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The investigated intronic CAPN3 variant NM_000070.3:c.1746-20C>G occurs in the Central and Eastern Europe with a frequency of >1% and there are conflicting interpretations on its pathogenicity. We collected data on 14 patients carrying the CAPN3 c.1746-20C>G variant in trans position with another CAPN3 pathogenic/likely pathogenic variant. The patients compound heterozygous for the CAPN3 c.1746-20C>G variant presented a phenotype consistent with calpainopathy of mild/medium severity. This variant is most frequent in the North/West regions of Russia and may originate from that area. Molecular studies revealed that different splicing isoforms are produced in the muscle. We hypothesize that c.1746-20C>G is a hypomorphic variant with a reduction of RNA and protein expression and only individuals having a higher ratio of abnormal isoforms are affected. Reclassification of the CAPN3 variant c.1746-20C>G from variant with a conflicting interpretation of pathogenicity to hypomorphic variant explains many unidentified cases of limb girdle muscular dystrophy R1 calpain 3-related in Eastern and Central Europe.

Pletencove svalove dystrofie (LGMD, Limb-Girdle Muscular Dystrophies) jsou klinicky a geneticky heterogenni skupinou onemocněni. Doposud bylo identifikovano 29 genů asociovaných s LGMD, ktere rozděluji LGMD do 29 subtypů. Asi 10 % LGMD ma dominantni typ dědicnosti, 90 % LGMD recesivni typ dědicnosti. Jednotlive subtypy LGMD nesdileji spolecný patofyziologický mechanismus onemocněni, který by je odlisoval od jiných forem svalových dystrofii. Pravě naopak LGMD jsou asociovany s geny, jejichž proteinove produkty maji různou funkci a buněcnou lokalizaci. Molekularně geneticka diagnostika LGMD je vzhledem k množstvi asociovaných genů poměrně komplikovaný proces, který je v soucasne době založen na technikach sekvenovani nove generace (NGS, Next-Generation Sequencing) jak na urovni panelu vybraných genů, tak na urovni exomu.

Congenital ichthyoses are a very heterogeneous group of diseases manifested by dry, rough and scaling skin. In all forms of ichthyoses, the skin barrier is damaged to a certain degree. Congenital ichthyoses are caused by various gene mutations. Clinical manifestations of the individual types vary as the patient ages. Currently, the diagnosis of congenital ichthyoses is based on molecular analysis, which also allows a complete genetic counseling and genetic prevention. It is appropriate to refer the patients to specialized medical centers, where the cooperation of a neonatologist, a pediatric dermatologist, a geneticist and other specialists is ensured.

The primary goal was to determine the yield of next-generation sequencing (NGS) epilepsy gene panels used for epilepsy etiology diagnosing using a multidisciplinary approach and to demonstrate the importance of genotype-phenotype correlations. The secondary goal was to evaluate the application of precision medicine in selected patients.This single-center retrospective study included a total of 175 patients (95 males and 80 females) aged 0-19 years. They were examined between 2015 and 2020 using an NGS epilepsy gene panel (270 genes). A bioinformatic analysis was performed including copy number variation identification. Thorough genotype-phenotype correlation was performed.Out of 175 patients, described pathogenic variants or novel variants with clear pathogenic impact were identified in 30 patients (17.14%). Genotype-phenotype correlations and parental DNA analysis were performed, and genetic diagnosis was confirmed on the basis of the results in another 16 out of 175 patients (9.14%). The diagnostic yield of our study increased from 30 to 46 patients (by 53.33%) by the precise genotype-phenotype correlation.We emphasize a complex genotype-phenotype correlation and a multidisciplinary approach in evaluating the results of the NGS epilepsy gene panel, which enables the most accurate genetic diagnosis and correct interpretation of results.

Neuromuscular diseases (NMDs) are a clinically and genetically heterogeneous group of diseases. Currently, 608 genes associated with different types of NMD have been identified. Most of these diseases are rare with a very low prevalence. Advance in the identification of genes associated with NMD can be attributed to technological development in an area of next generation sequencing (NGS) and the affordability of this methodical approach. NGS applications can be divided into analysis of (a) a selected set of genes, (b) an exom, and (c) a genome. The identification of pathogenic variants leads to a significant shift in the understanding of the etiopathogenesis of the disease, allows the prediction of the course of the disease, or its targeted treatment, which may be specific for individual types of NMD or even for particular pathogenic sequence variants.

