Nicoletta Sulli

High prevalence of glucokinase mutations in Italian children with MODY. Influence on glucose tolerance, first-phase insulin response, insulin sensitivity and BMI

Aims/hypothesis. The aim of this study was to assess the prevalence of glucokinase gene mutations in Italian children with MODY and to investigate genotype/phenotype correlations of the mutants. Methods. Screening for sequence variants in the glucokinase gene was performed by denaturing gradient gel electrophoresis and direct sequencing in 132 children with maturity onset diabetes of the young (MODY) and in 9 children with chronic fasting hyperglycaemia but without laboratory evidence for Type I (insulin-dependent) diabetes mellitus and with normoglycaemic parents (“non-classical” MODY). Results. Altogether 54 mutations were identified in the MODY group (54/132 or 41 %) and 3 among the “non-classical” MODY individuals (3/9 or 33 %). Paternity testing indicated that the latter mutations have arisen de novo. Mean fasting plasma glucose concentrations of the children with the mutant glucokinase was in the expected impaired fasting glucose range. In contrast, results of the oral glucose tolerance test showed a wide range from normal glucose tolerance (Group 1: 2-h OGTT = 6.7 ± 1.1 mmol/l; 11 patients) to diabetes (Group 2: 2-h OGTT = 11.5 ± 0.5 mmol/l; 9 patients), with the remaining in the impaired glucose tolerance range. Disruptive mutations (i. e. nonsense, frameshifts, splice-site) were equally represented in Groups 1 and 2 and were not clearly associated with an impaired first-phase insulin response. Surprisingly, 5 out of 11 children (or 45 %) in Group 1 were found to be overweight but no children in Group 2 were overweight. Sensitivity index (SI), calculated by a recently described method, was found to be significantly lower in Group 2 than in Group 1 (SI Group 2 = 0.0013 ± 0.0009 ml Kg–1 min–1/μU/ml; SI Group 1 = 0.0068 ± 0.0048, p < 0.0035). Conclusion/interpretation. Mutations in glucokinase are the first cause of MODY among Italian children selected through a low threshold limit of fasting plasma glucose (i. e. > 5.5 mmol). The lack of correlation between the molecular severity of glucokinase mutations, insulin secretion at intravenous glucose tolerance test and differences in glucose tolerance suggests that factors outside the beta cell are also involved in determining post-load glucose concentrations in these subjects. Our results seem to indicate that the differences observed in the 2-h responses at the OGTT among children with MODY 2 could be related to individual differences in insulin sensitivity. [Diabetologia (2001) 44: 898–905]

Continuous subcutaneous insulin infusion in children and adolescents with diabetes mellitus: decreased HbA1c with low risk of hypoglycemia.

AIM To evaluate blood glucose and HbA1c levels, insulin dosage, hypoglycemia rate and body mass index (BMI) at baseline, and at 3 and 6 months after initiation of continuous subcutaneous insulin infusion (CSII) in children and youth with type 1 diabetes mellitus (DM). METHODS A 6-month trial of pump therapy was carried out in 40 patients with type 1 DM and one with cystic fibrosis (CF) induced DM (25 males), aged 4-25 years (mean 13.5 +/- 4.2 [SD]; 4-8 years, n = 6; 8-10 years, n = 8; 10-12 years, n = 4; 12-15 years, n = 11; >15 years, n = 12). RESULTS HbA1c was significantly reduced from 9.5 +/- 1.7% to 8.6 +/- 1.2% at 3 months (p < 0.03), and at 6 months 8.8 +/- 1.5% (p < 0.05). The mean daily values of blood glucose, as well as individual mean values of blood glucose at fasting and before lunch, also exhibited a significant reduction (p < 0.05) at 3 and 6 months. There was a significant reduction in the number of hypoglycemic events (level of plasma glucose <3.3 mmol/l, calculated as number of events per patient/30 days) at 3 months (6.5 +/- 5.5 vs 2.8 +/- 3.3; p = 0.02) and at 6 months (6.5 +/- 5.5 vs 3.5 +/- 3.0; p = 0.04). The insulin requirement dropped by 27.2% (1.03 +/- 0.30 U/kg/day before starting CSII; 0.75 +/- 020 U/kg/day on insulin pump therapy onset; 0.76 +/- 0.18 U/kg/day at 3 months; 0.75 +/- 0.21 U/kg/day at 6 months). During the follow-up 0.10 events of diabetic ketoacidosis/patient/year were recorded. The patients exhibited no increase in BMI during the 6 months of follow-up. CONCLUSION CSII was safe and effective in improving short- and medium-term metabolic control in young adults, adolescents and younger children with DM.

A male patient with 48,XXYY syndrome: importance of distinction from Klinefelter's syndrome

The authors report a patient affected with mental retardation, dysarthria, bilateral testicular hypoplasia and extensive ulcers of the lower limbs. Clinical study and laboratory tests revealed 48,XXYY syndrome. The authors confirm the importance of differential diagnosis from Klinefelter syndrome, illustrating the parameters and the pathology of both syndromes. They discuss the hypotheses concerning the pathogenesis of the ulcerations, and stress the importance of clinical and genetic characterization, leading to a differentiated prognosis of social capacity and prospect of working.

The role of socio-economic and clinical factors on HbA1c in children and adolescents with type 1 diabetes: an Italian multicentre survey.

To identify the role of the familys socio‐economic and clinical characteristics on metabolic control in children and adolescents with type 1 diabetes.

GAD and IA-2 autoantibody detection in type 1 diabetic patient saliva

Some attempts have been made in assaying glutamic-acid decarboxylase autoantibodies (GADA) in type 1 diabetic patient (T1DM) saliva. However, these salivary assays did not show sufficient sensitivity and specificity in comparison to serum assays. In this study we evaluated the ability of a fluid-phase (35)S-radioimmunoassay to detect GADA and tyrosine phosphatase 2 autoantibodies (IA-2A) in 70 T1DM, 24 T1DM first degree relatives (FDR) and 76 healthy subject saliva. Paired saliva and serum samples were collected from each subject and analyzed. GADA were detected in 45/70 (64.3%) sera and 43/70 (61.4%) T1DM saliva, respectively. IA-2A were detected in 33/70 (47.1%) sera and 30/70 (42.9%) T1DM saliva, respectively. All FDR serum/saliva samples were autoantibody negative. In conclusion, we here report that GADA and IA-2A are detectable with high sensitivity and specificity in human saliva, a specimen which can be easily collected by non-invasive procedures and may represent a reliable tool for the study of T1DM autoimmunity.

Cytogenetic, Molecular, Immunologic, and Ultrastructural Study on an Established Cell Line of a Stage III Neuroblastoma

Neuroblastoma, representing about 7% of childhood malignant tumors, is the most common neoplasm in infancy and second in malignancy after lymphoma as a solid tumor outside the central nervous system in childhood. Its differential diagnosis from other tumors can be difficult and requires diagnostic approaches other than histological analysis.