Variable Number Tandem Repeat (variable + number_tandem_repeat)

Distribution by Scientific Domains

Selected Abstracts

Recovery of normal autologous myelopoiesis after graft rejection following allogeneic bone marrow transplant for agnogenic myeloid metaplasia

Summary Allogeneic hematopoietic transplantation is the only currently available therapy that has the potential to cure agnogenic myeloid metaplasia (AMM) or primary myelofibrosis (PMF). Amelioration of fibrosis and eradication of the abnormal clone is thought to occur through the repopulation of marrow by donor-derived hematopoiesis and graft- vs. -host reaction leading to graft vs. tumor effect. We report here a 50-year-old female with AMM/PMF, conditioned with busulfan and cyclophosphamide, who rejected a single locus (HLA-B) mismatched bone marrow transplant from her daughter, but recovered normal autologous hematopoiesis with disappearance of marrow fibrosis and extramedullary hematopoiesis. Variable number tandem repeats (VNTR) analysis showed a gradual loss of donor-derived hematopoietic cells with recovery of autologous hematopoiesis. This case therefore illustrates that eradication of AMM/PMF in this patient with myeloablative chemotherapy combined with a transient allogeneic effect was sufficient to suppress the abnormal stem cell clone associated with AMM/PMF with subsequent cure. [source]

Dopamine transporter gene (DAT1) VNTR polymorphism in major psychiatric disorders: family-based association study in the Bulgarian population

L. Georgieva
Objective:,A 40-bp variable number tandem repeat in the 3,-UTR of dopamine transporter gene (DAT1) has been examined for association with major psychiatric disorders in several case,control studies. No significant results have been found. We used a new collection of parent,offspring trios to test for association with schizophrenia (SZ), bipolar 1 disorder (BPI) and schizoaffective (SA) disorder. Method:,We genotyped trios from Bulgarian origin where the proband had SZ (178 trios), BPI (77 trios) and SA (29 trios). Alleles ranging from 5 to 11 repeats were observed. The results were analysed with the extended TDT (ETDT). Results:,No preferential transmission of alleles was observed for any diagnostic group. The presence of allele DAT*10 was associated with the severity and frequency of auditory hallucinations, however, this result is not significant if corrected for multiple testing. Conclusion:,Our results are in agreement with previous reports of a lack of association between this polymorphism and major psychiatric disorders. [source]

Additive effect of BDNF and REST polymorphisms is associated with improved general cognitive ability

F. Miyajima
Brain-derived neurotrophic factor (BDNF) is a pleiotropic protein involved in neuronal proliferation, differentiation, synaptic plasticity and survival. Independent studies investigating association between the functional BDNF Val66Met polymorphism and cognitive abilities have reported some conflicting findings, which may reflect inadequate sample size, variation in testing methods, population stratification or the confounding effects of other genes. To test the latter hypothesis, we screened and genotyped polymorphisms in the RE1-silencing transcription factor (REST) gene whose function includes the downregulation of BDNF expression. We identified an exon 4 hexadecapeptide variable number tandem repeat (VNTR) with either four or five copies that was located within a proline-rich domain and investigated a further five single nucleotide polymorphisms (SNPs). Using a cohort of 746 community-dwelling older volunteers, we analysed REST genotype data both independently and in combination with the BDNF Val66Met polymorphism. A haplotype within the REST gene containing the four copy VNTR and a non-synonymous SNP showed a weak but significant association with a higher score of general intelligence (P = 0.05). Analysis of this haplotype and the BDNF Val66Met polymorphism in combination showed a significant interaction (global P -value = 0.0003) with an additive increase in cognitive performance for those possessing the BDNF Val66 allele and the REST haplotype containing the four copy repeat (P = 0.004). The REST haplotypes in combination with the BDNF Met66 polymorphism did not reduce cognitive performance more than the independent influence of the Met66 allele. Our results suggest that investigation of a common REST polymorphism may be necessary to help reduce contrasting reports based around BDNF Val66Met and cognition. [source]

