Clinical benefits of switching to insulin degludec irrespective of previous basal insulin therapy in people with Type 1 or Type 2 diabetes: evidence from a European, multicentre, retrospective, non-interventional study (EU-TREAT).

AIMS: To investigate whether the benefits of switching to insulin degludec observed in the European retrospective chart review study EU-TREAT were dependent on the previous basal insulin used. METHODS: People with Type 1 or Type 2 diabetes were switched to insulin degludec from other basal insulins ≥6 months before data collection. Participants were stratified into three groups based on their previous basal insulin: insulin glargine 100 units/ml (Type 1: n=888; Type 2: n=259); insulin detemir (Type 1: n=726; Type 2: n=415); and neutral protamine Hagedorn (Type 1: n=53; Type 2: n=95). Their glycaemic control and hypoglycaemia incidence at 6 and 12 months post-switch vs pre-switch was then evaluated. RESULTS: Significant HbA1c reductions were achieved in all previous basal insulin groups for participants with Type 1 diabetes [insulin glargine 100 units/ml: -2.08 mmol/mol (-0.19%); insulin detemir: -2.40 mmol/mol (-0.22%)] and those with Type 2 diabetes [insulin glargine 100 units/ml: -5.90 mmol/mol (-0.54%); insulin detemir: -6.01 mmol/mol (-0.55%); neutral protamine Hagedorn: -2.73 mmol/mol (-0.25%)] at 6 months, except for the relatively small neutral protamine Hagedorn group in those with Type 1 diabetes [-1.75 mmol/mol (-0.16%)], where statistical significance was not reached. At 6 months in the Type 1 diabetes group, switching to insulin degludec from insulin glargine 100 units/ml resulted in significantly lower hypoglycaemia rates across all hypoglycaemia categories; for the insulin detemir group, this significance was also observed for severe and nocturnal non-severe hypoglycaemia, while the low number of people in the neutral protamine Hagedorn group resulted in nonsignificant reductions in hypoglycaemia rates. At 6 months in the people with Type 2 diabetes, switching to insulin degludec resulted in significantly lower rates of hypoglycaemia across all categories for all groups. Similar outcomes were observed at 12 months. CONCLUSIONS: Switching to insulin degludec from other basal insulins can improve glycaemic control and/or reduce hypoglycaemia risk in people with diabetes (although there was a nonsignificant reduction in HbA1c and hypoglycaemia rates for the neutral protamine Hagedorn group in Type 1 diabetes) under routine care.

Composite efficacy parameters and predictors of hypoglycaemia in basal-plus insulin therapy--a combined analysis of 713 type 2 diabetic patients.

AIMS: We aimed to identify predictors of hypoglycaemia in patients with poorly controlled type 2 diabetes treated with a single daily bolus of insulin glulisine on top of insulin glargine and oral antidiabetic drugs (basal-plus regimen). METHODS: We retrospectively analysed four large basal-plus trials including 713 patients (47% female) with type 2 diabetes, mean age of 59.9 ± 9.5 years and diabetes duration of 11 ± 7.0 years. Predictors for symptomatic, severe and nocturnal hypoglycaemia were identified by multivariate logistic regression analyses, calculation of odds ratios (ORs) and Wald 95% confidence intervals (CIs). RESULTS: Mean numbers of hypoglycaemic events per year were 4.64 ± 11.4 (symptomatic < 60 mg/dl), 0.59 ± 2.28 (nocturnal) and 0.03 ± 0.22 (severe). A total of 44.5% of patients reached the composite endpoint of glycated haemoglobin (HbA1c) <7.0% plus no severe hypoglycaemia, and 26.7% reached the composite of HbA1c <7.0% plus no symptomatic hypoglycaemia. Predictors of nocturnal and symptomatic hypoglycaemia were female gender (OR 1.82; 95% CI 1.07-3.11 and OR 1.89; 95% CI 1.31-2.78), diabetes duration >10 versus <5 years (OR 2.61; 95% CI 1.03-6.59 and OR 2.01; 95% CI 1.15-3.51) and higher basal insulin dose (per unit of increase) (OR 1.01; 95% CI 1.00-1.03 and OR 1.01; 95% CI 1.00-1.02). Conversely, a higher body mass index (BMI) (27-30 vs. <27 kg/m(2) and >30 vs. <27 kg/m(2) ) conferred a reduced risk of symptomatic hypoglycaemia with an OR of 0.53 (95% CI 0.31-0.90) and an OR of 0.61 (95% CI 0.39-0.97). CONCLUSIONS: Female gender, a long diabetes duration and higher basal insulin dose were predictors of hypoglycaemia, while protection was provided by BMI > 30. These results may help to successfully establish basal-plus insulin regimen in individual patients on their transition from basal-only to basal-bolus treatment.