Dědicna svalova onemocněni jsou vzacna onemocněni vyznacujici se velkou klinickou a genetickou heterogenitou. Rozvojmolekularně genetických metod, zejm. masivni paralelni sekvenace, vede k rozsiřeni znalosti o jejich genetických přicinacha etiopatogenezi, což umožňuje predikci průběhu onemocněni, event. jeho cilenou lecbu.

Dilatacni a hypertroficke kardiomyopatie, poruchy srdecniho rytmu nebo kombinace obojiho mohou patřit do obrazu některých dědicných a/nebo ziskaných chorob kosterniho svalstva. Na tyto sirsi souvislosti může upozornit jednoduche, siroce dostupne vysetřeni serove kreatininkinazy. Pacienti se suspekci na myopatii s kardiomypatii by měli být odeslani k dosetřeni neurologům. Specializovaným laboratornim vysetřenim sera, elektromyograficky, svalovou biopsii a genetickým vysetřenim jsme schopni detekovat ziskane ci dědicne důvody postiženi kosterniho a srdecniho svalsta. Rozpoznani přiciny kardialniho selhani je důležite ke stanoveni komplexniho lecebneho postupu u nemocných i podchyceni rizik život ohrožujici kardiomyopatie u jejich potomků. Uvadime osm kratkých kazuistik myopatie s kardiomyopatii. Cilem prace je upozornit na průsecik nasich odbornosti, seznamit kardiologickou odbornou veřejnost s jednoduchým navodem, jak odhalit myopatii a možnostmi neurologů stran jejiho dosetřeni.

Dědicne ichtyozy patři ke vzacným onemocněnim. Jde o velmi heterogenni skupinu onemocněni projevujici se suchou, hruboua deskvamujici kůži. U vsech forem ichtyoz je v různem rozsahu porusena kožni bariera. Vrozene ichtyozy jsou způsobenymutacemi různých genů. Klinicke projevy jednotlivých typů ichtyoz se v průběhu věku pacienta měni. Jednim z nejzavažnějsichtypů ichtyoz je Harlequin ichtyoza. Autoři popisuji necekane komplikace vznikle po alimentarni chybě, ktere nakonec vedly ažk těžke hepatopatii, ktera vyžadovala lecbu ve specializovanem centru.

Background Extensive genetic screening results in the identification of thousands of rare variants that are difficult to interpret. Because of its sheer size, rare variants in the titin gene (TTN) are detected frequently in any individual. Unambiguous interpretation of molecular findings is almost impossible in many patients with myopathies or cardiomyopathies. Objective To refine the current classification framework for TTN-associated skeletal muscle disorders and standardize the interpretation of TTN variants. Methods We used the guidelines issued by the American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology (AMP) to re-analyze TTN genetic findings from our patient cohort. Results We identified in the classification guidelines three rules that are not applicable to titin-related skeletal muscle disorders; six rules that require disease-/gene-specific adjustments and four rules requiring quantitative thresholds for a proper use. In three cases, the rule strength need to be modified. Conclusions We suggest adjustments are made to the guidelines. We provide frequency thresholds to facilitate filtering of candidate causative variants and guidance for the use and interpretation of functional data and co-segregation evidence. We expect that the variant classification framework for TTN-related skeletal muscle disorders will be further improved along with a better understanding of these diseases.

The low density lipoprotein receptor (LDLR) is a transmembrane protein that plays a key role in cholesterol metabolism. It contains 860 amino acids including a 21 amino acid long signal sequence, which directs the protein into the endoplasmic reticulum. Mutations in the LDLR gene lead to cholesterol accumulation in the plasma and results in familial hypercholesterolemia (FH). Knowledge of the impact of a mutation on the LDLR protein structure and function is very important for the diagnosis and management of FH. Unfortunately, for a large proportion of mutations this information is still missing. In this study, we focused on the LDLR signal sequence and carried out functional and in silico analyses of two sequence changes, p.(Gly20Arg) and p.(Leu15Pro), localized in this part of the LDLR. Our results revealed that the p.(Gly20Arg) change, previously described as disease causing, has no detrimental effect on protein expression or LDL particle binding. In silico analysis supports this observation, showing that both the wt and p.(Gly20Arg) signal sequences adopt an expected α-helix structure. In contrast, the mutation p.(Leu15Pro) is not associated with functional protein expression and exhibits a structure with disrupted a α-helical arrangement in the signal sequence, which most likely affects protein folding in the endoplasmic reticulum.

Epidermolysis bullosa (EB) is a heterogeneous group of inherited skin disorders characterized by blister formation. Classification of patients with EB begins with their separation into one of the four major EB groups, based on the level to which blisters develop: EB simplex (EBS), junctional EB (JEB), dystrophic EB (DEB) and Kindler syndrome. The next level of subclassification takes into account the clinical features present in a given patient, most notably the distribution and severity of cutaneous and extracutaneous disease involvement.

