Familial hypercholesterolemia (FH) is the most common autosomal dominant disorder. It is characterized by a decrease in LDL cholesterol catabolism and an early clinical manifestation of ...atherosclerotic vessel damage. The aim of the MedPed (Make early diagnosis to Prevent early deaths) project is an early diagnosis of FH patients in order to profit from early treatment and prevent cardiovascular events. Till November 30, 2016 The Czech National MedPed Database has registered 7,001 FH patients from 5,223 different families that is 17.4 % of expected patients in the Czech Republic considering 1:250 FH prevalence. The improvement in diagnostic accuracy, patient cooperation and above all familial cascade screening is enabled by FH mutation detection using the modern technology of next-generation sequencing. FH still remain undiagnosed even though the Czech Republic is one of the most successful countries with respect to FH detection. The opportunities of international collaboration and experience sharing within international programs (e.g. EAS FHSC, ScreenPro FH etc.) will improve the detection of FH patients in the future and enable even more accessible and accurate genetic diagnostics.
Abstract The pathogenesis of myotonic dystrophy type 2 includes the sequestration of MBNL proteins by expanded CCUG transcripts, which leads to an abnormal splicing of their target pre-mRNAs. We have ...found CCUGexp RNA transcripts of the ZNF9 gene associated with the formation of ribonuclear foci in human skeletal muscle and some non-muscle tissues present in muscle biopsies and skin excisions from myotonic dystrophy type 2 patients. Using RNA-FISH and immunofluorescence-FISH methods in combination with a high-resolution confocal microscopy, we demonstrate a different frequency of nuclei containing the CCUGexp foci, a different expression pattern of MBNL1 protein and a different sequestration of MBNL1 by CCUGexp repeats in skeletal muscle, vascular smooth muscle and endothelia, Schwann cells, adipocytes, and ectodermal derivatives. The level of CCUGexp transcription in epidermal and hair sheath cells is lower compared with that in other tissues examined. We suppose that non-muscle tissues of myotonic dystrophy type 2 patients might be affected by a similar molecular mechanism as the skeletal muscle, as suggested by our observation of an aberrant insulin receptor splicing in myotonic dystrophy type 2 adipocytes.
Inherited neuromuscular disorder (NMD) is a wide term covering different genetic disorders affecting muscles, nerves, and neuromuscular junctions. Genetic and clinical heterogeneity is the main ...drawback in a routine gene‐by‐gene diagnostics. We present Czech NMD patients with a genetic cause identified using targeted next‐generation sequencing (NGS) and the spectrum of these causes. Overall 167 unrelated patients presenting NMD falling into categories of muscular dystrophies, congenital muscular dystrophies, congenital myopathies, distal myopathies, and other myopathies were tested by targeted NGS of 42 known NMD‐related genes. Pathogenic or probably pathogenic sequence changes were identified in 79 patients (47.3%). In total, 37 novel and 51 known disease‐causing variants were detected in 23 genes. In addition, variants of uncertain significance were suspected in 7 cases (4.2%), and in 81 cases (48.5%) sequence changes associated with NMD were not found. Our results strongly indicate that for molecular diagnostics of heterogeneous disorders such as NMDs, targeted panel testing has a high‐clinical yield and should therefore be the preferred first‐tier approach. Further, we show that in the genetic diagnostic practice of NMDs, it is necessary to take into account different types of inheritance including the occurrence of an autosomal recessive disorder in two generations of one family.
Autosomal dominant hypercholesterolemia (ADH), more known as familial hypercholesterolemia (FH), is a lipid metabolism disorder characterized by an elevation in low-density lipoprotein cholesterol ...(LDL-C) and increased risk for cardiovascular disease. In this study, we assessed a spectrum of mutations causing ADH in 3914 unrelated Czech patients with clinical diagnosis of hypercholesterolemia. Samples have been collected within the framework of the MedPed project running in the Czech Republic since 1998. So far we have found 432 patients (11.0 %) with the APOB gene mutation p.(Arg3527Gln) and 864 patients (22.1 %) with the LDLR gene mutation. In 864 probands carrying the LDLR gene mutation, 182 unique allelic variants were detected. We have identified 14 patients homozygous for mutations in the LDLR or APOB genes. We performed function analyses of p.(Leu15Pro) and p.(Gly20Arg) sequence variations.
Summary
Background Epidermolysis bullosa simplex (EBS) is an inherited skin disorder caused by mutations in the keratin 5 (KRT5) and keratin 14 (KRT14) genes, with fragility of basal keratinocytes ...leading to epidermal cytolysis and blistering.
Objectives In this study, we characterized mutations in KRT5 and KRT14 genes in patients with EBS and investigated their possible structure–function correlations.
Materials and methods Mutations were characterized using polymerase chain reaction (PCR) and DNA sequencing. Further, to explore possible correlations with function, the structural effects of the mutations in segment 2B of KRT5 and KRT14 and associated with EBS in our patients, as well as those reported previously, were modelled by molecular dynamics with the aid of the known crystal structure of the analogous segment of human vimentin.
Results We have identified mutations in the KRT5 and KRT14 genes in 16 of 23 families affected by EBS in the Czech Republic. Eleven different sequence variants were found, of which four have not been reported previously. Novel mutations were found in two patients with the EBS‐Dowling–Meara variant (EBS‐DM) KRT14‐p.Ser128Pro and KRT14‐p.Gln374_Leu387dup(14) and in three patients with localized EBS (KRT14‐p.Leu136Pro and KRT5‐p.Val143Ala). Molecular dynamics studies show that the mutations p.Glu411del and p.Ile467Thr perturb the secondary alpha‐helical structure of the mutated polypeptide chain, the deletion p.Glu411del in KRT14 has a strong but only local influence on the secondary structure of KRT14, and the structural impact of the mutation p.Ile467Thr in KRT5 is spread along the helix to the C‐terminus. In all the other point mutations studied, the direct structural impact was significantly weaker and did not destroy the alpha‐helical pattern of the secondary protein structure. The changes of 3‐D structure of the KRT5/KRT14 dimer induced by the steric structural impact of the single point mutations, and the resulting altered inter‐ and intramolecular contacts, are spread along the protein helices to the protein C‐terminus, but the overall alpha‐helical character of the secondary structure is not destroyed and the atomic displacements induced by mutations cause only limited‐scale changes of the quaternary structure of the dimer.
Conclusions The results of molecular modelling show relationships between patients’ phenotypes and the structural effects of individual mutations.
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