Oxidative stress after a carbohydrate meal contributes to the deterioration of diastolic cardiac function in nonhypertensive insulin-treated patients with moderately well controlled type 2 diabetes.

The prevalence and prognostic importance of diastolic dysfunction in type 2 diabetes has only recently been appreciated. We tested the hypothesis that in insulin treated type 2 diabetes (D), carbohydrate consumption induces oxidative stress resulting in further impairment of diastolic function beyond structural myocardial stiffness. The effects of a pure carbohydrate breakfast (48 g) on oxidative stress and cardiac function were studied in the fasting and postmeal states in subjects without hypertension or overt cardiac disease (moderately well controlled D, n=21 and controls without D, n=20). Studied variables included systolic and early diastolic (E') myocardial velocities, traditional metabolic and hemodynamic parameters, serum nitrotyrosine, and sVCAM-1. In D compared to control subjects, the postmeal increase (∆) in glucose (1.44±2.78 vs. 0.11±0.72 mmol/l, p=0.04) and ∆nitrotyrosine (0.34±0.37 vs. -0.23±0.47 nM/l, p<0.001) were significantly higher. sVCAM-1 was higher in fasting and postmeal (p=0.02). E' was significantly lower in postmeal (7.3±1.3 vs. 9.6±1.3 cm/s, p<0.001) and fasting (p<0.001) whereas the rate pressure product was significantly higher (9 420±1 118 vs. 7 705±1 871 mm Hg/min, p<0.001). Multivariable regression models of the pooled data demonstrated that independent predictors for postmeal E' were ∆nitrotyrosine and septal thickness (R² 0.466) and for fasting E' age, ∆nitrotyrosine, and septal thickness (R² 0.400). In insulin requiring type 2 diabetes, carbohydrate consumption may induce oxidative stress that is associated with worsening diastolic function, indicating that this metabolic factor is an important determinant of diastolic dysfunction in the diabetic heart beyond the increase in structural myocardial stiffness.

Clinical manifestations and treatment options in patients with cirrhosis and diabetes mellitus.

BACKGROUND: Diabetes is frequently diagnosed in patients with cirrhosis and represents an important risk factor for morbidity and mortality. Pharmacological therapy is limited due to hepatotoxicity and the risk of hypoglycemia. Investigations on medical practice in this patient population, frequency of diabetes-associated complications and the impact of quality of metabolic control are rare. AIMS AND METHODS: A retrospective analysis was performed to compare the effects of hypoglycemic treatment, the achieved glycemic control under therapy, the prevalence of typical cirrhosis-related or microangiopathic complications, and cardiovascular comorbidities between a group of diabetic patients with cirrhosis (n = 87) and a nondiabetic cirrhotic population (n = 198). RESULTS: The prevalence of diabetes in our cohort was 30.5%. Of all diabetic patients, 39.1% received therapy which might potentially result in serious side effects in patients with end-stage liver disease. The rate of ongoing alcohol abuse (28.7%) and noncompliance under medication (41.4%) was high. Only 28.7% of all diabetic subjects showed satisfactory (as defined by HbA1c ≤ 6.5%) glycemic control under therapy. Patients achieving satisfactory control experienced a lower rate of certain cirrhosis-related complications such as hepatic encephalopathy (HE) and hepatocellular carcinoma (HCC), arterial hypertension, and hypercholesterolemia. HE was significantly more frequent in diabetic than nondiabetic cirrhotic patients.

