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Angiotensin II type 1 receptor gene polymorphisms in patients with cardiac hypertrophy.

Chronic mechanical stress of the heart secondary to arterial hypertension is a primary cause of left ventricular hypertrophy (LVH). The renin-angiotensin system (RAS) plays an important role in the cardiovascular system, regulating the expression of cardiac hypertrophy, in part, independent of the effects of systemic hypertension. A major component of RAS is angiotensin converting enzyme (ACE), which is upregulated in pressure overload-induced cardiac hypertrophy as well as heart failure. In a recent study, we found that the T allele of the M235T polymorphism of the angiotensinogen gene in sporadic hypertrophic cardiomyopathy (HCM) patients is associated with LVH. The present study was designed to assess the contribution of the polymorphisms of the angiotensin II type 1 receptor (AGT1R A1166C) genes on development of left ventricular hypertrophy. Patients with hypertensive LVH and relatives of HCM without manifesting the disease, showed higher C allele frequency compared to patients with HCM (11.3% vs 4.2%, chi 2 = 5.3, p < 0.05 and 10.5% vs 4.2%, chi 2 = 5.3, p < 0.05, respectively), but healthy controls did not (11.3% vs 7.5%, chi 2 = 1.42, NS and 10.5% vs 7.5%, chi 2 = 1.2, NS). The strong interaction between ACE I/D and AGT1R A1166C gene polymorphisms has been found in groups of relatives of HCM patients; odds ratio associated with ACE D allele was significant in subjects carrying the AGT1R C allele (OR = 7.3, 95% CI 1.6-33.1; chi 2 = 7.9, p < 0.02) compared with healthy subjects. We conclude that the molecular variant of the AGT1R A1166C gene is not contributing to the development of cardiac hypertrophy in hypertensive LVH and HCM patients, whereas carriers of both C and D alleles had a four-fold increase in the odds ratio for family history of HCM without manifesting the disease.

Aged↗

Relationship between the -374T/A RAGE gene polymorphism and angiographic coronary artery disease.

The receptor for advanced glycation end products (RAGE) is thought to play a critical role in diabetic atherosclerosis. Accordingly, a functional -374T/A polymorphism in RAGE gene promoter has been associated with macrovascular complications in type 1 diabetic patients. However, the extent to which this common variant influences the risk of coronary artery disease (CAD) in the general population remains to be determined. We genotyped the -374T/A RAGE polymorphism in 259 non-diabetic individuals, of whom 175 had angiographically documented coronary artery disease (CAD patients) and 84 had normal coronary angiography (CAD-free control subjects). Homozygosity for the -374A allele was found in 9.7% of the CAD patients versus 22.6% of the CAD-free subjects (p=0.005). By means of a multiple logistic regression analysis, the AA genotype of the -374T/A polymorphism was shown to be independently associated with a reduced risk of CAD (adjusted odds ratio 0.33, 95% CI 0.15 to 0.73; p=0.006). Our observations suggest that the -374T/A polymorphism of the RAGE gene may reduce susceptibility to CAD, thus exerting a protective effect on coronary risk. Future pathophysiological studies may be worthwhile to clarify the mechanisms behind this association.

Adenosine↗

Is tissue-plasminogen activator gene polymorphism a risk factor for venous thromboembolism in every population?

BACKGROUND: Tissue-plasminogen activator is a key protein of fibrinolytic system. In recent years the relation between t-PA, its genetic polymorphisms and arterial or venous thrombosis were investigated in different populations. The aim of this study is to investigate the role of t-PA gene polymorphism in Turkish venous thromboembolism (VTE) patients. METHODS: A case-control study was performed. We investigated the t-PA insertion/deletion (I/D) polymorphism in 93 VTE patients and 146 controls without VTE. Recurrent cases and documented risk factors for PTE were recorded. RESULTS: Cases and controls did not differ with respect to the different t-PA genotypes. The prevalence of I allele was 44.1%, 44.5% in cases and controls respectively (OR = 0.95, 95% CI: 0.78-1.24, p > 0.05). Different t-PA genotypes had no effect on recurrent disease. No gender difference was observed with respect to the different t-PA genotypes. There was no significant difference for genotype frequency between PTE patients with documented risk factors and unprovoked cases. CONCLUSIONS: In conclusion there was no association between t-PA genotype and VTE in this group of Turkish population. It was also found that genotype frequencies for t-PA in both VTE and control subjects seems different from those reported from western part of the world. ABBREVIATED ABSTRACT: The aim of this study is to investigate the role of t-PA gene polymorphism in Turkish VTE patients. We investigated 93 VTE patients and 146 controls without VTE. Cases and controls did not differ with respect to the different t-PA genotypes. The prevalence of I allele was 44.1%, 44.5% in cases and controls respectively (OR = 0.95, 95% CI: 0.78-1.24, p > 0.05). Different t-PA genotypes had no effect on recurrent disease. No gender difference was observed with respect to the different t-PA genotypes. There was no significant difference for genotype frequency between PTE patients with documented risk factors and unprovoked cases. In conclusion there was no association between t-PA genotype and VTE in this group of Turkish population. It was also found that genotype frequencies for t-PA in both VTE and control subjects seems different from those reported from western part of the world.

