| 1. |
- Antonelli, A, et al.
(författare)
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Autoimmunity to CD38 and GAD in Type I and Type II diabetes: CD38 and HLA genotypes and clinical phenotypes
- 2002
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 1432-0428 .- 0012-186X. ; 45:9, s. 1298-1306
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis. Autoantibodies against CD38 have been found in some patients with Type II (non-insulin-dependent) diabetes mellitus and have been shown to stimulate insulin secretion by cultured human islets. We tested whether this new form of autoimmunity, (i) overlaps with anti-GAD autoimmunity, (ii) identifies an insulin-deficient phenotype, (iii) is under the influence of genetic factors. Methods. We screened 496 adults by immuno-blot analysis in the Botnia Study (298 with Type II and 98 with Type I (insulin-dependent) diabetes mellitus, 100 non-diabetic control subjects). Results. CD38-autoantibodies were found in 8.4% of Type II diabetic patients (p<0.003 vs 0% of control subjects), particularly in anti-GAD positive (14% vs 6% of anti-GAD negative, p=0.0004). CD38ab were also found in 4% of Type I diabetic patients; in the whole study group, 59% of anti-CD38 positive had DQB1 *02 compared with 38% of anti-CD38 negative (p=0.04). On the OGTT, beta-cell function (as the ratio of insulin-to-glucose areas) was impaired (p=0.02) only in association with anti-GAD positivity (3.2 +/- 3.1 U/mol, mean +/- SD) but not in anti-CD38 positive patients (5.6 +/- 2.9) as compared with patients free of autoimmunity (4.5 +/- 4.6, p=NS). In 44 Type II diabetic patients (22 negative and 22 positive for anti-CD38), no mutations were detected in any of the 8 exons, 5' end of intron 1 or the 5' and 3' untranslated regions of the CD38 gene. The previously described missense mutation (Arg140Trp) in exon 3 was not found in this cohort. There was no association between the PvUII polymorphism and clinical phenotype. Conclusion. Anti-CD38 autoimmunity identifies a clinical phenotype similar to non-autoimmune Type II diabetes, with relative preserved beta-cell function and weak genetic influence.
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| 2. |
- Cervin, Camilla, et al.
(författare)
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Cosegregation of MIDD and MODY in a Pedigree: Functional and Clinical Consequences.
- 2004
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 53:7, s. 1894-1899
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was characterization of a family carrying two mutations known to cause monogenic forms of diabetes, the M626K mutation in the HNF1α gene (MODY3) and the A3243G in mtDNA. β-Cell function and insulin sensitivity were assessed with the Botnia clamp. Heteroplasmy of the A3243G mutation and variants in type 2 diabetes susceptibility genes were determined, and transcriptional activity, DNA binding, and subcellular localization of mutated HNF1α were studied. Thirteen family members carried the mutation in mtDNA; 6 of them also had the M626K mutation, whereas none had only the M626K mutation. The protective Ala12 allele in peroxisome proliferator–activated receptor (PPAR)γ was present in two nondiabetic individuals. Carriers of both mtDNA and HNF1α mutations showed an earlier age at onset of diabetes than carriers of only the mtDNA mutation (median 22 vs. 45 years) but no clear difference in β-cell function or insulin sensitivity. In vitro, the M626K mutation caused a 53% decrease in transcriptional activity in HeLa cells. The mutated protein showed normal nuclear targeting but increased DNA binding. These data demonstrate that several genetic factors might contribute to diabetes risk, even in families with mtDNA and HNF1α mutations.
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| 3. |
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| 4. |
- Florez, Jose C., et al.
(författare)
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Haplotype Structure and Genotype-Phenotype Correlations of the Sulfonylurea Receptor and the Islet ATP-Sensitive Potassium Channel Gene Region.
