Biomedical subjects

G Mátyás

Publications and source records attributed to G Mátyás.

10 recordsLinked to original sources

PubMed2006

Clinical profiles of four patients with Rett syndrome carrying a novel exon 1 mutation or genomic rearrangement in the MECP2 gene.

Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the X-linked MECP2 gene encoding methyl CpG binding protein 2 (MeCP2). Recently, a new isoform of MeCP2 including exon 1 was identified. This new isoform is more abundantly expressed in brain than the isoform including exons 2-4. Very little is known about the phenotypes associated with mutations in exon 1 of MECP2 since only a limited number of RTT patients carrying such mutations have been identified so far. In this study, we screened a cohort of 20 girls with RTT for exon 1 mutations by sequencing and multiplex ligation-dependent probe amplification (MLPA). We identified one girl with a novel exon 1 mutation (c.30delCinsGA) by sequencing and three with genomic rearrangements by MLPA. Comparison of the phenotypes showed that the girls carrying a mutation or rearrangement encompassing exon 1 were more severely affected than the girls with rearrangements not affecting exon 1.

Adolescent↗

PubMed2005

Marfan syndrome--a diagnostic challenge caused by phenotypic and genetic heterogeneity.

OBJECTIVES: Marfan syndrome (MFS) is an autosomal dominant inherited connective tissue disorder caused by mutations in the fibrillin-1 (FBN1) gene with variable clinical manifestations in the cardiovascular, musculoskeletal and ocular systems. METHODS: Data of moleculor genetic analysis and a catalogue of clinical manifestations including aortic elastic parameters were mined in order to (i) assess aortic abnormality before and during medical treatment, and to (ii) identify novel correlations between the genotype and phenotype of the disease using hierarchical cluster analysis and logistic regression analysis. A score measure describing the similarity between a patient's clinical symptoms and a characteristic phenotype class was introduced. RESULTS: A probabilistic model for monitoring the loss of aortic elasticity was built on merely aortic parameters of 34 patients with classic MFS and 43 control subjects showing a sensitivity of 82% and a specificity of 96%. The clinical phenotypes of 100 individuals with classical or suspected MFS were clustered yielding four different phenotypic expressions. The highest correlation was found between FBN1 missense mutations, which manifested as ectopia lentis, skeletal major and skin minor criteria, and two out of four clustered phenotypes. The probability of the presence of a missense mutation in both phenotype classes is approximately 70%. CONCLUSIONS: Monitoring of aortic elastic properties during medical treatment may serve as additional criterion to indicate elective surgical interventions. Genotype-phenotype correlation may contribute to anticipate the clinical consequences of specific FBN1 mutations more comprehensively and may be helpful to identify MFS patients at risk at on early stage of disease.

Adolescent↗

PubMed2002

Genetic variation of oaks ( Quercus spp.) in Switzerland. 3. Lack of impact of postglacial recolonization history on nuclear gene loci.

Quercus petraea, Quercus pubescens and Quercus robur are closely related and interfertile white oaks native to Switzerland. The three species are known to share identical cpDNA haplotypes, which are indicative of the postglacial recolonization history of populations. Only two haplotypes are common in Switzerland. We compared variation of cpDNA and of isozymes in 28 oak populations from Switzerland in order to assess the impact of the postglacial population history on current genetic structures of nuclear controlled isozyme gene loci. Species delineation was based on Principal Component Analysis of leaf morphological traits. The species status of populations was reflected at isozyme gene loci, but differentiation between populations with different cpDNA haplotypes and hence different recolonization history was very low at enzyme gene loci for all species. Thus, glacial and postglacial population history was not reflected at nuclear gene loci on the temporal and spatial scale covered by the present study. Extensive gene flow through pollen among populations is likely to have blurred a previously existing genetic differentiation at biparentally inherited gene loci that possibly evolved in the different glacial refugia of the above mentioned cpDNA haplotypes.

Alleles↗

PubMed2001

Tandem repeats in plant mitochondrial genomes: application to the analysis of population differentiation in the conifer Norway spruce.

Mitochondrial DNA, widely applied in studies of population differentiation in animals, is rarely used in plants because of its slow rate of sequence evolution and its complex genomic organization. We demonstrate the utility of two polymorphic mitochondrial tandem repeats located in the second intron of the nad1 gene of Norway spruce. Most of the size variants showed pronounced population differentiation and a distinct geographical distribution. A GenBank search revealed that mitochondrial tandem repeats occur in a broad range of plant species and may serve as a novel molecular marker for unravelling population processes in plants.

Cycadopsida↗

PubMed1989

[Benzidine and its derivatives in the immunohistochemical analysis of peroxidase].

Authors have studied the application of benzidine and its derivatives for the demonstration of the marker enzyme horseradish peroxidase. Benzidine compounds are known to be in a blueish dimeric form under oxidative circumstances, while after polymerization they yield a dark brown end product. If the dimeric state is stabilized, the 3,3'-dimethoxy benzidine (o-dianisidin) appears to be the most suitable to demonstrate peroxidase. The o-dianisidin reaction has the advantage of high sensitivity and that the end product shows a birefringence in polarized light. Upon mounting with organic media the end product is stable.

Benzidines↗

PubMed1985