarding chronic diabetic complications for a relevant number of patients (i.e.,GCK/MODY), and helped to provide genetic counseling.

Divergence between HbA1c and fasting glucose through childhood: implications for diagnosis of impaired fasting glucose (Early Bird 52)

OBJECTIVE

An HbA1c threshold of ≥ 6.5% has recently been adopted for the diagnosis of diabetes in adults, and of ≥ 5.7% to identify adults at risk. Little,however, is known of HbA1c's behaviour or diagnostic value in youth. Our aim was to describe the course of HbA1c during childhood, and its association with fasting glucose.

RESEARCH DESIGN AND METHODS

HbA1c and glucose were measured every year in a cohort of 326 healthy children (162 boys) from 5 to 15 years. Mixed effects modelling was used to establish the determinants of HbA1c and its development over time. ROC analysis was used to determine the diagnostic value of HbA1c in the 55 individuals who showed impaired fasting glucose(IFG – glucose ≥ 5.6 mmol/L).

RESULTS

Glucose rose progressively from 4.3 mmol/L at 5 years to 5.1 mmol/Lat 15 years, and although there were positive associations between HbA1c and glucose, from 10 to 13 years, HbA1c fell while glucose continued to rise. IFG developed in 55 children, but HbA1c exceeded 5.7% in only 16 of them. The maximum area under the ROC curve was 0.71 at the age of 14 (p<0.001), and the sensitivity and specificity were optimal at 50 and 80% respectively,corresponding to HbA1c of 5.4%.

CONCLUSIONS

Although HbA1c retains a positive association with glucose throughout childhood, it is weak, and their trends diverge from 10 years,suggesting that factors other than glycaemia systematically influence the variance of HbA1c in youth. These findings therefore limit the interpretation of HbA1c for the diagnosis of IFG during childhood.

Prognostic accuracy of continuous glucose monitoring in the prediction of diabetes mellitus in children with incidental hyperglycemia: receiver operating characteristic analysis

AIM

The purpose of this study is to evaluate continuous glucose monitoring (CGM) in predicting diabetes mellitus in children with incident hyperglycemia (IH) and negativity for some insular autoantibodies.

SUBJECTS AND METHODS

Thirty-one autoantibody-negative children who presented at our center with IH underwent a baseline assessment and were followed up for 23.8 months (range, 6-48 months). At the end of the follow-up, we compared the receiver operating characteristic (ROC) areas under the curve (AUCs) of metabolic markers from 17 children who developed diabetes (Group A; n=17) and 14 children who did not develop diabetes (Group B; n=14).

RESULTS

Only two oral glucose tolerance test (OGTT)-derived markers and three CGM-derived markers showed a good prognostic performance, with ROC AUCs indicating significant results (P<0.0001) for the following markers: 2-h glucose, OGTT (0.813; 95% confidence interval [CI] 0.621-0.954); AUC glucose, OGTT (0.832; 95% CI 0.611-0.950); CGM glucose measurement peak (0.803; 95% CI 0.621-0.923); percentage of CGM glucose measurements inside the range 70-125 mg/dL (0.866; 95% CI 0.695-0.961); and percentage of CGM measurements ≥126 mg/dL (0.889; 95% CI 0.724-0.973). The combination of the OGTT-derived markers did not increase the predictive value, but the combination of CGM markers with each other or with the OGTT markers yielded higher ROC AUCs (ranging from 0.828 to 0.945).

CONCLUSIONS

This is the first study showing that CGM is useful in predicting diabetes mellitus in children with IH.

Hyperglycaemia and β-cell antibodies: is it always pre-type 1 diabetes?

We describe 10-year-old girl with mild incidental hyperglycaemia, impaired glucose tolerance and GADA positivity. Family history for mild hyperglycaemia and GADA fluctuation alerted us to a possible MODY diagnosis which was confirmed by detection of GCK mutation c.626C>T; p.T209M. Weak or transient β-cell autoimmunity should not preclude genetic testing for MODY when the clinical features are suggestive.