- 2004
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 53:5, s. 1360-1368
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Tidskriftsartikel (refereegranskat)abstract
- The genes for the sulfonylurea receptor (SUR1; encoded by ABCC8) and its associated islet ATP-sensitive potassium channel (Kir6.2; encoded by KCNJ11) are adjacent to one another on human chromosome 11. Multiple studies have reported association of the E23K variant of Kir6.2 with risk of type 2 diabetes. Whether and how E23K itself—or other variant(s) in either of these two closely linked genes—influences type 2 diabetes remains to be fully determined. To better understand genotype-phenotype correlation at this important candidate gene locus, we 1) characterized haplotype structures across the gene region by typing 77 working, high-frequency markers spanning 207 kb and both genes; 2) performed association studies of E23K and nearby markers in >3,400 patients (type 2 diabetes and control) not previously reported in the literature; and 3) analyzed the resulting data for measures of insulin secretion. These data independently replicate the association of E23K with type 2 diabetes with an odds ratio (OR) in the new data of 1.17 (P = 0.003) as compared with an OR of 1.14 provided by meta-analysis of previously published, nonoverlapping data (P = 0.0002). We find that the E23K variant in Kir6.2 demonstrates very strong allelic association with a coding variant (A1369S) in the neighboring SUR1 gene (r2 > 0.9) across a range of population samples, making it difficult to distinguish which gene and polymorphism in this region are most likely responsible for the reported association. We show that E23K is also associated with decreased insulin secretion in glucose-tolerant control subjects, supporting a mechanism whereby β-cell dysfunction contributes to the common form of type 2 diabetes. Like peroxisome proliferator–activated receptor γ, the SUR1/Kir6.2 gene region both contributes to the inherited risk of type 2 diabetes and encodes proteins that are targets for hypoglycemic medications, providing an intriguing link between the underlying mechanism of disease and validated targets for pharmacological treatment.
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| 5. |
- Frayling, Timothy M., et al.
(författare)
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A Genome-Wide Scan in Families With Maturity-Onset Diabetes of the Young: Evidence for Further Genetic Heterogeneity.
- 2003
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 52:3, s. 872-881
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Tidskriftsartikel (refereegranskat)abstract
- Maturity-onset diabetes of the young (MODY) is a heterogeneous single gene disorder characterized by non–insulin-dependent diabetes, an early onset and autosomal dominant inheritance. Mutations in six genes have been shown to cause MODY. Approximately 15–20% of families fitting MODY criteria do not have mutations in any of the known genes. These families provide a rich resource for the identification of new MODY genes. This will potentially enable further dissection of clinical heterogeneity and bring new insights into mechanisms of β-cell dysfunction. To facilitate the identification of novel MODY loci, we combined the results from three genome-wide scans on a total of 23 families fitting MODY criteria. We used both a strict parametric model of inheritance with heterogeneity and a model-free analysis. We did not identify any single novel locus but provided putative evidence for linkage to chromosomes 6 (nonparametric linkage [NPL]score 2.12 at 71 cM) and 10 (NPL score 1.88 at 169–175 cM), and to chromosomes 3 (heterogeneity LOD [HLOD] score 1.27 at 124 cM) and 5 (HLOD score 1.22 at 175 cM) in 14 more strictly defined families. Our results provide evidence for further heterogeneity in MODY.
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| 6. |
- Lethagen, ÅsaLinda, et al.
(författare)
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Glutamic acid decarboxylase antibody positivity is associated with an impaired insulin response to glucose and arginine in nondiabetic patients with autoimmune thyroiditis
- 2002
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - 1945-7197. ; 87:3, s. 1177-1183
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Tidskriftsartikel (refereegranskat)abstract
- To study whether antibodies to glutamic acid decarboxylase (GADab) are associated with subclinical beta-cell damage and impaired insulin secretion, we screened 441 nondiabetic patients with autoimmune thyroiditis (AT) for GADab, and 15 (3.4%) were found positive. Antibodies to IA-2 were found in two GADab+ and one GADab- patients. We matched 11 GADab+ and 13 GADab- AT patients who were euthyroid on thyroxin supplementation, and 13 control subjects for sex, age, and body mass index and measured insulin, C-peptide, and glucagon response to glucose and arginine at three blood glucose concentrations (fasting, 14 mmol/liter, >25 mmol/liter). In the fasting state, all groups had similar blood glucose concentration and HbA1c level, but the serum insulin concentration was higher in the AT patients compared with the control subjects (P < 0.04). The acute insulin response to arginine was lower in GADab+ than in GADab- thyroiditis subjects at glucose concentration of 14 and >25 mmol/liter (AIR,4: 76.8 +/- 52.0 vs. 158.2 +/- 118.2 mU/liter, P = 0.040; AIR(>25): 84.3 +/- 64.4 vs. 167.9 +/- 101.5 mU/liter, P = 0.035). In conclusion, GADab were associated with a decreased insulin secretion capacity in nondiabetic subjects with thyroiditis, which suggests that GADab positivity could be a marker of subclinical insulitis.
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| 7. |
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| 8. |
- Lindgren, Cecilia, et al.
(författare)
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Contribution of known and unknown susceptibility genes to early-onset diabetes in scandinavia: evidence for heterogeneity.