Base Sequence↗

The role of angiotensin-converting enzyme and apolipoprotein-E gene polymorphisms on lipid compositions in newborn infants with intrauterine growth restriction.

Recent findings suggest that hypertension, dyslipidemia, diabetes mellitus, coronary heart disease are more common in adults who born with intrauterine growth restriction (IUGR). Several studies have shown that polymorphisms in angiotensin-converting enzyme (ACE) and apolipoprotein-E (Apo-E) are effective in developing the insulin resistance and also in increasing the risk of coronary heart disease. In present study, the frequencies of ACE, Apo-E gene polymorphisms, apolipoprotein-B (Apo-B) mutation and lipid compositions were determined in full-term newborn infants with IUGR. Forty-four newborn infants who had completed 36 weeks of gestational age, 24 healthy infants and 20 with IUGR, were taken into the scope of the study. While total cholesterol (TC) and Apo-B concentrations in infants with IUGR was found to be significantly higher than that of the control group (p<0.05), triglyceride (TG), low-density lipoproteins (LDL), high-density lipoproteins (HDL) and Apo-A1 levels were similar (p>0.05). An insertion/deletion (I/D) polymorphism with a significantly increased frequency was observed in the IUGR group (65%) as compared with the control group (33%) (p<0.05). When the distribution of the Apo-E gene polymorphism (E2, E3 and E4) was studied, no difference was found between the IUGR and control groups with respect to frequency. No Apo-B gene mutation was identified in the study groups. In conclusion, we may suggest that I/D polymorphism is responsible, though in part, for the etiology of intrauterine growth restriction. Levels of total cholesterol and Apo-B are elevated in IUGR infants, suggesting a linkage between low birth weight and atherosclerosis.

Apolipoproteins E↗

A case-control study in IL6 and TGFB1 gene polymorphisms and recurrent spontaneous abortion in southern Brazilian patients.

PROBLEM: A high proportion of recurrent spontaneous abortions (RSA) remains unexplained. Cytokine genotyping has been investigated. We studied the relationship between unexplained RSA, IL6 (-174 G-->C) and TGFB1 (+869, T-->C; +915, G-->C) gene polymorphisms. METHOD OF STUDY: The case-control study composed of 57 south Brazilian women, with unexplained RSA and 74 controls carefully matched was performed. Cytokine genotyping was performed by the polymerase chain reaction-sequence specific primer method, using the 'Cytokine Genotyping Tray'. RESULTS: The results showed that the genotypic frequencies did not differ from samples for TGFB1 gene. In relation to IL6 gene polymorphism there was a statistical difference in genotypic distribution between samples (P < or = 0.025). The frequency of the C/C genotype was increased in women with RSA in comparison with the frequency observed in controls: 18% versus 4% (P = 0.01). CONCLUSIONS: This result strengthened the importance of IL6 genotypes in the pathogenesis of RSA of unknown cause in the south Brazilian population.

Abortion, Habitual↗

[Association of coagulation factor V, VII gene polymorphisms with coronary heart disease].