Thyroid function and stress hormones in children with stress hyperglycemia

The purpose of the study is to determine the prevalence of stress hyperglycemia and to investigate how thyroid and stress hormones alter during stress hyperglycemia in children admitted to pediatric emergency wards. A prospective cross-sectional study was conducted in children, less than 19 years old, who were admitted to pediatric emergency wards of Nemazee and Dastgheib Hospitals, Shiraz, Southern Iran. Those patients taking steroids, beta-agonists or intravenously administered glucose before venipuncture, and patients with diabetes mellitus (DM) or thyroid diseases were excluded. Children with blood glucose ≥ 150 mg/dL during admission were regarded as cases. The controls were age- and- sex- matched, euglycemic children. Stress hormones including cortisol, insulin, growth hormone, and prolactin were measured, and thyroid function was tested with a radioimmunoassay (RIA) method in all cases and controls. The results showed that among 1,054 screened children, 39 cases (3.7 %) had stress hyperglycemia and 89 controls were included in the study. The occurrence of hyperglycemia was independent of sex, but it occurred mostly in children under 6 years old. Hyperglycemia occurred more frequently in patients with a positive family history of DM (odds ratio = 3.2, 95 % CI = 1.3-7.9, and P = 0.009). There were no significant differences between cases and controls regarding any hormones except higher cortisol, and lower total T3 and T4 in cases compared with controls. Neither of cases developed diabetes in the 24-month follow-up period. These findings led us to the conclusion that stress hyperglycemia is occasionally seen in critically ill patients. Among the stress hormones measured, only cortisol increased during hyperglycemia. It seems that hyperglycemia is not an important risk factor for future diabetes.

[Diabetes mellitus: clinical presentation and differential diagnosis of hyperglycemia in childhood and adolescence]

Diabetes mellitus is one of the most common chronic diseases in childhood. Despite being a clinical and etiopathogenically heterogeneous disorder, type 1 autoimmune diabetes accounts for more than 95% of cases in children. Recent advances have meant that a growing number of patients have been assigned to other subtypes of diabetes. In such cases, the correct diagnosis is facilitated by the fact that many of these rare causes of diabetes are associated with specific clinical syndromes or may present at a certain age. Many of them are also subsidiaries of molecular diagnosis. The aim of this review is to update the current knowledge in this field of pediatric diabetes, in an attempt to determine the most accurate diagnosis and its implications on appropriate treatment and prognosis.

Prevalence of type 1 diabetes autoantibodies (GADA, IA2, and IAA) in overweight and obese children

OBJECTIVE

Little is known about the prevalence of beta-cell autoantibodies in children with excess body weight. The prevalence of type 1 diabetes autoantibodies and its relation with hyperglycemia was analyzed in 686 overweight/obese children and adolescents.

RESEARCH DESIGN AND METHODS

All children underwent an oral glucose tolerance test, and anti-GAD, anti-IA2, and anti-IAA autoantibodies were measured. Autoantibody prevalence was evaluated in 107 normal-weight children for comparison.

RESULTS

A single autoantibody was present in 2.18% of overweight/obese subjects and 1.86% normal-weight subjects (P = NS). Postload glycemia was significantly higher in antibody-positive children (133 +/- 69.9 vs. 105.4 +/- 17.7 mg/dl, P < 0.0001) compared with autoantibody-negative subjects. No difference in autoantibody distribution was seen when our cohort was stratified by age, sex, SDS-BMI, pubertal stage, and homeostasis model assessment-insulin resistance (HOMA-IR).

CONCLUSIONS

The 2.18% prevalence of type 1 diabetes autoantibodies is similar to that reported in nonobese children. This study provided evidence that excess body weight and insulin resistance do not influence autoantibody frequency.

Maturity-onset diabetes of the young in children with incidental hyperglycemia: a multicenter Italian study of 172 families

OBJECTIVE

To investigate the prevalence of maturity-onset diabetes of the young (MODY) in Italian children with incidental hyperglycemia.

RESEARCH DESIGN AND METHODS

Among 748 subjects age 1-18 years with incidental hyperglycemia, minimal diagnostic criteria for MODY were met by 172 families. Mutational analyses of the glucokinase (GCK) and hepatocyte nuclear factor 1alpha (HNF1A) genes were performed.

RESULTS

We identified 85 GCK gene mutations in 109 probands and 10 HNF1A mutations in 12 probands. In GCK patients, the median neonatal weight and age at the first evaluation were lower than those found in patients with HNF1A mutations. Median fasting plasma glucose and impaired fasting glucose/impaired glucose tolerance frequency after oral glucose tolerance testing were higher in GCK patients, who also showed a lower frequency of diabetes than HNF1A patients.

CONCLUSIONS

GCK mutations are the prevailing cause of MODY (63.4%) when the index case is recruited in Italian children with incidental hyperglycemia.

Mild fasting hyperglycemia in children: high rate of glucokinase mutations and some risk of developing type 1 diabetes mellitus

BACKGROUND

Incidental hyperglycemia in children generates concern about the presence of preclinical type 1 diabetes mellitus (T1DM).

OBJECTIVE

To genetically evaluate two common forms of maturity-onset diabetes of youth (MODY), the short-term prognosis in children with mild hyperglycemia, and a positive family history of diabetes mellitus.

SUBJECTS

Asymptomatic children and adolescents (n = 14), younger than 15 yr, with fasting hyperglycemia, a positive family history of mild non-progressive hyperglycemia, and negative pancreatic autoantibodies were studied.