Clinical update on insulin pump therapy in combination with continuous glucose monitoring.

In recent years, the treatment of type 1 diabetes has changed significantly. An important diagnostic and therapeutic support tool is the continuous glucose monitoring (CGM) showing its best performance when used in combination with an insulin pump therapy. Before the availability of CGM the consideration of glucose regulation and therapeutic success was based solely on selectively measured blood glucose levels and HbA1c. In contrast to the blood glucose measurements CGM measures in the interstitial fluid and opens a new dimension of diabetes therapy, we call it "glucose dynamics". The knowledge of the continuous glucose course and its trends has proved to be a highly relevant additional parameter which in practical terms has a particularly stabilizing influence on blood glucose profiles. CGM therefore offers the option of a fine-tuning of metabolic control by experienced heath care professionals and the patient, making blood glucose control in general and unplanned activities and problems in everyday life better controllable. However, despite the tremendous potential of CGM in combination with a pump therapy the basic settings of an effective pump therapy are crucial. Particularly the right basal insulin coverage as the first step is the key issue for success. With support of CGM there is an enormous potential to facilitate the adjustment and optimization of insulin pump therapy.

Risk of diabetic foot ulceration during treatment with insulin glargine and NPH insulin.

OBJECTIVE: To evaluate the effect of the long-acting basal insulin analog glargine compared with neutral protamine Hagedorn (NPH) insulin on the incidence of diabetic foot ulceration (DFU) in patients with diabetes in Germany. METHOD: A retrospective cohort study was performed using a representative German database (IMS Disease Analyzer) of patients with type 2 diabetes, who started a basal insulin therapy with either insulin glargine or NPH insulin, between July 2000 and September 2007, and continued this therapy for at least 24 months, and whose data were continuously documented.The occurrence of DFU was recorded beginning in the third year after therapy initiation and Kaplan-Meier curves were generated and compared using log-rank tests. Cox proportional hazard models were used to estimate the adjusted hazard ratio (HR) and 95% confidence intervals (CI) for the incidence of DFU. RESULTS: Patients who fulfilled the inclusion criteria (n=23 395) had started either on insulin glargine (n=9638) or on NPH insulin (n= 13 757).After adjustment for demographic and clinical variables, it was demonstrated that the relative risk to diabetes patients of developing DFS is 64% lower with insulin glargine than with NPH insulin therapy (HR=0.6 I; p=0.0405). CONCLUSION: The results suggest that, compared with NPH insulin, insulin glargine therapy significantly reduces the risk of DFS in patients with diabetes under real life conditions. Prospective long-term trials are needed to confirm these secondary data analysis results. DECLARATION OF INTEREST: There were no external sources of funding for this study.The authors have no conflicts of interest to declare.

[A 46-year-old patient with atrial fibrillation, elevated thyroid hormones and normal thyrotropine]. / Vorhofflimmern, erhöhte Schilddrüsenhormone und nicht supprimiertes TSH bei einem 46-jährigen Patienten.

We report on a 46 year old patient with a history of paroxysmal atrial fibrillation who presented to our emergency room. Diagnostic evaluation showed elevated free peripheral thyroid hormone levels and thyrotropine (TSH) hormone within normal limits. Ultrasound of the thyroid was normal, and thyroid autoantibodies were found in the normal range. There was a positive family history for thyroid dysfunction. TSH-producing adenoma (TSHoma) of the pituitary gland - the main differential diagnosis - was excluded by cranial MRI and laboratory tests. Familial thyroid hormone resistance (Refetoff syndrome) was suspected and could be confirmed by detection of a pathogenic mutation within the beta-thyroidhormone receptor gene. After spontaneous conversion to sinusrhythm the patient was treated with a beta(1)-selective betareceptor blocker. Up to now, no specific treatment is available to correct the defective beta-thyroidhormone receptor.

Optimized postprandial glucose control is associated with improved cardiac/vascular function - comparison of three insulin regimens in well-controlled type 2 diabetes.

