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Biomedical subjects

L Groop

Publications and source records attributed to L Groop.

At least 55 records · Page 3Linked to original sources
PubMed2000

Insulin sensitivity and insulin secretion in monozygotic and dizygotic twins.

AIMS/HYPOTHESIS: To estimate the heritability of insulin sensitivity and insulin secretion, both of which are considered to contribute to the development of Type II (non-insulin-dependent) diabetes mellitus. METHODS: Intraclass correlation coefficients and heritability estimates for insulin sensitivity (euglycaemic clamp) as well as first-phase and late-phase insulin secretion (intravenous glucose tolerance test) were calculated in 21 monozygotic and 20 dizygotic twin pairs of the same sex between 54 and 72 years of age. RESULTS: Intrapair correlations for all traits were consistently higher in monozygotic than in dizygotic pairs. Insulin secretion correlated significantly only between monozygotic (first-phase r = 0.55; p = 0.003 and late-phase r = 0.66; p < 0.001) twins giving heritability estimates of 0.55 and 0.58, respectively. Insulin-stimulated glucose uptake showed a more modest correlation between monozygotic twins (r = 0.46; p = 0.015). The heritability estimate was 0.37. The heritability estimate for waist-to-hip ratio was 0.76 in female and 0.70 in male twins. CONCLUSION/INTERPRETATION: Genetic variability seems to contribute to the variance of insulin sensitivity as well as of insulin secretion. In the current study, genetic variance accounted almost 60% for the variance in glucose-stimulated insulin secretion and almost 40% for the variance in insulin-stimulated glucose uptake. Our data is also compatible with findings in monogenic forms of diabetes in which genetic defects in insulin secretion play a predominant part in the pathogenesis of hyperglycaemia.

Aged↗
PubMed2000

Determinants of postabsorptive endogenous glucose output in non-diabetic subjects. European Group for the Study of Insulin Resistance (EGIR).

AIM/HYPOTHESIS: To gain insight into the physiologic determinants of postabsorptive endogenous glucose output (EGO) in humans. METHODS: We analysed the data of 344 non-diabetic subjects (212 men and 132 women) with a wide range of age (18-85 years) and body mass index (15-55 kg/m2) who participated in the European Group for the Study of Insulin Resistance (EGIR) project. Whole-body endogenous glucose output was measured by tracer ([3H]glucose) dilution at steady-state, peripheral insulin sensitivity (alpha glucose clearance/alpha insulin) was measured by the euglycaemic insulin (7 pmol x min(-1) x kg(-1)) clamp technique. RESULTS: Whole-body endogenous glucose output showed a large variability (mean = 768 +/- 202 micromol x min(-1), range 209-1512) and was strongly related to lean body mass (r = 0.63,p < 0.0001). This association entirely explained the endogenous glucose output being higher in men than in women (827 +/- 189 vs 674 x 187 micromol x min(-1), p < 0.0001), its relation to body mass (+ 10 +/- 2 per unit of body mass index, p < 0.0001) and its trend to decline with age (-1.1 +/- 0.7 micromol x min(-1) per year, p = 0.10). Although inversely related to one another (r = -0.41, p < 0.0001), peripheral insulin sensitivity and fasting plasma insulin were both independently associated with endogenous glucose output in an inverse fashion (with partial r's of 0.19 and 0.21, respectively, after adjusting for lean body mass and centre, p < 0.0001 for both). CONCLUSION/INTERPRETATION: Among non-diabetic subjects in the postabsorptive condition, total body endogenous glucose output variability is wide and is largely explained by the amount of lean mass; this, in turn, explains differences in total endogenous glucose output due to sex, obesity and age. Independently of the amount of lean mass, peripheral insulin resistance is associated with a higher endogenous glucose output independently of fasting plasma insulin concentration, suggesting coupled regulation of insulin action in peripheral tissues and the liver.

Adolescent↗
PubMed2000

Insulin secretion and insulin sensitivity in diabetic subgroups: studies in the prediabetic and diabetic state.