- 2002
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Ingår i: Diabetes. - : American Diabetes Association. - 1939-327X .- 0012-1797. ; 51:5, s. 1609-1617
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Tidskriftsartikel (refereegranskat)abstract
- In an attempt to identify novel susceptibility genes predisposing to early-onset diabetes (EOD), we performed a genome-wide scan using 433 markers in 222 individuals (119 with diabetes) from 29 Scandinavian families with ≥2 members with onset of diabetes ≤45 years. The highest nonparametric linkage (NPL) score, 2.7 (P < 0.01), was observed on chromosome 1p (D1S473/D1S438). Six other regions on chromosomes 3p, 7q, 11q, 18q, 20q, and 21q showed a nominal P value <0.05. Of the EOD subjects in these 29 families, 20% were GAD antibody positive and 68% displayed type 1 diabetes HLA risk alleles (DQB*02 or 0302). Mutations in maturity-onset diabetes of the young (MODY) 1–5 genes and the A3243G mitochondrial DNA mutation were detected by single-strand conformation polymorphism and direct sequencing. To increase homogeneity, we analyzed a subsample of five families with autosomal dominant inheritance of EOD (greater than or equal to two members with age at diagnosis ≤35 years). The highest NPL scores were found on chromosome 1p (D1S438–D1S1665; NPL 3.0; P < 0.01) and 16q (D16S419; NPL 2.9; P < 0.01). After exclusion of three families with MODY1, MODY3, and mitochondrial mutations, the highest NPL scores were observed on chromosomes 1p (D1S438; NPL 2.6; P < 0.01), 3p (D3S1620; NPL 2.2; P < 0.03), 5q (D5S1465; NPL 2.1; P < 0.03), 7q (D7S820; NPL 2.0; P < 0.03), 18q (D18S535; NPL 1.9; P < 0.04), 20q (D20S195; NPL 2.5; P < 0.02), and 21q (D21S1446; NPL 2.2; P < 0.03). We conclude that considerable heterogeneity exists in Scandinavian subjects with EOD; 24% had MODY or maternally inherited diabetes and deafness, and ∼60% were GAD antibody positive or had type 1 diabetes-associated HLA genotypes. Our data also point at putative chromosomal regions, which could harbor novel genes that contribute to EOD.
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| 9. |
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| 10. |
- Lindholm, Eero, et al.
(författare)
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Classifying diabetes according to the new WHO clinical stages.
- 2001
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Ingår i: European Journal of Epidemiology. - 1573-7284. ; 17:11, s. 983-989
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Tidskriftsartikel (refereegranskat)abstract
- Aims/Hypothesis: To test the usefulness of the new WHO criteria for clinical staging of diabetes in the characterization of 1977 diabetic patients. Methods: The following clinical stages were used: patients on diet and/or oral antidiabetic agents 2 years after diagnosis were considered as non-insulin requiring (NIR; n = 711) and patients who required insulin therapy after 1 year as insulin requiring for control (IRC; n = 543). Patients who because of deteriorating hyperglycemia within 1 year required insulin therapy were considered as insulin requiring for survival (IRS; n = 743). Results: The NIR patients had the highest age at onset (52 ± 12 years; mean ± SD), BMI (29.3 ± 5.2 kg/m2) and C-peptide concentrations (median 0.98 nmol/l; interquartile range 0.72–1.31 nmol/l) but the lowest frequency of GAD antibodies (5.5%) compared to the IRC and IRS groups. The IRC group had a high age at onset (49 ± 13 years), BMI (28.0 ± 4.8 kg/m2), frequency of GAD antibodies (16.8%), intermediate C-peptide concentrations (0.56 nmol/l, interquartile range 0.28–0.94), and the highest prevalence of nephropathy (31.5%) and neuropathy (68.1%). The IRS group had the lowest age at onset (23 ± 15 years), BMI (24.2 ± 3.4 kg/m2), C-peptide concentrations (0.05 nmol/l, interquartile range below detection limit 0.01) and highest frequency of GAD antibodies (44.5%). Retinopathy was more common in IRS than in IRC patients (62.1 vs. 43.9%; p < 0.001). Conclusions: The new WHO criteria seem to discriminate three distinct subgroups and thus provide a useful tool for clinical staging. The IRC patients seem to have a more severe disease than the IRS patients, which has not been clearly acknowledged in the etiological classification. However, because of the cross-sectional nature of these data, they need to be confirmed in a prospective study with defined cut-off limits for when insulin should be initiated.
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