Syndrom Dravetove (DS) patři mezi meně caste progresivni geneticky podminěne epilepsie. Typický je rozvoj v prvnim roce života u dosud normalně se vyvijejicich děti. Inicialně se objevuji generalizovane nebo unilateralni konvulsivni zachvaty, casto vazane na febrilni infekty. Zasadni je odliseni DS od obvyklých febrilnich zachvatů již v inicialni fazi onemocněni. V batolecim věku se přidavaji dalsi typy zachvatů (atypicke absence, myoklonicke zachvaty, parcialni komplexni ci generalizovane tonicko- -klonicke zachvaty) a dochazi k rozvoji psychomotoricke deteriorace. Definitivnim potvrzenim diagnozy je geneticke vysetřeni. V terapii se uplatňuje předevsim valproat, klobazam a stiripentol. Farmakorezistence je typicka. Mezi nefarmakologicke možnosti terapie patři ketogenni dieta a event. implantace vagoveho stimulatoru. Prognoza onemocněni je zavažna.

Hajdu-Cheney syndrome (HCS) is a rare multi-system disease with autosomal dominant inheritance and skeletal involvement, resulting mostly in craniofacial dysmorphy with mid-face hypoplasia, dental anomalies, short stature, scoliosis, shortening of the digits and nail beds, acro-osteolysis and osteoporosis. We report the progression of clinical and radiographic findings in five patients with Hajdu-Cheney syndrome from two families. A custom capture array designed to capture exons and adjacent intron sequences of 230 selected genes were used for molecular analyses, and the pathogenic variants identified were confirmed by PCR and Sanger sequencing. In both families we observed age-dependent changes in the disease, with a progression of pain in older patients, a shortening of digits and nail beds on both the hands and feet, kyphoscoliosis and the persistence of Wormian bones in lambdoid sutures. Molecular analyses performed in two patients revealed that they are heterozygotes for a c.6255T>A (p.Cys2085*) variant in the NOTCH2 gene, resulting in a premature stop-codon. Bone mineral density (Z-score < –2) did not improved in a girl treated with calcium and vitamin D supplementation during childhood and bisphosphonate during adolescence. Hajdu-Cheney syndrome is a slowly progressive disease with a frequently unfavourable prognosis in elderly patients, especially for the development of dental anomalies, osteoporosis and the progression of skeletal complications requiring orthopedic surgeries.

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.

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.

Familial hypercholesterolemia (FH) is the most frequent autosomal dominant hereditary disease which is characterized by a decreased LDL-cholesterol catabolism and early clinical manifestation of atherosclerosis affecting blood vessels. The MedPed (Make early diagnosis to Prevent early deaths) project aims to diagnose patients with FH as early as possible, so that they can profit the most from a therapy started in a timely manner and avoid premature cardiovascular events. Currently, as of 31 October 2016, the Czech national database keeps records of 6 947 patients with FH from 5 223 families. Considering the prevalence of FH equalling 1 : 250, this represents 17.4 % of the overall expected number of patients with FH in the Czech Republic. Determining the mutation responsible for FH, now using a next generation sequencing technology in the Czech Republic, brings with it higher diagnostic accuracy, better cooperation of patients and in particular facilitation of cascade screening in families. Although we are among the most successful countries in the world with regard to FH detection, the majority of patients are still undiagnosed. Moreover, as it turns out, most FH patients do not reach the target values with the current therapeutic possibilities. In this regard the newly approved hypolipidemic drugs, PCSK9 inhibitors, to be hopefully available also in the Czech Republic in the near future for chosen patients with FH at high risk, hold great promise.Key words: cascade screening - familial hypercholesterolemia - LDL-cholesterol - MedPed.

Background: Epidermolysis bullosa simplex associated with muscular dystrophy is a genetic skin disease caused by plectin deficiency. A case of a 19-year-old Czech patient affected with this disease and a review all previously published clinical cases are presented. Main observations: In our patient, skin signs of the disease developed after birth. Bilateral ptosis at the age of 8 years was considered as the first specific symptom of muscular dystrophy. Since then, severe scoliosis, urological and psychiatric complication have quickly developed. The signs of plectin deficiency were found by histopathological studies, electron microscopy and antigen mapping of the skin and muscular samples. Two autosomal recessive mutations in the plectin gene leading to premature termination codon were disclosed by mutation analysis. By review of all published clinical cases, 49 patients with this disease were found. 54 different mutations in the plectin gene were published, p.(Arg2319*) in exon 31 being the most frequently found. Median age of muscular dystrophy development was 9.5 years. Hoarseness and respiratory complications were the most often complications beside skin involvement. Conclusion: Epidermolysis bullosa simplex with muscular dystrophy was diagnosed based on clinical, histopathological (skin and muscle biopsy) and mutation analysis of the plectin gene. Overview of the genetic and clinical characteristic of this disease could be presented by review of all previously published clinical cases. ( J Dermatol Case Rep . 2016; 10(3): 39-48)

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.