AIMS/HYPOTHESIS: To evaluate insulin sensitivity and insulin secretion in prediabetic and diabetic subjects with mutations in MODY1 (HNF-4 alpha) and MODY3 (HNF-1 alpha) genes, in subjects with GAD antibodies, latent autoimmune diabetes in adults and in subjects with the common form of Type II (non-insulin-dependent) diabetes mellitus. METHODS: Insulin secretion was measured as the incremental 30-min insulin (I30) and insulin glucose ratio (I:G30) during OGTT whereas insulin sensitivity was measured as the insulin sensitivity index during OGTT in 131 carriers of MODY mutations [NGT = 38, IFG/IGT = 21, diabetes mellitus (DM) = 72], in 293 subjects with GADA (NGT = 47, IFG/IGT = 29, DM = 217) and in 2961 subjects with a family history of the common form of Type II diabetes but without MODY mutations or GADA (NGT = 1360, IFG/IGT = 857, DM = 744). A subgroup of the subjects underwent a euglycaemic clamp (n = 210) and intravenous glucose tolerance test (n = 337) for the estimation of insulin sensitivity and first-phase insulin secretion. RESULTS: Non-diabetic subjects with MODY mutations had pronounced impaired insulin secretion (I30, I:G30) compared with the two other groups (p = 0.005). Normal or non-diabetic glucose tolerance was maintained by enhanced insulin sensitivity compared with the other two groups (p < 0.05 and p < 0.005). In contrast to patients with Type II diabetes and with adult latent autoimmune diabetes, MODY patients showed only a modest deterioration in insulin sensitivity at onset of diabetes. The 2-h glucose values inversely correlated with insulin sensitivity in subjects with GADA (r = -0.447, p < 0.001) and subjects from Type II diabetic families (r = -0.426, p < 0.001), whereas no such relation was observed in subjects with MODY mutations (r = 0.151, p = NS). There were no statistically significant differences in insulin secretion or insulin sensitivity between subjects with GADA or subjects with a family history of Type II diabetes, either at the NGT or the IFG/IGT stage. CONCLUSION/INTERPRETATION: Glucose-tolerant carriers of MODY mutations are characterised by a severe impairment in insulin secretion. Enhanced insulin sensitivity is the most likely explanation for the normal glucose tolerance. Whereas subjects with positive GADA or Type II diabetes have impaired insulin sensitivity with increasing glucose concentrations, MODY mutation carriers seem to be protected from the effect of glucose toxicity.

Adult↗
PubMed2000

Genetics of the metabolic syndrome.

The clustering of cardiovascular risk factors such as abdominal obesity, hypertension, dyslipidaemia and glucose intolerance in the same persons has been called the metabolic or insulin-resistance syndrome. In 1998 WHO proposed a unifying definition for the syndrome and chose to call it the metabolic syndrome rather than the insulin-resistance syndrome. Although insulin resistance has been considered as a common denominator for the different components of the syndrome, there is still debate as to whether it is pathogenically involved in all of the different components of the syndrome. Clustering of the syndrome in families suggests a genetic component. It is plausible that so-called thrifty genes, which have ensured optimal storage of energy during periods of fasting, could contribute to the phenotype of the metabolic syndrome. Common variants in a number of candidate genes influencing fat and glucose metabolism can probably, together with environmental triggers, increase susceptibility to the syndrome. Among these, the genes for beta 3-adrenergic receptor, hormone-sensitive lipase, lipoprotein lipase, IRS-1, PC-1, skeletal muscle glycogen synthase, etc. appear to increase the risk of the metabolic syndrome. In addition, novel genes may be identified by genome-wide searches.

Carrier Proteins↗
PubMed2000

The common PPARgamma Pro12Ala polymorphism is associated with decreased risk of type 2 diabetes.