PATIENTS AND METHODS

Glucokinase gene (GCK) and hepatocyte nuclear factor 1 alpha gene (HNF1A) causing two common forms of MODY were sequenced. The clinical outcome was evaluated after a follow-up period of 2.8 +/- 1.3 yr.

RESULTS

GCK mutations were present in seven children. The confirmation of this diagnosis allowed discontinuation of insulin in two families and oral medications in three families. Mutations of HNF1A were not detected in any of the families. During the follow-up period, all the GCK mutation carrier children remained asymptomatic without medication and the last hemoglobin A1c levels were 6.4 +/- 0.7%. In the GCK-negative children (n = 7), one developed T1DM, corresponding to 7.2% of the total group. Mild fasting hyperglycemia persisted during follow-up in four GCK-negative children and normalized in the remaining two.

CONCLUSIONS

The presence of mild persistent hyperglycemia in any patient without autoantibodies should lead to genetic analysis of GCK, particularly if there is a positive family history. Furthermore, those without GCK mutations should be followed with repeat autoantibody testing, and other genetic types of diabetes should be considered if hyperglycemia worsens.

Oral glucose tolerance test in Italian overweight/obese children and adolescents results in a very high prevalence of impaired fasting glycaemia, but not of diabetes

BACKGROUND

Very few studies on glucose abnormalities in European overweight/obese children and adolescents are available, and scientific evidence on the value of standard oral glucose tolerance test (OGTT) in childhood is lacking. We therefore aimed to establish prevalence and features of impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and type 2 diabetes (T2D) in a large cohort of Italian overweight/obese children and adolescents and to assess the validity of standard OGTT in the paediatric population.

METHODS

This is a 1-year observational study conducted on 736 (535 overweight/obese and 201 normal weight) consecutive paediatric patients attending the outpatient clinic of Paediatric Endocrine Unit. Clinical and biochemical parameters were collected for all participants. All overweight/obese subjects underwent OGTT.

RESULTS

We observed a high prevalence of IFG (7.66%), more than twice that observed in other European children, but a low prevalence of IGT (3.18%) and T2D (0.18%). IFG was useless to predict IGT, having very low predictive value (7.3%) and sensitivity (17.6%). Compared to normal weight children, overweight/obese subjects showed significant differences in most metabolic and clinical parameters. In the overweight/obese group, having hyperglycaemia was associated to significantly higher blood pressure, homeostasis model assessment for insulin resistance, insulin and triglycerides.

CONCLUSIONS

In our children, the prevalence of IFG is higher than that reported in other European cohorts, whereas T2D is rare. IFG appears not useful to detect IGT in childhood. Paediatric diagnostic cut-points, glucose load and timing of sampling need to be further validated to define glucose abnormalities in obese children that, compared with normal weight subjects, already are characterised by a different metabolic phenotype.

Beta-cell autoimmunity in pediatric celiac disease: the case for routine screening?

OBJECTIVE

To evaluate the prevalence of beta-cell autoimmunity and the usefulness of a type 1 diabetes screening in patients with celiac disease.

RESEARCH DESIGN AND METHODS

We measured GAD antibodies (GADAs), insulinoma-associated protein 2 antigens (IA-2As), and insulin autoantibodies (IAAs) in 188 young Italian patients with celiac disease (66 male [35.1%]). Mean age at celiac disease diagnosis was 5.4 years (0.5-17.1), and mean celiac disease duration was 4.2 years (0-28.8). Celiac disease was diagnosed by jejunal biopsy after positivity for endomysial and tissue transglutaminase antibody was confirmed.

RESULTS

GADAs were positive in seven patients (3.7%), and IA-2As were positive in two patients. IAAs were negative in all cases. Metabolic evaluation was normal, and no patients developed diabetes during follow-up. There was no significant association among beta-cell autoimmunity and sex, age, pubertal stage, family history, or coexistence of other autoimmune disorders; compliance to a gluten-free diet was confirmed.

CONCLUSIONS

Our results showed a low prevalence of beta-cell autoimmunity and do not support a precocious screening for beta-cell autoimmunity in young celiac disease patients.

Association of alleles at polymorphic sites in the Osteopontin encoding gene in young type 1 diabetic patients

The Osteopontin (OPN) encoding gene, SPP1, can be considered as a candidate for genetic susceptibility to type 1 diabetes (T1D) because of its known function in immune response and inflammation. This work aimed to evaluate the role of SPP1 gene in susceptibility to T1D. Patients (238: 130 male, 108 female) and unaffected adult control individuals (137: 68 males and 69 females) have been genotyped for three variants in the SPP1 gene: -156 (G/GG) and -66 (T/G) in the promoter and a biallelic ins/del variant (TG/TGTG) at +245 in the first intron. The G allele at the -66 SNP had significantly higher frequency in controls than T1D patients. Interestingly, case-control comparison in males showed no significant association, whereas the association was confirmed in females. These results suggest that SPP1 can play a role as susceptibility gene, possibly by a sex-specific mechanism acting in the autoimmune process.

