Ondřej Souček

Autosomal recessive limb-girdle muscular dystrophies in the Czech Republic

BackgroundAutosomal recessive limb-girdle muscular dystrophies (LGMD2) include a number of disorders with heterogeneous etiology that cause predominantly weakness and wasting of the shoulder and pelvic girdle muscles. In this study, we determined the frequency of LGMD subtypes within a cohort of Czech LGMD2 patients using mutational analysis of the CAPN3, FKRP, SGCA, and ANO5 genes.MethodsPCR-sequencing analysis; sequence capture and targeted resequencing.ResultsMutations of the CAPN3 gene are the most common cause of LGMD2, and mutations in this gene were identified in 71 patients in a set of 218 Czech probands with a suspicion of LGMD2. Totally, we detected 37 different mutations of which 12 have been described only in Czech LGMD2A patients. The mutation c.550delA is the most frequent among our LGMD2A probands and was detected in 47.1% of CAPN3 mutant alleles. The frequency of particular forms of LGMD2 was 32.6% for LGMD2A (71 probands), 4.1% for LGMD2I (9 probands), 2.8% for LGMD2D (6 probands), and 1.4% for LGMD2L (3 probands).Further, we present the first results of a new approach established in the Czech Republic for diagnosis of neuromuscular diseases: sequence capture and targeted resequencing. Using this approach, we identified patients with mutations in the DYSF and SGCB genes.ConclusionsWe characterised a cohort of Czech LGMD2 patients on the basis of mutation analysis of genes associated with the most common forms of LGMD2 in the European population and subsequently compared the occurrence of particular forms of LGMD2 among countries on the basis of our results and published studies.

Sequestration of MBNL1 in tissues of patients with myotonic dystrophy type 2

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 CCUG(exp) 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 CCUG(exp) foci, a different expression pattern of MBNL1 protein and a different sequestration of MBNL1 by CCUG(exp) repeats in skeletal muscle, vascular smooth muscle and endothelia, Schwann cells, adipocytes, and ectodermal derivatives. The level of CCUG(exp) 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.

Hypertext atlas of fetal and neonatal pathology

Hypertext atlas of fetal and neonatal pathology is a free resource for pregraduate students of medicine, pathologists and other health professionals dealing with prenatal medicine. The atlas can be found at http://www.muni.cz/atlases. The access is restricted to registered users. Concise texts summarize the gross and microscopic pathology, etiology, and clinical signs of both common and rare fetal and neonatal conditions. The texts are illustrated with over 300 images that are accompanied by short comments. The atlas offers histological pictures of high quality. Virtual microscope interface is used to access the high-resolution histological images. Fetal ultrasound video clips are included. Case studies integrate clinical history, prenatal ultrasonographic examination, gross pathology and histological features. The atlas is available in English (and Czech) and equipped with an active index. The atlas is suitable both for medical students and pathologists as a teaching and reference tool. The atlas is going to be further expanded while keeping the high quality of the images.