Home About us Contact
|
Home About us Contact | ||
|
|
||
Heterozygous Patients (heterozygous + patient)
Selected AbstractsDynamics, stability and iron-binding activity of frataxin clinical mutantsFEBS JOURNAL, Issue 14 2008Ana R. Correia Friedreich's ataxia results from a deficiency in the mitochondrial protein frataxin, which carries single point mutations in some patients. In the present study, we analysed the consequences of different disease-related mutations in vitro on the stability and dynamics of human frataxin. Two of the mutations, G130V and D122Y, were investigated for the first time. Analysis by CD spectroscopy demonstrated a substantial decrease in the thermodynamic stability of the variants during chemical and thermal unfolding (wild-type > W155R > I154F > D122Y > G130V), which was reversible in all cases. Protein dynamics was studied in detail and revealed that the mutants have distinct propensities towards aggregation. It was observed that the mutants have increased correlation times and different relative ratios between soluble and insoluble/aggregated protein. NMR showed that the clinical mutants retained a compact and relatively rigid globular core despite their decreased stabilities. Limited proteolysis assays coupled with LC-MS allowed the identification of particularly flexible regions in the mutants; interestingly, these regions included those involved in iron-binding. In agreement, the iron metallochaperone activity of the Friedreich's ataxia mutants was affected: some mutants precipitate upon iron binding (I154F and W155R) and others have a lower binding stoichiometry (G130V and D122Y). Our results suggest that, in heterozygous patients, the development of Friedreich's ataxia may result from a combination of reduced efficiency of protein folding and accelerated degradation in vivo, leading to lower than normal concentrations of frataxin. This hypothesis also suggests that, although quite different from other neurodegenerative diseases involving toxic aggregation, Friedreich's ataxia could also be linked to a process of protein misfolding due to specific destabilization of frataxin. [source] Improved virological response to highly active antiretroviral therapy in HIV-1-infected patients carrying the CCR5 ,32 deletionHIV MEDICINE, Issue 4 2007JJ Laurichesse Background Patients heterozygous for the C-C chemokine receptor 5 (CCR5) ,32 deletion spontaneously progress less rapidly to AIDS and death than do wild-type patients. We investigated whether the CCR5 ,32 deletion has an impact on immunological, virological and clinical responses to highly active antiretroviral therapy (HAART) in HIV-1-infected patients. Patients and methods We included in the study 565 HIV-1-infected patients from the French HIV-1 infected cohort with documented date of serconversion (SEROCO)/haemophiliacs HIV-1 infected (HEMOCO) cohorts, who started HAART after 1996. We investigated virological responses to HAART at 6 months (defined as a plasma HIV-1 RNA measurement below the threshold of detection or a 2 log HIV-1 RNA decrease) and at 12 months (defined as a plasma HIV-1 RNA measurement below the threshold of detection) and clinical response to HAART by Kaplan,Meier survival curves, with AIDS and death as outcomes. Results The ,32 heterozygous patients (n=83; 15%) had a better virological response to HAART than wild-type patients (73 vs 53% at 6 months, P=0.01; and 60 vs 44% at 12 months, P=0.01). This better virological response was still observed after adjustment for antiretroviral status (whether or not patients were naļve to antiretroviral therapy), year of HAART initiation, number of new antiretroviral drugs and baseline viral load. There was no statistical difference between heterozygous patients and wild-type patients in terms of survival and AIDS-free survival. Conclusions CCR5 ,32 heterozygous patients were more likely to have a virological response to HAART than wild-type patients at 6 and 12 months. However, this virological response did not produce better immunological and clinical responses. The long-term impact of the ,32 deletion on survival in HIV-1-infected treated patients should be investigated in a meta-analysis. [source] Toll-like receptor-1, -2, and -6 polymorphisms influence disease extension in inflammatory bowel diseasesINFLAMMATORY BOWEL DISEASES, Issue 1 2006Marie Pierik MD Abstract Background: Evidence that a deficient innate immune response toward the bacterial flora of the gut plays a role in the pathogenesis of inflammatory bowel disease (IBD) is growing. This is underscored by the finding of the association between CARD15 variants and Crohn's disease (CD) and D299G in Toll-like receptor (TLR) 4 and IBD. Our aims were to study nonsynonymous polymorphisms in other TLR genes in IBD. Methods: Thirty-five single nucleotide polymorphisms (SNP) in TLR1-10 were identified from public databases. 