Genetic association studies are viewed as problematic and plagued by irreproducibility. Many associations have been reported for type 2 diabetes, but none have been confirmed in multiple samples and with comprehensive controls. We evaluated 16 published genetic associations to type 2 diabetes and related sub-phenotypes using a family-based design to control for population stratification, and replication samples to increase power. We were able to confirm only one association, that of the common Pro12Ala polymorphism in peroxisome proliferator-activated receptor-gamma(PPARgamma) with type 2 diabetes. By analysing over 3,000 individuals, we found a modest (1.25-fold) but significant (P=0.002) increase in diabetes risk associated with the more common proline allele (85% frequency). Moreover, our results resolve a controversy about common variation in PPARgamma. An initial study found a threefold effect, but four of five subsequent publications failed to confirm the association. All six studies are consistent with the odds ratio we describe. The data implicate inherited variation in PPARgamma in the pathogenesis of type 2 diabetes. Because the risk allele occurs at such high frequency, its modest effect translates into a large population attributable risk-influencing as much as 25% of type 2 diabetes in the general population.

Adult↗
PubMed2000

Genetic variation in the gene encoding calpain-10 is associated with type 2 diabetes mellitus.

Type 2 or non-insulin-dependent diabetes mellitus (NIDDM) is the most common form of diabetes worldwide, affecting approximately 4% of the world's adult population. It is multifactorial in origin with both genetic and environmental factors contributing to its development. A genome-wide screen for type 2 diabetes genes carried out in Mexican Americans localized a susceptibility gene, designated NIDDM1, to chromosome 2. Here we describe the positional cloning of a gene located in the NIDDM1 region that shows association with type 2 diabetes in Mexican Americans and a Northern European population from the Botnia region of Finland. This putative diabetes-susceptibility gene encodes a ubiquitously expressed member of the calpain-like cysteine protease family, calpain-10 (CAPN10). This finding suggests a novel pathway that may contribute to the development of type 2 diabetes.

Adult↗
PubMed2000

Role of the Gly460Trp polymorphism of the alpha-adducin gene in primary hypertension in Scandinavians.

Previous studies have suggested that the Trp460 allele of the Gly460Trp polymorphism in the alpha-adducin gene is associated with salt sensitivity and primary hypertension. The present study was undertaken to evaluate if the Trp460 allele of this polymorphism is associated with primary hypertension in Scandinavians. To address this issue, 294 patients with primary hypertension and 265 normotensive control subjects from Sweden were examined and genotyped for the Gly460Trp polymorphism using polymerase chain reaction and restriction fragment length polymorphism methods. We then used a population of 80 patients with primary hypertension and 154 normotensive control subjects from Finland to replicate the findings. The frequency of the Trp460 allele was lower in hypertensive patients than in normotensive controls in the Swedish population (17.7% vs 23.0%; P = 0.03) and in the Finnish population (14.4% vs 19.5%; NS). Therefore we also performed a pooled analysis in which the frequency of the Trp460 allele was significantly lower in hypertensive patients than in normotensive controls (17.0% vs 21. 7%; P = 0.02). In subjects who did not receive antihypertensive medication (n = 447) there was no difference between carriers of the three different codon 460 genotypes (Trp-Trp; Trp-Gly and Gly-Gly) either for systolic (128 +/- 18; 127 +/- 15 and 129 +/- 17 mm Hg, NS) or for diastolic blood pressure (75.6 +/- 12.1; 74.7 +/- 9.3 and 75.0 +/- 10.4 mm Hg, NS). In conclusion, the lower frequency of the Trp460 allele in hypertensive patients than in normotensive controls strongly argues against a pathogenic role of this allele in primary hypertension. The results rather suggest that another variant in linkage disequilibrium with the Gly460Trp polymorphism increases susceptibility for hypertension. Journal of Human Hypertension (2000) 14, 43-46.

Alleles↗
PubMed2000

Association between a variant in the 11 beta-hydroxysteroid dehydrogenase type 2 gene and primary hypertension.