IL-1 receptor antagonist gene polymorphism in idiopathic recurrent spontaneous abortion in a Chinese Han population

M. Z. Dai
Summary Interleukin-1 receptor antagonist (IL-1Ra) has been supposed to play important roles in pregnancy. The purpose of this study was to evaluate the association between the polymorphisms of IL-1Ra gene (IL1RN) variable number tandem repeat (VNTR) in intron 2 with idiopathic recurrent spontaneous abortion (RSA). Ninety-two RSA patients and hundred normal women with at least one live birth and no history of miscarriage were included in the study. Frequencies of the IL1RN alleles and genotypes were determined. Data revealed that the prevalence of IL1RN allele and genotype was not significant between the RSA and control group (all P > 0.05). Our finding indicated that the polymorphism VNTR of IL1RN gene in intron 2 may not be a risk factor for RSA in the Chinese Han population. [source]

Study on VNTR polymorphism of gene IL-1RA in 19 Chinese populations

J. Jiang
Summary Earlier studies suggested that a variable number tandem repeat (VNTR) polymorphism in intron 2 of the interleukin-1 receptor antagonist (IL-1RA) gene might be associated with some chronic inflammatory diseases, autoimmune diseases and solid tumours. To study the distribution of this polymorphism in China, 1352 samples were collected from 19 widely distributed Chinese populations. PCR was used to genotype the VNTR. The overall frequencies of allele 1 and allele 2 were 0.913 and 0.064 respectively. The frequency of the allele 2 was significantly different between the northeastern and the northwestern populations. Moreover, the allele frequencies at this locus in three Chinese Han populations were different from that in minority populations. When compared with other populations worldwide, the frequencies of the two alleles in China were not significantly different from those in the Asian and Pacific Islands. However, the prevalence of allele 1 in China was significantly higher, and the prevalence of allele 2 was significantly lower, than those in American and European Caucasians, and the pairwise Fst values reinforced this observation. The differences of the allele frequencies between different regions and within the same region showed that geography and race have important roles in the population differentiation for the IL-1RA gene. In summary, our results provide a valuable reference for population genetic information and future disease association studies in Chinese populations. [source]

C-reactive protein levels and common polymorphisms of the interleukin-1 gene cluster and interleukin-6 gene in patients with coronary heart disease

G. Latkovskis
Summary C-reactive protein (CRP) is an inflammatory marker associated with increased cardiovascular risk. Production of CRP is regulated by interleukin (IL)-1,, IL-1 receptor antagonist and IL-6. In 160 patients with coronary heart disease (CHD) confirmed by angiography, we examined the relationship between CRP level and five polymorphisms in genes coding for these cytokines: IL-1B(,511), IL-1B(+3954), a variable number tandem repeat (VNTR) polymorphism in intron 2 of IL-1RN [IL-1RN(VNTR)], IL-6(,174) and IL-6(,572). CRP values were logarithmically normalized (log-CRP) for statistical calculations. In univariate analysis, carrier status for the IL-1B(+3954)T allele and IL-1RN(VNTR) allele 2 [IL-1RN(VNTR)*2] correlated with higher (P < 0.01) and lower (P < 0.05) log-CRP values, respectively. Among the potential confounding factors analysed, smoking, body mass index, total cholesterol (P < 0.05 for all) and diabetes (P = 0.056) were positively correlated with CRP level. After adjustment for non-genetic covariates, CRP levels remained significantly (P < 0.01) higher in carriers of IL-1B(+3954)T than in non-carriers: mean log-CRP (with 95% confidence interval) was 0.443 (0.311,0.574) for CT or TT genotypes compared with 0.240 (0.107,0.373) for the CC genotype, which corresponded to back-transformed CRP levels of 2.77 and 1.74 mg l,1, respectively. Adjusted association was also significant for IL-1RN(VNTR)*2 (P < 0.01), with lower CRP levels in the presence of allele 2: the mean log-CRP value was 0.252 (0.115,0.388) for carriers and 0.421 (0.290,0.552) for non-carriers (CRP 1.79 and 2.64 mg l,1, respectively). When alleles of both polymorphisms were entered into the model simultaneously, the association remained significant for IL-1B(+3954)T (P < 0.05), but not for IL-1RN(VNTR)*2. We conclude that IL-1B(+3954)T is associated with higher CRP levels in patients with CHD, and we found that this association was significant after adjustment for major risk factors. Our data also suggest a possible relationship of IL-1RN(VNTR)*2 with lower CRP levels in the same patients. [source]