284 IBD parent-child trios and a second independent cohort of 285 IBD patients and 191 healthy controls were genotyped with polymerase chain reaction-restriction fragment length polymorphisms. Patients were pooled for genotype-phenotype analyses. Results: Although none of the SNPs was involved in disease susceptibility, a number of variants influenced the disease phenotype. A positive association between TLR1 R80T and pancolitis in UC (P = .045, OR [95% CI] 2.844 [1.026-7.844]) was found. The TLR2 R753G SNP was also associated with pancolitis (P = .027, OR [95% CI] 4.741 [1.197-18.773]). The relative risks for heterozygous patients to develop pancolitis were 5.8 and 3.3 for R80T and R753G, respectively. There was a negative association between TLR6 S249P and ulcerative colitis with proctitis only (P = .026, OR [95% CI] 0.223 [0.096-0.705]). In CD, we found a negative association between ileal disease involvement and TLR1 S602I (P = .03, OR [95% CI] 0.522 [0.286-0.950]). Conclusion:TLR2 and its cofactors TLR1 and TLR6 are involved in the initial immune response to bacteria by recognizing peptidoglycan. An association between nonsynonymous variants in the TLR1, - 2, and - 6 genes and extensive colonic disease in UC and CD was found. Our findings further highlight the role of an abnormal innate immune response in the pathogenesis of IBD. [source] Iron-overload and genotypic expression of HFE mutations H63D/C282Y and transferrin receptor Hin6I and BanI polymorphism in German patients with hereditary haemochromatosisINTERNATIONAL JOURNAL OF IMMUNOGENETICS, Issue 3 2000R. Gottschalk Gene variations of HFE, a HLA-class I like molecule, are highly associated with hereditary haemochromatosis (HH). Functional as well as molecular studies of the HFE protein have indicated that the molecule is involved in iron metabolism and that the HFE gene variations observed among HH patients affect its interaction with the transferrin receptor (TfR). In the present study, we have therefore analysed the relationship between the HFE gene variants, C282Y and H63D, and body iron status among 85 German HH patients. In addition, two TfR gene polymorphism, TfR-Hin6I and TfR-BanI, were typed that have been reported to define ethnically distinct haplotypes. As controls we used 251/159 healthy German blood donors. Seventy-eight (92%) patients were C292Y homozygous, the H63D mutation was present in five (6%) patients with none of the patients being H63D homozygous. Serum transferrin, transferrin saturation and liver iron content were determined prior to therapeutic intervention. Among C282Y homozygous patients serum ferritin levels (2294 ± 3174 vs. 463 ± 224 µg L,1, P < 0.0001) and transferrin saturation (86 ± 18% vs. 62 ± 25%, P = 0.048) were elevated significantly compared with C282Y and/or H63D heterozygous patients. In addition, the liver iron content (291 ± 165 vs. 138 ± 95 µmol g,1, P = 0.028) and liver iron index (6.4 ± 2.8 vs. 3.2 ± 2.3, P = 0.019) were increased among C282Y homozygotes compared with C282Y heterozygotes. In contrast, no difference was observed between patients and controls regarding the distribution of TfR- Hin6I and TfR- BanI alleles. These data indicate that the iron intake is higher among C282Y homozygous patients compared with C282Y heterozygous or C282Y/H63D compound heterozygous individuals and supports the functional role of the HFE protein in iron metabolism whereas the TfR gene variants seem to have no influence on iron uptake. [source] Gender-dependent association of the GNAS1 T393C polymorphism with early aseptic loosening after total hip arthroplastyJOURNAL OF ORTHOPAEDIC RESEARCH, Issue 12 2008Hagen S. Bachmann Abstract The G-protein G,s is involved in the physiology and pathophysiology of bone. Especially, G,s is a key regulator of interleukin-6, which is a potent promoter of aseptic loosening. We hypothesized that the common single nucleotide polymorphism GNAS1 T393C could also affect time to aseptic loosening. Caucasian patients were genotyped for the GNAS1 T393C polymorphism. Time and median time to aseptic loosening were analyzed for dependency on GNAS1 genotypes. Time and median time were not significantly associated with genotypes. Additional analysis corrected for gender revealed, that the TT genotype was