OBJECTIVE: To study the distribution of coagulation factor V(FV), VII(FVII) gene polymorphisms in Chinese Han population and the association of the polymorphisms with coronary heart disease(CHD). METHODS: Genotypes of FV FVII were typed in 234 CHD patients and 210 controls by polymerase chain reaction-restriction fragment length polymorphism. Selected coronary angiography was performed in 234 CHD patients. RESULTS: FVII allelic frequencies of R,Q and H7,H6 were 94.6%, 5.6%, 70.3%, 29.7% and 91.9%, 8.1%, 60.9%, 39.1% in CHD group and control group respectively. Genotype distribution was in accordance with Hardy-Weinberg equilibrium. There was no significant difference in frequencies of allele and genotype in R353Q or HVR4 polymorphisms between CHD group and control group. The distribution of allele and genotype in R353Q was of significant difference between non-myocardial infarction subgroup and myocardial infarction subgroup (chi2 = 4.711, P<0.05, OR=0.37,95% CI: 0.15-0.94). However, HVR4 polymorphism was not found to be of significant difference within two group (chi2 = 0.142, P>0.05). There was no FV Leiden mutation in all the CHD patients and normal controls. CONCLUSION: The Q allele of the R353Q polymorphism of the FVII gene may be a protective factor against myocardial infarction.

Aged↗

Estrogen receptor gene polymorphism, but not estradiol levels, is related to bone density in healthy adolescent boys: a cross-sectional and longitudinal study.

The purpose of the present study was to investigate the influence of estrogen receptor alpha gene polymorphism and estradiol on height and bone density during and after puberty in males. Using the restriction enzymes XbaI and PvuII, the allelic variants XX, Xx, xx, PP, Pp, and pp were identified in 90 Caucasian boys 16.9+/-0.3 yr of age (mean +/- SD). Bone mineral density (BMD; g/cm2) of the total body, head, femoral neck, and lumbar spine was measured using dual-energy x-ray absorptiometry. Volumetric BMD (vBMD; mg/cm3) was estimated for the spine. The XbaI or PvuII genotypes were not related to the levels of estradiol, and the levels of estradiol were not related to BMD (P > 0.05). The xx allelic variant was associated with a higher spine vBMD than the Xx allelic variant (361 vs. 340 mg/cm3, P = 0.04). In a multivariate analysis including pubertal development, physical activity, and body weight, the XbaI genotype independently predicted total body BMD, head BMD, and spine vBMD (P < 0.05). The PvuII genotype independently predicted spine vBMD (pp > PP, P = 0.01). The 20 boys with the PP allelic variant were found to have a greater body height than the other 70 boys (182 cm vs. 179 cm, P = 0.03). At a 2-yr follow-up the XbaI genotype was still independently related to total body BMD, head BMD, and spine vBMD. In conclusion, estrogen receptor gene polymorphism is related to bone density and height during late puberty and at attainment of peak bone density in young men.

Absorptiometry, Photon↗

Risk factor-gene interaction in carotid atherosclerosis: effect of gene polymorphisms of renin-angiotensin system.

The risk factor-gene interaction in carotid atherosclerosis was investigated in 205 community-dwelling healthy subjects aged 50 years or more in Japan. The intima-media thickness (IMT) of the common carotid artery was evaluated by ultrasonography with a 7.5-MHz probe. Gene polymorphisms were determined for each subject with angiotensin-converting enzyme (ACE) insertion/deletion (I/D), angiotensinogen (AGT) M235T, angiotensin II type 1 receptor (AT1R) A1166C, and apolipoprotein E (apoE) genotypes. There was no genotype-specific difference in carotid IMT among any genes examined. Combinations of genotypes did not increase carotid IMT compared with subjects without these genotypes. In the total population, multiple regression analysis showed that age, systolic blood pressure (SBP), sex, and body mass index (BMI) were significantly associated with carotid IMT. However, the association between risk factors and IMT was genotype-specific. Age was significantly associated with IMT in ACE D carriers, but not in subjects with the ACE II genotype. Analysis of covariance adjusted with other risk factors showed that the age-dependent change in IMT was significantly different between subjects with the ACE II genotype and the ACE D carriers (F[1.196] = 4.97; P = 0.027). Similarly, the regression of IMT on SBP was significantly different between AGT TT and AGT MT + MM (F[1.196] = 7.20; P = 0.0079). The regression of IMT on BMI was also significantly different between apo E4 carriers and noncarriers (F[1.196] = 6.78; P = 0.0099). Furthermore, general linear model analysis with risk factors, genotype, and risk factor-genotype interactions revealed that the age*ACE genotype interaction, the SBP*AGT genotype interaction, and the BMI*apoE genotype interaction were significantly associated with IMT. These findings further support the role of risk factor-gene interaction in carotid atherosclerosis.

Aged↗

Gene polymorphisms of the renin-angiotensin-aldosterone system and essential arterial hypertension in childhood.