Background Hyperphenylalaninemia (HPA) is one of the most common inherited metabolic disorders caused by deficiency of the enzyme phenylalanine hydroxylase (PAH). HPA is associated with mutations in the PAH gene, which leads to reduced protein stability and/or impaired catalytic function. Currently, almost 700 different disease-causing mutations have been described. The impact of mutations on enzyme activity varies ranging from classical PKU, mild PKU, to non-PKU HPA phenotype. Methods We provide results of molecular genetic diagnostics of 665 Czech unrelated HPA patients, structural analysis of missense mutations associated with classical PKU and non-PKU HPA phenotype, and prediction of effects of 6 newly discovered HPA missense mutations using bioinformatic approaches and Molecular Dynamics simulations. Results Ninety-eight different types of mutations were indentified. Thirteen of these were novel (6 missense, 2 nonsense, 1 splicing, and 4 small gene rearrangements). Structural analysis revealed that classical PKU mutations are more non-conservative compared to non-PKU HPA mutations and that specific sequence and structural characteristics of a mutation might be critical when distinguishing between non-PKU HPA and classical PKU mutations. The greatest impact was predicted for the p.(Phe263Ser) mutation while other novel mutations p.(Asn167Tyr), p.(Thr200Asn), p.(Asp229Gly), p.(Leu358Phe), and p.(Ile406Met) were found to be less deleterious.

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.

SH2D1A gene defects are the cause of X-linked lymphoproliferative disorder (XLP-1), a rare condition characterized by severe immune dysregulation. We present a patient lacking the typical symptoms of XLP-1, but experiencing a severe unusual skin condition encompassing features of dermatosclerosis and vesiculobullous skin disease. A maternal cousin of the patient was diagnosed with XLP-1 and found to carry a deletion of the SH2D1A gene. SH2D1A deletion was also identified in our patient, which offered a possible explanation for his skin symptoms. Subsequent analysis showed that the deletion in both cousins was identical and involved the whole SH2D1A gene and a part of the adjacent ODZ1 gene. High phenotypic variability of XLP-1 observed in this family prompted us to analyze the genotype-phenotype correlation of 2 different-sized deletions involving SH2D1A and ODZ1 in 5 patients from 2 families, and we report the clinical and laboratory data on these individuals. Our findings illustrate the wide clinical variability of XLP-1, both inter- and intrafamilial, which may complicate the diagnosis of this condition. The comparison of phenotypes of our patients argues against a strong involvement of the ODZ1 gene in the skin disorder and other symptoms observed in our index patient. His hitherto not described severe skin condition extends the phenotypic range of XLP-1.

Objectives The aim of this study was to determine whether the atherogenic index of plasma (AIP = log[triglycerides/HDL-cholesterol]) differs in heterozygous familial hypercholesterolemia (FH) patients with and without a history of cardiovascular disease (CVD). Design and methods A total of 555 FH patients with known mutations in the LDL receptor or the apolipoprotein B gene, of whom 53 had a history of CVD (CVD + group), were retrospectively analyzed. Results Compared to patients without CVD (CVD − group), CVD + patients showed significantly higher fasting LDL-cholesterol, triglycerides and AIP as well as lower HDL-cholesterol. After both adjustment for age and diabetes and using analysis based on age and sex matched groups, only the increase in triglycerides and AIP in the CVD + vs. the CVD − group remained significant. Conclusion The results of the present study indicate that AIP, which reflects the presence of atherogenic small LDL and small HDL particles, may be connected to the risk of CVD in FH patients.