associated with significantly longer time (p,=,0.048) as well as median time (p,=,0.022) to aseptic loosening in female patients. In contrast to the findings in females, male TT genotype carriers had significantly shorter time (p,=,0.018) and median time (p,=,0.023) to aseptic loosening. Compared with TT genotype carriers heterozygous patients had a 6.25-fold lower risk with a hazard ratio of 0.160 (p,=,0.016) and male patients carrying the CC genotype had an 11-fold lower risk with a hazard ratio of 0.088 (p,=,0.006) in multivariate analysis. The present study suggests a significant gender-dependent role of the T393C polymorphism in aseptic loosening. The apparently contradictory results in women and men and the finding that the GNAS1 T393C genotype is an independent factor for time to aseptic loosening in male patients assigned this polymorphism as an interesting target for further investigations in bone diseases. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res [source] Liver pathology in compound heterozygous patients for hemochromatosis mutationsLIVER INTERNATIONAL, Issue 4 2002Maximilian Schöniger-Hekele Abstract: Background: While hepatic pathology of homozygous carriers of the C282Y mutation of the HFE haemochromatosis gene is well defined, the impact of the C282Y/H63D compound heterozygous carrier state is unknown. Aims: To evaluate the range of hepatic pathology in C282Y/H63D compound heterozygous patients. Patients: 25 C282Y/H63D compound heterozygous patients with and without known underlying liver disease underwent liver biopsies for evaluation or abnormal liver tests. Eleven cadaveric liver donors with HFE wild type served as controls. Methods: Mutations in the HFE gene were detected by polyacrylamide gel electrophoresis (PAGE) separation of digested polymerase chain reaction (PCR)-amplificates. The extent of light microscopic changes of liver architecture were studied on haematoxylin, eosin (H. E.) stains. In addition, the extent and the distribution of iron deposition was graded on Prussian blue-stained sections and hepatic iron was quantified by atom absorption spectroscopy. Serum ferritin concentration and the transferrin saturation index were measured using routine laboratory methods. Results: Patients without underlying liver disease (n = 15): Hepatic inflammation was seen in only 8% but fibrosis was found in 36% of compound heterozygous patients. Eighty six percent of those patients had stainable iron predominantly found in Rappaport's zone 1 and 2, but all had a liver iron-index < 1.9. Transferrin saturation was found elevated in 36% of compound heterozygous patients. Patients with liver fibrosis showed significantly higher ferritin levels than patients without liver fibrosis (1110 ng/mL versus 307 ng/mL, p < 0.05). Patients with underlying disease (n = 10): In compound heterozygous patients, 77% had hepatic inflammation and 88% fibrosis. Stainable iron (44%) was less frequently found than in patients without underlying liver disease. Hepatic iron-index in patients with underlying liver disease was always below 1.17; transferrin saturation was elevated in only 22% of the compound heterozygous patients. Histologic hepatic iron-index was significantly lower in patients with underlying disease (median 0.047) as compared to patients without underlying liver disease (median 0.274, P < 0.05). Conclusions: The underlying liver disease determines the extent of hepatic pathology seen in livers of compound heterozygous patients. However, considerable histologic fibrosis can also be found in compound heterozygous patients without underlying liver disease. [source] Monitoring neutrophil engraftment in allogeneic stem cell transplantation by flow cytometric analysis of neutrophil-specific antigens NA1 and NA2BRITISH JOURNAL OF HAEMATOLOGY, Issue 2 2007Takeshi Inukai Summary Neutrophil-specific antigen (NA) expression on neutrophils was analysed in 18 Japanese children before and after allogeneic stem cell transplantation (allo-SCT) with myeloablative regimen. Donor,recipient NA-incompatibility was present in one of eight NA1/NA2 heterozygous patients and eight of 10 NA1/NA1 or NA2/NA2 homozygous patients. After allo-SCTs from NA-incompatible donors, a neutrophil recipient-to-donor conversion was confirmed in all cases. Conversion to donor NA type was complete before the absolute neutrophil count reached 0·1 × 109/l. These observations indicate that flow cytometric analysis of NA antigens is a simple and useful method for monitoring neutrophil engraftment in NA-incompatible allo-SCT. [source] | ||||||||||