In order to investigate the contribution of candidate genes in the renin-angiotensin-aldosterone system (RAAS) in pathogenesis of essential arterial hypertension (EAH), the I/D polymorphism of ACE gene, the M235T polymorphism of the angiotensinogen gene, and the angiotensin II type 1 receptor (AGT,R) A1166C gene polymorphism in a group of children with EAH were analyzed. Fifty-scven children, aged 8-19 years. with the diagnosis of EAH were included in the association study and were compared with 57 subjects with normal blood pressure (the control group). Arterial hypertension was defined as systolic/diastolic blood pressure measurements higher than 95 age-gender-height percentile of the adopted reference values. A trend was found towards an association between the M235T angiotensinogen gene polymorphism and EAH in childhood in a dominant model (odds ratio (OR) 2.1; 95% confidence interval (CI) 0.9-5.1; P = 0.077), whereas the authors failed to demonstrate an association between the ACE I/D gene polymorphism, or the A1166C AGT1R gene polymorphism and EAH in childhood. Additionally, evidence was found of interaction between the angiotensinogen-TT genotype and obesity on the risk of EAH in childhood (OR 19.3; 95% CI 1.1-77.3; P = 0.014). In conclusion, the M235T angiotensinogen gene polymorphism is considered alone as well as in interaction with obesity to be risk factors for EAH in childhood.

Adolescent↗

-455G/A beta-fibrinogen gene polymorphism, factor V Leiden, prothrombin G20210A mutation and MTHFR C677T, and placental vascular complications.

Hyperfibrinogenaemia is associated with systemic arterial and venous thromboembolism and therefore may contribute to placental vascular disease associated with obstetric complications. The fibrinogen-raising -455G/A beta-fibrinogen gene polymorphism may enhance the physiological increase in fibrinogen levels during pregnancy and thereby predispose to obstetric complications. This retrospective case-control study looked at the association between the beta-fibrinogen gene polymorphism -455G/A, the hereditary thrombophilic markers factor V Leiden, prothrombin G20210A mutation (PGM) and C677T methylene tetrahydrofolate reductase (MTHFR), and obstetric complications associated with placental vascular disease. The study group (n = 247) comprised 147 women (90 Caucasian) who met the clinical criteria and a control group of 100 parous women (90 Caucasian) with no history of obstetric or medical complications. No significant differences were observed in the -455A allelic frequencies of the patient and normal control groups, with (allelic frequencies, 0.156 and 0.178, respectively; P = 0.5716, chi2 test, odds ratio = 1.17, 95% confidence interval = 0.65-2.13) or without (allelic frequencies, 0.129 and 0.170, respectively; P = 0.2077, chi2 test, odds ratio = 1.38, 95% confidence interval = 0.81-2.35) the exclusion of non-Caucasian women. There was an increased prevalence of factor V Leiden among Caucasian patients compared with normal controls (allelic frequencies, 0.056 and 0.017, respectively; P = 0.048, chi2 test, odds ratio = 0.29, 95% confidence interval = 0.05-1.15) but there were no differences in the prevalences of PGM or MTHFR. These data suggest that factor V Leiden is associated with an increased risk of obstetric complications, but that the -455A allele of beta-fibrinogen, PGM and MTHFR do not appear to be implicated.

3' Untranslated Regions↗

Glucocorticoid receptor gene polymorphisms in ACTH-secreting pituitary tumours.

OBJECTIVE: The inhibitory action of glucocorticoids on the hypothalamic-pituitary axis is disrupted in ACTH-secreting pituitary tumours. The molecular events leading to the development of these tumours and their relative resistance to glucocorticoids are unknown. We investigated the presence of mutations and polymorphisms of the glucocorticoid receptor (GR) gene in corticotropinoma and their possible relationship with the tissue-specific resistance to glucocorticoids. DESIGN AND METHODS: DNA or RNA was extracted from 18 corticotropinomas and the GR gene was amplified by the polymerase chain reaction (PCR) or reverse transcriptase-PCR followed by automated direct sequencing. RESULTS: We did not identify any mutation in the coding region and the exon-intron boundary regions of the GR gene. The polymorphism AAT > AGT at codon 363 (N363S) was found in 17% and the polymorphism AAT > AAC at codon 766 (N766N) in 11% of tumours, both in heterozygous state. The polymorphisms at codons 22 and 23, at introns 3 and 4, and at codon 618, previously described in normal population, were not observed. CONCLUSIONS: Our results show that GR gene mutations are rare and unlikely to contribute to the glucocorticoid resistance observed in corticotropinomas. Polymorphisms in the GR gene might confer a selective advantage to tumorigenesis in corticotropinoma. However, there was no relationship between GR gene polymorphism and clinical presentation, tumour size or surgery outcome, suggesting that tumour growth may not be directly related to alterations of the GR gene structure.