The enzyme 11 beta-hydroxysteroid dehydrogenase type 2 (11BHSD2) converts cortisol to cortisone in the kidney, thereby protecting the mineralocorticoid receptor from the mineralocorticoid actions of cortisol. The syndrome of Apparent Mineralocorticoid Excess (AME), a rare monogenic form of early onset hypertension with autosomal recessive inheritance, is caused by homozygous or compound heterozygous loss of function mutations in the 11BHSD2 gene. Association has been reported between a microsatellite marker flanking the 11BHSD2 gene (D16S496) and primary hypertension. The aim of this study was to identify variants in the 11BHSD2 gene and to test if such variants or the D16S496 are associated with primary hypertension, in Swedes. To address this, the coding sequences of the 11BHSD2 gene was screened for mutations in 20 patients with primary hypertension with single strand conformation polymorphism and direct DNA sequencing techniques. A polymorphism was identified in exon 3; G534A (Glu178Glu). This polymorphism and the D16S496 microsatellite were tested for association with primary hypertension in a population consisting of 292 patients with primary hypertension and 263 normotensive control subjects. The frequency of G534G homozygotes was higher in patients with primary hypertension than in normotensive control subjects (92.8% vs 87.8%; P < 0.05). The allele frequencies of the D16S496 microsatellite did not differ between the two groups (chi(2) = 11.0, df = 10; P = 0.36). In conclusion, over-representation of individuals homozygous for the G534 allele in hypertensive patients compared with control subjects suggests that a mutation in linkage disequilibrium with the G534A polymorphism could increase susceptibility to primary hypertension. Journal of Human Hypertension (2000) 14, 819-823

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed2000

Interaction between the Asn291Ser variant of the LPL gene and insulin resistance on dyslipidaemia in high risk individuals for Type 2 diabetes mellitus.

AIMS: Lipoprotein lipase (LPL) is a major regulator of triglyceride clearance. A genetic variant of the LPL gene on chromosome 8p22, Asn291Ser, has previously been associated with dyslipidaemia and an increased frequency of cardiovascular disease as well as familial disorders of lipoprotein metabolism. The aim of this study was to test whether the phenotypic expression of the LPL Asn291Ser variant is dependent upon glucose tolerance and insulin resistance. Therefore, the Asn291Ser variant was examined in 192 patients with Type 2 diabetes, 278 subjects with normal glucose tolerance who are first degree relatives of patients with Type 2 diabetes and 226 healthy control spouses without family history of diabetes. METHODS: The subjects were genotyped with an allele-specific mini-sequencing method. Insulin resistance was estimated using the homeostasis model assessment (HOMA) index. RESULTS: The frequency of the Asn/Ser genotype was significantly increased in normoglycaemic subjects with hypertriglyceridaemia (> 1.7 mmol/1), and was associated with dyslipidaemia and increased systolic blood pressure. There was a significant interaction between Asn291Ser and insulin resistance in normoglycaemic subjects, indicating that dyslipidaemia is more severe in Asn/ Ser carriers with reduced insulin sensitivity. The frequency of the Asn/Ser genotype was not increased in diabetic subjects with hypertriglyceridaemia, but was associated with increased systolic blood pressure. CONCLUSIONS: The Asn/Ser genotype of the LPL gene is associated with dyslipidaemia in normoglycaemic subjects, and the dyslipidaemic phenotype is more severe in insulin-resistant subjects. This association is not seen in diabetic subjects.

Aged↗
PubMed2000

High levels of nonesterified fatty acids are associated with increased familial risk of cardiovascular disease.

To address the question of whether elevated concentrations of nonesterified fatty acids (NEFAs) are associated with an increased risk of cardiovascular disease, we measured NEFA concentrations in 140 diabetic and 343 nondiabetic unrelated Swedish subjects with a family history of type 2 diabetes and related the findings to history of cardiovascular disease in their parents. Parents of nondiabetic offspring belonging to the quartile of highest NEFA concentrations had a higher risk of myocardial infarction (35% versus 16%, P<0.01) and stroke (45% versus 16%, P<0.0005) than did parents of offspring from the lowest NEFA quartile. In a multiple logistic regression analysis, a high NEFA concentration in offspring was significantly associated with myocardial infarction and stroke in their parents. No such relationship was observed between diabetic offspring and their parents. Assuming that the same relationship between NEFA concentrations and cardiovascular disease is seen in the offspring and their parents, the findings suggest that elevated NEFA concentration is a risk factor for cardiovascular disease and could be pathogenically involved in the atherosclerotic process.