In people with type 2 diabetes (T2DM), hyperglycemia has a negative impact on cardiac function and cardiovascular risk. Beneficial effects of improved postprandial glycemic control have been shown for cardiovascular risk only. To demonstrate these beneficial effects on myocardial function, we investigated well-controlled T2DM patients on three insulin regimens with different impact on postprandial glucose control. For 24 months, 61 T2DM participants in a randomized study had either conventional therapy (CT) with human premixed insulin b.d. (n=20), intensified therapy (ICT) with Lispro at meals and NPH at bedtime (n=24), or supplementary therapy (SIT) with human regular insulin at meals (n=17). Metabolism and cardiovascular function were assessed before and 2 hours after a standardized carbohydrate breakfast (48 g) using tissue Doppler to measure diastolic myocardial function (E'). Age, BMI, dose of insulin, cardiovascular disease, and medication were comparable between the groups. Hb1Ac was comparable with CT, ICT, and SIT (6.6+/-0.6, 6.2+/-0.6, and 6.4+/-0.7%) and so was fasting glucose. Post-meal glucose increment was 60+/-45 mg/dl with CT, but 15+/-52 and 8+/-58 mg/dl with ICT and SIT (p<0.006). E' was significantly lower (p<0.03) with CT (6.8+/-1.0 cm/s) vs. ICT (7.7+/-1.6) and SIT (7.8+/-1.2 cm/s), and correlated with post-meal glucose (r=-0.2644, p<0.046). Intima-media thickness and arterial stiffness parameters were higher in CT (p<0.04). In T2DM patients, the long-term insulin regimens CT, ICT, and SIT achieved overall good metabolic control with significant differences, however, in postprandial glucose increments. The regimens achieving better post-meal glucose control were associated with better myocardial/vascular function.

Comparison of insulin glargine versus NPH insulin in people with Type 2 diabetes mellitus under outpatient-clinic conditions for 18 months using a basal-bolus regimen with a rapid-acting insulin analogue as mealtime insulin.

AIMS: To assess the effects of a structured in-patient diabetes training programme in people with Type 2 diabetes mellitus on a basal-bolus regimen using insulin glargine or NPH insulin and rapid-acting insulin analogues with respect to glycaemic control, weight development and incidence of hypoglycaemia in an outpatient-clinic setting. PATIENTS AND METHODS: This was a prospective, non-randomized, single centre, comparative observational study including 119 subjects. Pre-study treatment was a basal-bolus regimen with NPH insulin and a rapid-acting insulin analogue. Subjects either continued with NPH insulin (n=56) or were switched over to insulin glargine (n=63) at the discretion of the investigator (aiming at equal numbers in each group). Patients then attended routine out-patient follow up visits for 18 months. RESULTS: HbA1c in the insulin glargine group improved statistically significant by -0.49%; [95%CI, -0.26, -0.71; p<0.001; HbA1c at endpoint 6.95+/-0.71%], whereas in the NPH group the reduction by -0.12% [95%CI, -0.31, 0.06; p=0.189; HbA1c at endpoint 7.22+/-0.74%] was statistically not significant. After 18 months of treatment the difference between treatment groups was 0.37% (p<0.015). Mean weight gain was significantly higher in the NPH group than in the glargine group (2.1 vs. 0.25 kg; p=0.025). A lower risk of hypoglycaemia in the glargine group (0.50 vs. 0.71 episodes/patient/month) did not reach statistical significance (p=0.081). CONCLUSIONS: Following a structured in-patient diabetes training programme glycaemic control in people with Type 2 diabetes mellitus on a basal-bolus regimen improved significantly only with insulin glargine suggesting that training alone may not be sufficient to further improve metabolic control in relatively well controlled patients on NPH insulin. Therefore, in addition to a structured training programme also the insulin regimen should be optimized, e.g. by introduction of an insulin analogue.

[How much do inpatient treated diabetics know about their disease?]. / Wie viel wissen stationär behandelte Diabetiker über ihre Erkrankung? Eine empirische Untersuchung in einem städtischen Klinikum in München.