Adenoma↗

Tumor necrosis factor gene polymorphisms in patients with sporadic Parkinson's disease.

We studied promoter region polymorphisms in the tumor necrosis factor (TNF) gene at position -1031, -863, and -857, in 172 Japanese patients with sporadic Parkinson's disease (PD). The frequency of the -1031C allele, a high producer of TNF, increased significantly in early onset PD patients compared with controls. In addition, PD patients with the -1031C allele showed a significantly earlier onset than those without -1031C allele, after stratification of the data by an interleukin-1beta gene polymorphism. Our findings suggest that TNF might have a toxic effect in PD.

Adult↗

Surfactant protein D gene polymorphism associated with severe respiratory syncytial virus infection.

Respiratory syncytial virus (RSV) is the major respiratory tract pathogen in infancy. Host-related differences in susceptibility to severe RSV infection suggest that genetic factors may play a role. In this study, a candidate-gene approach was used to study whether the surfactant protein D (SP-D) gene polymorphism associates with severe RSV infection. DNA samples from 84 infants hospitalized for the treatment of RSV bronchiolitis and 93 healthy controls were analyzed. The controls were matched with the cases on the basis of sex, hospital district, date of birth (+/-2 wk) and gestational age at birth (+/-2 wk). Three biallelic SP-D gene polymorphisms were genotyped. Significant differences were observed in the SP-D allele frequencies for amino acid 11 between the RSV infants and their matched controls. The frequency of the allele coding for Met 11 (p = 0.033) was increased in the severe RSV group. The frequency of the homozygous genotype Met/Met for amino acid 11 was increased in the RSV group relative to the controls, whereas the heterozygous genotype tended to be less frequent among the RSV cases than in the matched controls. Conditional logistic regression analysis was used to study whether the confounders, i.e. smoking and number of children in the family, influence the association between the homozygous SP-D genotype for methionine 11 and the risk of RSV bronchiolitis. The results further confirmed this association (p = 0.028). To our knowledge, the present report provides the first evidence of a specific gene associated with susceptibility to severe RSV infection.

Female↗

The carriage of pro-inflammatory cytokine gene polymorphisms in recurrent pregnancy loss.

PROBLEM: Recurrent pregnancy loss (RPL) affects 2-4% of couples, and remains largely unexplained. Recent studies have examined the role of cytokines in the maintenance of normal pregnancy, which is linked with an increased expression of Th2 cytokines. Overexpression of Th1 cytokines is associated with RPL. Knowing that functional polymorphisms exist for certain cytokines, it has therefore been suggested that women with RPL may have a genetic predisposition to overexpress Th1 cytokines. METHOD OF STUDY: The genes for interleukin-1 beta (IL-1beta) and tumor necrosis factor alpha (TNF-alpha) carry functional gene polymorphisms. In both cases these are biallelic polymorphisms that can be detected by polymerase chain reaction followed by restriction fragment length polymorphism. The aim of this pilot study was to assess whether carriage of the rarer alleles (TNF*2 and IL-1B*2) could act as independent risk factors in recurrent miscarriage. RESULTS: We found an increased incidence in the carriage of TNF*2, more pronounced in those women with two or more miscarriages. Carriage of the IL-1B*2 either alone or in association with TNF*2 was not associated with recurrent miscarriage. CONCLUSION: There may be a role for these cytokine gene polymorphisms in RPL.

Abortion, Habitual↗

[Influence of angiotensin-converting enzyme gene polymorphism on the anti-proteinuria efficacy of angiotensin-converting enzyme inhibitor in Han nationality of southern Sichuan province in China].