Adult↗
PubMed2000

Effect of salt on insulin sensitivity differs according to gender and degree of salt sensitivity.

The aim of the present study was to investigate the effect of salt intake on insulin sensitivity and the relation between salt sensitivity and insulin sensitivity in genetically hypertension-prone individuals. Twenty-eight healthy subjects (13 men and 15 women) with a family history of hypertension were examined at baseline, after 1 week of salt restriction (10 mmol/d), and after 1 week of salt loading (240 mmol/d). Insulin sensitivity was measured with the hyperinsulinemic euglycemic clamp after the low- and high-salt diets. Salt sensitivity was defined as the difference in mean arterial blood pressure between the high-salt and the low-salt diets. There was no significant relationship between insulin sensitivity and salt sensitivity after either of the 2 diets. In the men, salt sensitivity was inversely related to plasma renin activity (r=-0.61, P=0.03) and plasma aldosterone (r=-0.74, P=0.004), whereas salt sensitivity in women was directly correlated with the salt-induced increase in body weight (r=0.68, P=0.005). In men, the high-salt diet induced a change in glucose disposal that was strongly correlated with the degree of salt sensitivity (r=0.83, P=0. 0004), plasma renin activity (r=-0.82, P=0.0006), and plasma aldosterone concentrations (r=-0.87, P=0.00009) (eg, the greater the salt sensitivity and the lower the activity of the renin-angiotensin-aldosterone system, the greater improvement in insulin sensitivity). No such relationships were observed in women. In conclusion, increased salt sensitivity and decreased activity of the renin-angiotensin-aldosterone system predict improved insulin sensitivity with high-salt intake compared with low-salt intake in men, suggesting an interaction among salt intake, salt sensitivity, the renin-angiotensin-aldosterone system, and insulin action.

Adult↗
PubMed2000

Genetic variants of thiazide-sensitive NaCl-cotransporter in Gitelman's syndrome and primary hypertension.

Gitelman's syndrome is an autosomal recessive disorder characterized by electrolyte disturbances and low blood pressure. The disease is caused by homozygous or compound heterozygous inactivating mutations in the thiazide-sensitive NaCl-cotransporter gene leading to reduced renal sodium reabsorption. We report 4 patients with Gitelman's syndrome from southern Sweden, all in whom we identified compound heterozygous mutations in the thiazide-sensitive NaCl-cotransporter gene (Gly439Ser, Gly731Arg, Gly741Arg, Thr304Pro, and 2745insAGCA), of which the latter 2 have not been described before. We hypothesized that such mutations in their heterozygous form protect against primary hypertension in the general population and that the gene may also harbor activating mutations that increase the risk for primary hypertension. Accordingly, the gene was screened for mutations in 20 patients with primary hypertension and in 20 normotensive subjects by single-strand conformation polymorphism and direct DNA sequencing. The Arg904Gln, Gly264Ala, and C1420T variants, found in the mutation screening of subjects without Gitelman's syndrome, were studied further. Population genotype frequencies were determined in 292 unrelated patients with primary hypertension and 264 unrelated normotensive subjects from southern Sweden. Gln904 homozygotes were overrepresented in hypertensive patients compared with normotensive subjects (5 of 292 versus 0 of 264; P:=0.03). In conclusion, we confirm that Gitelman's syndrome is caused by mutations in the thiazide-sensitive NaCl-cotransporter gene. Our results further suggest that subjects homozygous for the Gln904 variant have an increased risk for development of primary hypertension.

Adult↗
PubMed2000

Insulin and glucagon secretion in patients with slowly progressing autoimmune diabetes (LADA).