AIM OF STUDY: The aim of the study was to find to find out which factors are able to predict the disease-specific knowledge of in-patient diabetic patients and to characterize this group of patients. METHODS: The disease-specific knowledge of diabetic patients of a Hospital in Munich, Germany (department of diabetology) was tested using a general questionnaire and a specific diabetes knowledge test. All data manipulation and statistical calculations were conducted with the statistical software package SAS (version 9.1). RESULTS: On average type-1-diabetics achieved 73% of the possible points in the knowledge test, type-2-diabetics achieved 68% of total points. In bivariate analyses, using logistic regression, existence of diabetes related complications was a significant predictor of poor knowledge (OR = 4.36; 95%-KI: 1.38-13.77) in type-1-diabetics. Other factors, e. g. lack of diabetes education were associated with low test results but reached no statistical significance (OR = 6.13; 95%-KI: 0.67-56.42). In multivariate logistic regression (female) gender was a significant risk factor for low test results (OR = 7.66; 95%-KI: 1.18-49.8). In type-2-diabetics lack of diabetes education (OR = 3.86; 95%-KI: 1.51-9.84), low self-assessment of information about diabetes (OR = 3.90; 95%-KI: 1.36-11.21) and lack of knowledge about diabetes diet (OR = 4.06; 95%-KI: 1.60-10.28) were predictors of poor test results. The existence of diabetes related complications was associated with poor test results but showed no statistical significance in multivariate analysis (OR = 2.99; 95%-KI: 0.85-10.43). CONCLUSIONS: There is a group of diabetic inward-patients that is less informed about diabetes and shows knowledge deficits in testing. These patients often lack diabetes education and show an unfavourable course of the disease, already having diabetes related complications. Type-2-diabetes patients who feel that they have poor information about their disease actually achieve lower results in knowledge testing. Efforts to assure diabetes education for these patients are essentially necessary.

Analysis of the mouse CD30 gene: a candidate for the NOD mouse type 1 diabetes locus Idd9.2.

Members of the tumor necrosis factor receptor superfamily play an important role in the initiation, expansion, and termination of an immune response. It has recently been demonstrated that one member of this family, CD30, plays a central role in maintaining peripheral tolerance by controlling the expansion of autoreactive CD8+ T-cells. In the present study, Cd30 was mapped to a 5.6-cM interval on chromosome 4 containing the type 1 diabetes susceptibility locus Idd9.2. We determined the intron/exon structure of Cd30 and sequenced the exons, as well as 1.8 kb of the 5' putative promoter region, from 6 different mouse strains. Remarkably, 63 sequence variants, both coding and noncoding, were found. A total of 27 sequence variants, 4 of which were nonsynonymous, were found between the diabetes susceptible NOD strain and the resistant B10 strain. Of these sequence variants, 19 are within the promoter region. However, no difference between NOD and the congenic strain NOD.B10 Idd9R1, which has the B10 allele of Cd30, was observed in CD30 expression at either the mRNA or protein level. Given its role in protecting against autoimmunity, one or more of the coding variants within CD30 is a good candidate for the Idd9.2 etiological variant.

The codon 17 polymorphism of the CTLA4 gene in type 2 diabetes mellitus.