Age-related change in the association between a polymorphism in the PER3 gene and preferred timing of sleep and waking activities

Summary The objective of this study was to investigate the effect of age on the association between preferred timing of sleep and waking activities and a coding-region variable number tandem repeat (VNTR) polymorphism in the clock gene PER3. We have previously reported this polymorphism to associate with diurnal preference and delayed sleep phase syndrome (DSPS). Participants (n = 1590; 707 males and 883 females) completed the Horne,Östberg (HÖ) questionnaire for diurnal preference and provided a DNA sample. Overall HÖ scores were plotted against age. The 5% extremes and intermediates were selected for genotyping. Frequencies of the PER3 4- and 5-repeat alleles were examined in separate age groups (18,29, 30,39, 40,49 and 50+ years of age). The 4-repeat allele was significantly more frequent in evening types, and the 5-repeat allele more frequent in morning types (Fisher's exact test, P = 0.016). Analysis in the four age groupings revealed that the strength of this association attenuated with age and was significant only in the youngest group (18,29 years). These results extend our previous finding of an association between the PER3 VNTR and diurnal preference. They also demonstrate that diurnal preference in young people is more closely associated with this polymorphism than it is in other age groups. [source]

C677T polymorphism of methylenetetrahydrofolate reductase gene affects plasma homocysteine level and is a genetic factor of late-onset Alzheimer's disease

Tomoyuki KIDA
Abstract Background:, Elevated plasma homocysteine levels are known as a risk for atherosclerotic vascular disease and venous thrombosis and have been shown as a risk for late-onset Alzheimer's disease (LOAD). Method:, To examine the effect of genetic factors predisposing to elevated plasma homocysteine levels on the occurrence of LOAD, we determined the genotype of a C677T polymorphism of methylenetetrahydrofolate reductase (MTHFR) gene and a variable number tandem repeat (VNTR) spanning exon 13,intron 13 boundary of cystathionine ,-synthase (CBS) gene in patients with LOAD and community-based control subjects. Results:, Logistic regression indicated that the MTHFR-T allele was a risk for LOAD (P < 0.05), independently from apolipoprotein E-,4 (APOE-,4) allele. Kaplan,Meier tests showed that in APOE-,4 non-carriers, individuals with the MTHFR-TT genotype have occurences of LOAD earlier than those with the MTHFR-CC genotype (P < 0.05). Multiple regression analysis indicates that MTHFR-T allele increases plasma homocysteine levels (P = 0.0002), while the number of X chromosomes decreases (P = 0.01). Plasma homocysteine level was not correlated with age, plasma albumin reflecting nutritional condition, and the dose of APOE-,4 allele. The CBS-20 VNTR allele showed the same trend to increase plasma homocysteine level as the MTHFR-T allele, but a risk effect for LOAD was not evident. Conclusion:, A genetic propensity for elevated plasma homocysteine levels, explained by the MTHFR-T allele encoding defective enzymatic function, is involved in the development of LOAD, particularly in APOE-,4 non-carriers, and that homocysteine metabolism could be a preventive target to LOAD in the elderly. [source]

Familial monozygotic twinning: A report of seven pedigrees,

Geoffrey Machin
Abstract Seven families contained 19 MZ twin pairs (2.7 pairs/family), diagnosed by low-stringency variable number tandem repeats in DNA from placental tissue or blood. Chorion status was known in 10 pairs, 6 dichorionic, 4 monochorionic. Sex ratio was equal. Autosomal dominant inheritance is apparent. © 2009 Wiley-Liss, Inc. [source]