To metabolically characterize patients with slowly progressing autoimmune diabetes (LADA) of short duration we measured insulin, C peptide, and glucagon responses to glucose and arginine at three blood glucose levels (fasting and 14 and 28 mmol/L) in 11 patients with LADA, 11 patients with type 2 diabetes, and 14 healthy control subjects matched for age and body mass index. The acute insulin response to arginine was impaired in LADA vs. type 2 diabetes at all glucose levels, with the greatest impairment in the maximally stimulated insulin concentrations (P<0.04). In contrast, beta-cell sensitivity to glucose was unaltered in LADA and type 2 diabetes. The glucagon concentrations were elevated in both LADA and type 2 diabetic patients compared with healthy control subjects (P<0.02), but did not differ between the diabetic groups. In conclusion, patients with LADA share insulin resistance with type 2 diabetic patients, but display a more severe defect in maximally stimulated beta-cell capacity than patients with type 2 diabetes.

Adult↗
PubMed2000

Impaired insulin-stimulated expression of the glycogen synthase gene in skeletal muscle of type 2 diabetic patients is acquired rather than inherited.

To examine whether defective muscle glycogen synthase (GYS1) expression is associated with impaired glycogen synthesis in type 2 diabetes and whether the defect is inherited or acquired, we measured GYS1 gene expression and enzyme activity in muscle biopsies taken before and after an insulin clamp in 12 monozygotic twin pairs discordant for type 2 diabetes and in 12 matched control subjects. The effect of insulin on GYS1 fractional activity, when expressed as the increment over the basal values, was significantly impaired in diabetic (15.7 +/- 3.3%; P < 0.01), but not in nondiabetic (23.7 +/- 1.8%; P = NS) twins compared with that in control subjects (28.1 +/- 2.3%). Insulin increased GYS1 messenger ribonucleic acid (mRNA) expression in control subjects (from 0.14 +/- 0.02 to 1.74 +/- 0.10 relative units; P < 0.01) and in nondiabetic (from 0.24 +/- 0.05 to 1.81 +/- 0.16 relative units; P < 0.01) and diabetic (from 0.20 +/- 0.07 to 1.08 + 0.14 relative units; P < 0.01) twins. The effect of insulin on GYS1 expression was, however, significantly reduced in the diabetic (P < 0.003), but not in the nondiabetic, twins compared with that in control subjects. The postclamp GYS1 mRNA levels correlated strongly with the hemoglobin A1c levels (r = -0.61; P < 0.001). Despite the decrease in postclamp GYS1 mRNA levels, the GYS1 protein levels were not decreased in the diabetic twins compared with those in the control subjects (2.10 +/- 0.46 vs. 2.10 +/- 0.34 relative units; P = NS). We conclude that 1) insulin stimulates GYS1 mRNA expression; and 2) impaired stimulation of GYS1 gene expression by insulin in patients with type 2 diabetes is acquired and most likely is secondary to chronic hyperglycemia.

Aged↗
PubMed2000

Consequences of a family history of type 1 and type 2 diabetes on the phenotype of patients with type 2 diabetes.

OBJECTIVE: To investigate the impact of a family history of type 1 and type 2 diabetes on the phenotype of patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: In a population-based study, we compared the phenotype in 3 groups of patients with type 2 diabetes. The first group had no family history of diabetes (FH-, n = 148); the second group had a family history of type 2 diabetes only (FH+(TYPE2), n = 1,211); and the third group had a family history of both type 1 and type 2 diabetes (FH+(MIXED), n = 240). Furthermore, we studied the frequency of GAD antibodies (GADabs), HLA-DQB1 risk genotypes, and the presence of coronary heart disease (CHD) according to family history in unrelated patients with type 2 diabetes from 787 families (148 FH-, 546 FH+(TYPE2) and 93 FH+(MIXED)). RESULTS: Patients with no family history of diabetes were older at the onset of the disease, had a better beta-cell function (P = 0.004), and had higher HDL cholesterol concentrations (P = 0.006) than patients with a family history of diabetes. Patients with a family history of only type 2 diabetes had higher BMI and fasting C-peptide concentrations (P = 0.031) but lower frequency of GADab (11 vs. 23%, P = 0.001) and DQB1 risk genotypes (37 vs. 54%, P = 0.003) compared with patients with a family history of both type 1 and type 2 diabetes. In addition, hypertension (P = 0.05) and CHD (P = 0.031) were more common in FH+(TYPE2) than in FH+(MIXED) patients. In patients <60 years old, a family history of type 1 diabetes was associated with a reduced risk of CHD independent of age, hypertension, and HDL cholesterol concentrations. The results were similar when the GADab+ patients were excluded from the analysis. CONCLUSIONS: A family history of both type 1 and type 2 diabetes had a profound influence on the phenotype of patients with type 2 diabetes, which suggests a genetic interaction between type 1 and type 2 diabetes.