Several studies have demonstrated an association of CTLA4 (IDDM12) alanine-17 with type 1 diabetes, but CTLA4 variants have not yet been investigated in type 2 diabetes. The CTLA4 exon 1 polymorphism (49 A/G) was analyzed in 300 Caucasian patients with type 2 diabetes and 466 healthy controls. All patients were negative for glutamate decarboxylase and islet cell antibodies. CTLA4 alleles were defined by PCR, single-strand conformational polymorphism, and restriction length fragment polymorphism analysis using BBV:I. The distribution of alleles as well as the genotypic and phenotypic frequencies were similar among patients and controls [AA, 42 vs. 39%; AG, 47 vs. 46%; GG, 11 vs. 15%, P = not significant (n.s.); A/G, 65/35% vs. 62/38%, P = n.s.; alanine/threonine 92/58% vs. 85/61%, P = n.s.]. However, detailed analysis of clinical and biochemical parameters revealed a tendency of GG (alanine/alanine) toward younger age at disease manifestation (46.8 +/- 0.8 vs. 49.5 +/- 0.8 yr, mean +/- SEM), lower body mass index (21.4 +/- 0.5 vs. 24.4 +/- 0.5 kg/m(2), P = 0.042), and basal C-peptide level (0.33 +/- 0.07 vs. 0.53 +/- 0.07nmol/L), as well as earlier start of insulin treatment (5.8 +/- 1.2 vs. 8.7 +/- 0.6 yr) and higher portion of patients on insulin (71 vs. 61%). Patients with the AA genotype were significantly less likely to develop microangiopathic lesions (P < 0.0005). No differences were found for hypertension or family history of type 2 diabetes. In conclusion, CTLA4 alanine-17 does not represent a major risk factor for type 2 diabetes. Additional studies on larger groups and different ethnic groups are warranted to clarify the association of the GG genotype with faster ss-cell failure and the lower rate of microvascular complications in AA carriers.

CTLA4 alanine-17 confers genetic susceptibility to Graves' disease and to type 1 diabetes mellitus.

The genetic susceptibility to Graves' disease and type 1 (insulin-dependent) diabetes mellitus is conferred by genes in the human leukocyte antigen region on the short arm of chromosome 6, but several other genes are presumed to determine disease susceptibility. Among those candidate genes is the cytotoxic T lymphocyte antigen 4 (CTLA4) located on chromosome 2q33 in man. We investigated the distribution of the CTLA4 exon 1 polymorphism (49 A/G) in Graves' disease and IDDM. This dimorphism at codon 17 results in an amino acid exchange (Thr/Ala) in the leader peptide of the expressed protein and was analyzed by PCR, single strand conformation polymorphism, and restriction fragment length polymorphism analysis in 305 patients with Graves' disease, 293 patients with IDDM, and 325 controls. Patients with Graves' disease had significantly more Ala alleles than controls, both as homozygotes (21% vs. 13%) and as heterozygotes (53% vs. 46%), and less Thr as homozygotes (26% vs. 42%; P < 2 x 10(-4). The phenotypic frequency of Ala-positive patients (73%) was significantly higher than of controls (58%; P = 10(-4); relative risk = 2). Patients with IDDM also had significantly more Ala alleles as homozygotes (19%) or heterozygotes (50%; P = 0.01). In conclusion, an alanine at codon 17 of CTLA4 is associated with genetic susceptibility to Graves' disease as well as to IDDM.

The presence or absence of a retroviral long terminal repeat influences the genetic risk for type 1 diabetes conferred by human leukocyte antigen DQ haplotypes. Belgian Diabetes Registry.

Major genetic susceptibility to type 1 diabetes mellitus maps to the human leukocyte antigen (HLA) region on chromosome 6p. During evolution, endogenous retroviral long terminal repeats (LTR) have been integrated at several sites within this region. We analyzed the presence of a solitary HERV-K LTR in the HLA DQ region (DQ-LTR3) and its linkage to DRB1, DQA1, and DQB1 haplotypes derived from 246 German and Belgian families with a patient suffering from type 1 diabetes mellitus. Segregation analysis of 984 HLA DQA1/B1 haplotypes showed that DQ-LTR3 is linked to distinct DQA1 and DQB1 haplotypes but is absent in others. The presence of DQ-LTR3 on HLA DQB1*0302 haplotypes was preferentially transmitted to patients from heterozygous parents (82%; P < 10(-6)), in contrast to only 2 of 7 DQB1*0302 haplotypes without DQ-LTR3. Also, the extended HLA DRB1*0401, DQB1*0302 DQ-LTR3-positive haplotypes were preferentially transmitted (84%; P < 10(-6)) compared with 1 of 6 DR-DQ matched DQ-LTR3 negative haplotypes. DQ-LTR3 is missing on most DQB1*0201 haplotypes, and those LTR3 negative haplotypes were also preferentially transmitted to patients (80%; P < 10(-6)), whereas DQB1*0201 DQ-LTR3-positive haplotypes were less often transmitted to patients (36%). Other DQA1/B1 haplotypes did not differ for DQ-LTR3 between transmitted and nontransmitted haplotypes. Thus, the presence of DQLTR3 on HLA DQB1*0302 and its absence on DQB1*0201 haplotypes are independent genetic risk markers for type 1 diabetes.

