[Application of warfarin pharmacogenetics]. / Vyuzití farmakogenetiky pri lécbe warfarinem.

Even with its narrow therapeutic index, interindividual variability in daily dose and possible serious bleeding complications, is warfarin the mainstay of therapy and prevention of thromboembolic disease. The application of pharmacogenetics in testing individual polymorphisms of two genes CYP 2C9 (pharmacokinetics of warfarin) and VKORC1 (sensitivity on warfarin) is promising tactics leading to a safe anticoagulation. The first of two applications of pharmacogenetics is assesment of the daily dose of warfarin for individual patients even before starting the therapy. The second is the risk stratification of already warfarinized patients: The carriers of variant genotype are in a greater risk of bleeding complications. The following article is dedicated to the evaluation of literature and our own laboratory and clinical experience with these applications in clinical practise.

[DNA diagnosis of the fragile X chromosome syndrome--FRAXA using PCR]. / DNA diagnostika syndromu fragilního X chromozomu--FRAXA pomocí PCR.

BACKGROUND: Fragile X syndrome is gonosomal recessive mental retardation with the frequency 1:1000 in male population. Fragile X syndrome is caused by amplification of CGG repeat in 1. exon of FMT-1 gene. The aim of this study was to set up and validate a rapid and efficient PCR diagnosis to select FRAXA negative patients in population of mental retarded patients. METHODS AND RESULTS: In the set up phase of the method, 196 patients were diagnosed. We were using modified radioactive PCR of CGG. Obtained PCR fragments were separated on 6% denaturing PAGE. Results were correlated with Southern blot analysis using pE5.1 probe. STR-PCR was verified on a large set of patients and shows validity and efficiency of results in the case of pre- and full mutations in male hemizygous patients too. For estimation of carriers with pre- and full mutation by females modified diagnostic approach was developed. There was no difference found between results from PCR and Southern blot analysis. CONCLUSIONS: The PCR method is convenient not only for selection of FRAXA negative patients, but for diagnosis of full mutation and premutation of affected probands.

[Use of CA repeat polymorphism in direct and indirect diagnosis of Duchenne and Becker muscular dystrophy]. / Vyuzitie polymorfizmov CA opakovaní v priamej a nepriamej diagnostike Duchenneovej a Beckerovej muskulárnej dystrofie.

BACKGROUND: DNA analysis makes it possible to confirm the clinical diagnosis of the majority of cases DMD/BMD and to detect at the same time carries and the prenatal diagnosis for relatives at risk. The objective of the present work was to improve the haplotype analysis and to identify the most frequent deletions in carries. METHODS AND RESULTS: The method is based on the initial amplification of several DNA polymorphisms of CA repetitions and subsequent identification of alleles in the denaturation sequencing polyacrylamide gel using radioactive detection system. The system of CA polymorphisms provides information in the great majority of families, it detects the recombination in the DMD gene, which reduces to a minimum the risk of a diagnostic error and provides valuable information on the carriership of deletion. CONCLUSIONS: The introduction of haplotype analysis of CA repetitions is beyond doubt an asset to the prenatal diagnosis of DMD/BMD and assessment of carriership of this serious hereditary disease. The variability of the length of alleles of these markers improves analysis, prenatal diagnosis and makes it possible to rule out or identify deletion in cca 40% carriers.