Hyperglycemia in celiac disease: not always pretype 1 diabetes?

Celiac disease (CD) is a T-cell-mediated enteropathy, triggered in genetically susceptible individuals by the ingestion of wheat gluten or related rye and barley proteins, whose clinical picture disease is considerably heterologous. Patients with CD are at high risk of autoimmune disorders; similarly, CD is frequent in patients with type 1 diabetes mellitus (T1DM), a disorder characterized by the immune-mediated beta-cell destruction, with the cooperation of environmental factors in genetically susceptible individuals. The immunological markers of beta-cell destruction are the autoantibodies to insulin, glutamic acid decarboxylase, and the protein tyrosine phosphatase. In absence of these markers, incidental hyperglycemia in children and adolescents appears unlikely to be associated with the progression to T1DM. We report a girl with CD and incidental hyperglycemia, without immunological markers of T1DM, with a family history for hyperglycemia, and diagnosed as maturity-onset diabetes of the young. We present this case as evidence that the possibility of monogenic forms of diabetes must be suspected in children with incidental hyperglycemia, a family history for mild hyperglycemia or diabetes, and absence of markers of beta-cell destruction, even if the patients are affected by an autoimmune disease.

Glucokinase mutations in young children with hyperglycemia

BACKGROUND

The etiology of mild hyperglycemia without ketoacidosis in young children is often unknown. Maturity onset diabetes of youth (MODY) is a form of diabetes mellitus (DM) characterized by fasting hyperglycemia without evidence for autoimmune destruction of beta-cells.

METHODS

We genetically analyzed four families of young children with fasting hyperglycemia with family histories of diabetes for mutations in the genes for hepatocyte nuclear factor 4 alpha (HNF4alpha), glucokinase (GCK), and hepatocyte nuclear factor 1 alpha (HNF1alpha), the genes responsible for MODY1, MODY2, and MODY3, respectively.

RESULTS

We identified mutations in GCK (Gly258Asp, Arg303Trp, and Arg191Gln) in three of the four families. Molecular genetic characterization in these children clarified the etiology and prognosis of the hyperglycemia and allowed discontinuation of insulin therapy in one family.

CONCLUSIONS

We conclude that molecular evaluation for MODY in children with mild fasting hyperglycemia without ketosis with family histories of diabetes can provide important prognostic information to guide therapy and exclude preclinical type 1 diabetes mellitus.

Anti-CD38 autoimmunity in children with newly diagnosed type 1 diabetes mellitus

AIMS

To test for anti-CD38 autoimmunity in children with newly-diagnosed type 1 diabetes mellitus (DM1).

METHODS

Serum anti-CD38 autoantibodies were detected by Western blot in 270 children (130 girls, 140 boys, mean age 8 +/- 4 years) with newly-diagnosed DM1 and 179 gender- and age-matched non-diabetic children. In 126 diabetic children, another blood sample was obtained 15 +/- 4 months after the diagnosis.

RESULTS

Anti-CD38 autoantibody titers at least 3 SD above the mean value for the control group were found in 4.4% of children with DM1 vs 0.6% of controls (chi2 = 5.8, p <0.016). No statistical differences were observed between anti-CD38 positive and negative patients in terms of phenotype. At follow-up, of six diabetic children who were positive for anti-CD38 antibodies, two were new cases. A positive correlation was found between the antibody titer of diabetic sera at diagnosis and follow up (r = 0.46, p <0.0001).

CONCLUSION

An autoimmune reaction against CD38, a protein expressed in human islets, is associated with newly-diagnosed DM1. In children with DM1, CD38 autoimmunity increases with time and persists.

Current literature in diabetes

In order to keep subscribers up-to-date with the latest developments in their field, John Wiley & Sons are providing a current awareness service in each issue of the journal. The bibliography contains newly published material in the field of diabetes/metabolism. Each bibliography is divided into 17 sections: 1 Books, Reviews & Symposia; 2 General; 3 Genetics; 4 Epidemiology; 5 Immunology; 6 Prediction; 7 Prevention; 8 INTERVENTION: a&rpar General; b&rpar Pharmacology; 9 Pathology: a&rpar General; b&rpar Cardiovascular; c&rpar Neurological; d&rpar Renal; 10 Endocrinology & Metabolism; 11 Nutrition; 12 Animal Studies; 13 Techniques. Within each section, articles are listed in alphabetical order with respect to author (9 Weeks journals - Search completed at 1st Aug 2001)