Innervation of the ring gland of Drosophila melanogaster.

In insects, peptidergic neurons of the central nervous system regulate the synthesis of the main developmental hormones. Neuropeptides involved in this neuroendocrine cascade have been identified in lepidopterans and dictyopterans. Since these organisms are not suitable for genetic research, we identified peptidergic brain neurons innervating the ring gland in Drosophila melanogaster. In larvae of Drosophila, ecdysteroids and juvenile hormones are produced by the ring gland, which is composed of the prothoracic gland, the corpus allatum, and the corpora cardiaca. Using the GAL4 enhancer trap system, we mapped those neurons of the central nervous system that innervate the ring gland. Eleven groups of neurosecretory neurons and their target tissues were identified. Five neurons of the lateral protocerebrum directly innervate the prothoracic gland or corpus allatum cells of the ring gland and are believed to regulate ecdysteroid and juvenile hormone titers. Axons of the circadian pacemaker neurons project onto dendritic fields of these five neurons. This connection might be the neuronal substrate of the circadian rhythms of molting and metamorphosis in Drosophila. Most of the neurons presented here have not been described before. The enhancer trap lines labeling them will be valuable tools for the analysis of neuronal as well as genetic regulation in insect development.

Interferon-gamma gene microsatellite polymorphisms in patients with Graves' disease.

Although some of the susceptibility to Graves' disease is conferred by genes in the human leucocyte antigen (HLA) region on the short arm of chromosome 6, other genetic factors must also predispose. Among the cytokines involved in thyroid autoimmunity interferon-gamma (IFN-gamma) plays a key role in the pathogenesis of Graves' disease. We therefore analyzed the first intron of the IFN-gamma gene for a dinucleotide (CA) repeat polymorphism on chromosome 12q. Two hundred two Caucasian patients with Graves' disease and 214 Caucasian controls were analyzed by polymerase chain reaction (PCR) and subsequent polyacrylamide gel electrophoresis technique: eight different alleles designated as IFN-gamma*1 to IFN-gamma*8 could be differentiated. Among Graves' disease patients IFN-gamma*5 (12.9% vs. 6.8%, p < 0.04) was significantly more frequent whereas IFN-gamma*2 (2.5% vs. 9.8%, p < 0.002) was significantly less frequent. Patients positive for the genetic susceptibility marker HLA DQA1*0501 had significantly more IFN-gamma*3 alleles (13.6% vs. 2.6%, p < 0.009) and IFN-gamma*5 alleles (22.1% vs. 7.6%, p < 0.03) compared with DQA1*0501 positive controls. Also, among patients with endocrine ophthalmopathy IFN-gamma*3 (17.9% vs. 4.2%, p < 8 x 10(-6)) and IFN-gamma*5 (18.9% vs. 7.0%, p < 0.003) were significantly more frequent compared with controls. Although a significant association of IFN-gamma microsatellite polymorphism was observed, only a small proportion of Graves' disease patients have these markers. Thus, it is likely that the detected microsatellite polymorphisms play only a minor role in the susceptibility to Graves' disease.

Genetic markers in diagnosis and prediction of relapse in Graves' disease.

Hyperthyroidism of Graves' disease takes an unpredictable clinical course in the long-term follow-up. Whereas roughly 30-60% of patients relapse after their first antithyroid drug treatment, the likelihood of remission in the remaining group can not be foreseen. We have analysed-retrospectively-patients with Graves' disease that had been on antithyroid drug treatment for one year and were followed up thereafter. Patients were investigated for a variety of clinical parameters like ophthalmopathy status and relapse or remission as well as gene polymorphisms of the HLA and other regions. Of the 259 patients analysed so far, patients with ophthalmopathy did not differ from those without for HLA DQA1 and CTLA4 alleles tested. Also, the subgroup of patients with relapses after antithyroid drug treatment showed no different distribution of those alleles from the group with long-term remission. This study also confirms that the allele HLA DQA1* 0501 confers susceptibility to Graves' disease, furthermore, that the CTLA4-alanine 17 allele is an additional predisposing factor.