OBJECTIVE: To investigate the association between angiotensin-converting enzyme (ACE) gene polymorphism and the reducing urinary protein efficacy of angiotensin-converting enzyme inhibitor (ACEI) in patients with primary chronic glomerulonephritis in Han nationality of southern Sichuan province. METHODS: Ninety-nine primary glomerulonephritis patients with urinary protein were enrolled in this study. They were treated with benazepril for at least 3 months. The ACE gene insertion/deletion(I/D) polymorphisms in intron 16 were determined by PCR. A comparison of the reducing urinary protein efficacy of benazepril was made between the patients with different ACE genotypes. RESULTS: Urinary protein excretion was significantly higher in patients with ACE DD genotype than that in patients with II genotype. After benazepril treatment for 3 months, the rates of urinary protein decline were observed. The rates of reduction of proteinuria in patients with DD genotype and ID genotype were obviously higher than that in patients with II genotype(P<0.05). CONCLUSION: Benazepril could decline the rate of urinary protein excretion in patients with primary chronic glomerulonephritis, and significant relationship was observed between ACE gene polymorphism and the reducing urinary protein efficacy of ACEI.

Adolescent↗

The impact of donor cytokine gene polymorphisms on the incidence of cytomegalovirus infection after kidney transplantation.

Cytomegalovirus (CMV) seronegative recipients of kidneys from CMV seropositive donors are at a high risk of CMV infection after transplantation since viruses in the allograft may reactivate in patients without prior immunity. We hypothesized that the genetic background of the graft has an influence on the incidence of infection. Effects of IL10, IL6 and IFNG gene polymorphisms, known to affect CMV infectivity, were investigated in 71 CMV seronegative recipients of grafts from CMV seropositive cadaver donors. Donor IL10(-1082 AA) genotype reduced the incidence of CMV infection (p=0.031) and CMV episodes in these patients tended to occur later (AA: median 83 days, AG/GG: median 45 days, p=0.072). In multivariate analysis, other explaining factors than the donor IL10(-1082 AA) genotype alone did not improve Cox hazard model (HR=0.3, 95% CI=0.09-0.96, p=0.043). Recipient polymorphisms did not reduce the incidence of CMV infection. We conclude that donor IL10 gene polymorphisms may influence the likelihood of CMV infection in the high risk patients investigated.

Adolescent↗

Frequency of angiotensin-converting enzyme gene polymorphism in Turkish type 2 diabetic patients.

We aimed to investigate the angiotensin-converting enzyme (ACE) gene polymorphism, ACE activity and their associations with diabetic complications in Turkish patients with type 2 diabetes mellitus. A total of 143 patients and 133 controls were screened for ACE gene I/D polymorphism by using polymerase chain reaction. Serum ACE activities were determined spectrophotometrically. There was no significant difference in the distribution of ACE I/D genotypes between patients and controls. The patients with DD genotype had a higher ACE activity than those with ID and II. Hypertensive diabetic patients with DD genotype had higher ACE activities than those with ID and II. There was no significant difference in the distribution of ACE I/D genotypes between patients with and without nephropathy, retinopathy and hypertension except for patients with and without neuropathy. In patients with DD genotype, creatinine clearance correlated with duration of diabetes. The grade of retinopathy was correlated with duration of diabetes in DD and ID genotypes. The highest ACE activity was measured in hypertensive diabetics with DD genotype. ID genotype was suggested to be a risk factor and II was suggested to be protective for diabetic neuropathy. The DD and ID genotypes might be a predictor for the development of retinopathy in relation to duration of diabetes.

Adult↗

HLA-DQA1 and DQB1 gene polymorphisms in type I diabetic patients from central Italy and their use for risk prediction.

Susceptibility to type I diabetes has been shown to be highly correlated with the presence of an amino acid other than Asp at position 57 of the DQ beta-chain (non-Asp57) and also with the presence of an Arg at position 52 of the DQ alpha-chain (Arg52). In this study we analyzed the DQA1 and DQB1 gene polymorphisms in 65 patients from central Italy and 93 randomly selected control subjects. Polymerase chain reaction amplification of DNA encoding the first polymorphic domain of the DQB1 and DQA1 chains was performed, and DQB1 gene polymorphism was evaluated by dot blot analysis using 11 sequence-specific oligonucleotide probes. For DQA1 typing, a new simple procedure based on allele-specific amplification and analysis of heteroduplex DNA molecules formed by the annealing of mismatched allelic strands was used. This technique allows the discrimination of Arg52 and non-Arg52 DQA1 alleles. We then calculated by logistic regression the contribution of these genetic markers to the development of diabetes. Frequencies and odds ratios relative to the amino acid in position 57 of the DQ beta-chain and the amino acid in position 52 of the DQ alpha-chain showed that the highest odds ratio (odds ratio = 161; 95% confidence interval 19-1386) was that of the homozygous combination of the two susceptibility markers (non-Asp57 and Arg52).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