Aged↗
PubMed2000

Pathogenesis of type 2 diabetes: the relative contribution of insulin resistance and impaired insulin secretion.

Type 2 diabetes is characterised by both impaired insulin secretion and insulin resistance but their relative contribution to the development of hyperglycaemia may differ due to heterogeneity of the disease. Under most circumstances, insulin resistance is the earliest detectable defect in pre-diabetic individuals but it is not known whether this is the primary defect or secondary to other abnormalities such as abdominal obesity with excessive free fatty acid turnover and increased lipid deposits in muscle. Initially, enhanced insulin secretion can compensate for the insulin resistance but early phase insulin secretion is impaired. In the transition from normal to impaired and diabetic glucose tolerance, insulin sensitivity deteriorates about 40% whereas insulin secretion deteriorates 3-4 fold. In addition to insulin resistance, the metabolic syndrome includes hypertension, dyslipidaemia, obesity and microalbuminuria. In patients with manifest diabetes, chronic hyperglycaemia can result in further deterioration of insulin sensitivity and secretion (glucotoxicity), which is aggravated by elevated free fatty acids (lipotoxicity). Abdominal obesity and insulin resistance are strongly correlated and studies have aimed at understanding the genetic basis. Candidate genes for the metabolic syndrome include those for the beta 3-adrenergic receptor, lipoprotein lipase, hormone sensitive lipase, peroxisome proliferator-activated receptor-gamma, insulin receptor substrate-1 and glycogen synthase. Therefore, type 2 diabetes is multigenic and appears to represent a collision between thrifty genes and an affluent society. Successful management will require treatments targeted at defects of both insulin secretion and insulin resistance.

Diabetes Mellitus↗
PubMed1999

High frequency of mutations in MODY and mitochondrial genes in Scandinavian patients with familial early-onset diabetes.

AIMS/HYPOTHESIS: To investigate the contribution of mutations in maturity-onset diabetes of the young (MODY) and mitochondrial genes to early-onset diabetes with a strong family history of diabetes in a cohort with a high prevalence of Type I (insulin-dependent) diabetes mellitus. METHODS: Screening for sequence variants in the hepatocyte nuclear factor (HNF)-4alpha (MODY1), glucokinase (MODY2), HNF-1alpha (MODY3) genes and mitochondrial DNA was carried out in 115 Finnish and Swedish patients with early-onset ( </= 40 years) diabetes using the single strand conformation polymorphism (SSCP) technique and direct sequencing. Allele frequencies were compared with 118 patients with onset of diabetes Type II (non-insulin-dependent) diabetes mellitus after the age of 40 and 92 non-diabetic control subjects without a family history of diabetes. RESULTS: In total 52 sequence variants were found in the HNF-1alpha, HNF-4alpha and glucokinase genes, 12 of which were considered as MODY mutations. Three families had the A3243G mutation in the mitochondrial tRNA(Leu) gene, which resulted in an overall prevalence of these mutations of 13 %. CONCLUSION/INTERPRETATION: Among 115 Scandinavian families, mutations in the HNF-1alpha gene represented the most common cause of familial early-onset ( </= 40 years) diabetes: MODY3 (5.2 %) more than MODY2 (3.5 %) more than MIDD (2.6 %) more than MODY1 (1.7 %).

Adult↗