Genetic susceptibility to type 1 diabetes: clinical and molecular heterogeneity of IDDM1 and IDDM12 in a german population.

Type 1 Diabetes mellitus (IDDM) results from an immune-mediated destruction of the pancreatic b-cells. The genetic predisposition is mainly confered by variations within MHC class II region on chromosome 6p as well as the CTLA4 gene located on chromosome 2q33. We analysed the transmission of HLA DQA1, DQB1, DRB1*04 alleles as well as an endogenous retroviral element (DQLTR3) in 130 families with a type 1 diabetic offspring in order to evaluate their role in genetic susceptibility to IDDM. Also the combined transmission of HLA and CTLA4 haplotypes was investigated. MHC class II alleles were typed using sequence-specific primer analysis. The presence or absence of DQLTR3 was defined by a nested PCR approach and CTLA4 microsatellite polymorphisms were detected with fluorescence-labeled primer on an automated sequencing system. By transmission distortion test we confirm the linkage of HLA DQA1*0501 DQB1*0201 (DR3 DQ2) as well as DQA1*0301 DQB1*0302 (DR4 DQ8) with IDDM. Whereas the combination with CTLA4 risk markers leads to the highest transmission rate on DR3 positive haplotypes, the predisposing CTLA4 variant does not modulate the risk on DR4 haplotypes. However, the absence of DQLTR3 on DR3, but its presence on DR4 haplotypes significantly increases the genetic risk for type 1 diabetes. Therefore predisposing MHC class II haplotypes are defined by distinct loci which differentially control genetic susceptibility. The combined transmission of protective CTLA4 and HLA DR3 as well as DR4 haplotypes confirms the dominant role of HLA class II polymorphisms in defining disease susceptibility to type 1 diabetes mellitus.

No association between the deltaF508 cystic fibrosis mutation and type 2 diabetes mellitus.

Cystic fibrosis (CF) is one of the most common recessively inherited disorders in Caucasian populations and is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. A three base deletion known as deltaF508 occurs on about 70%, of CF chromosomes and accounts for the high prevalence of the disease. Since type 2 diabetes mellitus occurs more frequently in relatives of patients with CF than in the normal population, we addressed the hypothesis whether heterozygosity for deltaF508 might be a genetic risk factor for type 2 diabetes. We screened 301 patients with type 2 diabetes mellitus which had been treated for at least three years from diagnosis by diet or oral antihyperglycemic agents. Healthy controls (n = 282) had no family history for diabetes. The genotype distribution did not differ significantly between patients with type 2 diabetes (2% heterozygotes) and controls (3% heterozygotes). According to these results, we conclude, that the deltaF508 mutation in its heterozygous form does not represent a major genetic risk factor for type 2 diabetes mellitus.

[Genetic risk markers in Graves' disease]. / Genetische Risikomarker des Morbus Basedow.

Graves' disease is exceptional as a disorder of stimulatory autoimmunity in comparison with all other endocrine autoimmunopathies. Research into its pathogenesis has so far focussed on the genetics next to characterisation of antibody-antigen as well as T-lymphocyte interactions. A multigenic predisposition similar to other autoimmune diseases has been proposed. Such polygenic disorders are frequent in the population and require special genetic epidemiological tools to dissect the many gene loci, where polymorphisms are readily detectable by several molecular typing assays. This review presents these tools and methods as well as the currently identified main susceptibility loci in the Human Leukocyte Antigen (HLA DQA1*0501), cytotoxic T-lymphocyte antigen 4 (CTLA4-ala17) as well as interferon-gamma (IFN-gamma *2) regions. Most of these predisposing alleles are shared risk factors in several endocrine autoimmune diseases. Further research is required to identify those gene variants that determine the individual course of thyroid stimulation or destruction.