The aim of this study was to compare HDL-cholesterol and triglyceride levels in patients with familial hypercholesterolemia (FH) with a representative sample of the Czech population.For the FH group: data of 1728 adult patients with FH (600 males and 1128 females) were taken from the MedPed CR database. The control group were 1995 individuals of the population sample of the Czech post-MONICA study (956 males and 1039 females).Compared with controls, FH males showed higher levels of HDL-cholesterol (1.35±0.35 mmol/l vs. 1.31±0.35 mmol/l; P0.05) and triglycerides (1.98±1.00 vs. 1.81±1.45 mmol/l; P0.01). After adjustment for age and BMI, the increase in triglycerides remained significant in the subgroup of non-FDB males only (2.22±0.06 vs. 1.74±0.04 mmol/l; P0.001). Compared with controls, HDL-cholesterol was lower (1.55±0.40 mmol/l vs. 1.65±0.37 mmol/l; P0.001), while triglycerides were higher (1.72±0.82 mmol/l vs. 1.28±0.75, P0.001) in FH females. After adjustment for age and BMI, HDL-cholesterol remained lower in the subgroup of FH females without FDB (1.52±0.01 vs. 1.67±0.01 mmol/l, P0.001) whereas triglycerides were higher in both female subgroups.A lower HDL-C in the group of FH patients compared with control subjects was demonstrated in FH females without FDB only. Elevated triglyceride levels were found in FH males and females, except for males with FDB.

Congenital adrenal hyperplasia (CAH) comprises a group of autosomal recessive disorders caused by an enzymatic deficiency which impairs the biosynthesis of cortisol and, in the majority of severe cases, also the biosynthesis of aldosterone. Approximately 95% of all CAH cases are caused by mutations in the steroid 21-hydroxylase gene (CYP21A2). The CYP21A2 gene and its inactive pseudogene (CYP21A1P) are located within the HLA class III region of the major histocompatibility complex (MHC) locus on chromosome 6p21.3. In this study, we describe chimeric CYP21A1P/CYP21A2 genes detected in our patients with 21-hydroxylase deficiency (21OHD). Chimeric CYP21A1P/CYP21A2 genes were present in 171 out of 508 mutated CYP21A2 alleles (33.8%). We detected four types of chimeric CYP21A1P/CYP21A2 genes: three of them have been described previously as CH-1, CH-3, CH-4, and one type is novel. The novel chimeric gene, termed CH-7, was detected in 21.4% of the mutant alleles. Possible causes of CYP21A1P/CYP21A2 formation are associated with 1) high recombination rate in the MHC locus, 2) high recombination rate between highly homologous genes and pseudogenes in the CYP21 gene area, and 3) the existence of chi-like sequences and repetitive minisatellite consensus sequences in CYP21A2 and CYP21A1P which play a role in promoting genetic recombination.

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.

Duchenne and Becker muscular dystrophies (DMD/BMD) are associated with mutations in the DMD gene. We determined the mutation status of 47 patients with dystrophinopathy without deletion or duplication in the DMD gene by screening performed by reverse transcription-PCR, protein truncation test, and DNA sequencing. We describe three patients with a mutation creating a premature termination codon (p.E55X, p.E1110X, and p.S3497PfsX2) but with a mild phenotype, which present three different ways of rescuing the DMD phenotype. In one patient we detected the insertion of a repetitive sequence AluYa5 in intron 56, which led to skipping of exon 57. Further, using quantitative analysis of DMD mRNA carrying various mutated alleles, we examine levels of mRNA degradation due to nonsense mediated mRNA decay. The quantity of dystrophin mRNA is different depending on the presence of a mutation leading to a premature termination codon, and position of the analysed mRNA region with respect to its 5′ end or 3′ end. Average relative amounts of DMD mRNAs carrying a premature termination codon is 48% and 17%, when using primers amplifying the 5′ and 3′ cDNA regions, respectively.

We report a sporadic case of congenital muscular dystrophy (CMD) in a 13-year-old girl with early manifestation of muscle weakness and hypotonia, severe contractures, bulbar syndrome, progressive external ophtalmoplegia, and white matter changes on magnetic resonance imaging (MRI) of the brain, but no mental defect. Serum creatine kinase (CK) level was normal. Muscle biopsy revealed a dystrophic picture with a prominent inflammatory infiltrate mimicking inflammatory myopathy-typical histological findings in CMD. Immunostaining showed normal expression of merosin, alpha and beta-dystroglycans. Mutation analyses of calpain3, dysferlin, and SEPN1 genes were negative. An electron microscopy revealed the accumulation of abnormally enlarged mitochondria located under the sarcolemma. Measurement of respiratory chain enzyme activities did not reveal any biochemical defect and mitochondrial genetic studies, including sequencing of the entire mitochondrial genome, were unremarkable. Phenotypic presentation of our patient is very unusual and differs considerably from other CMD variants.

We report a 24-year-old male with an unusual combination of two inherited neuromuscular disorders--Charcot-Marie-Tooth (CMT) disease type 1A and Duchenne muscular dystrophy (DMD). A phenotypic presentation of this patient included features of both these disorders. Nerve conduction studies revealed demyelinating peripheral neuropathy. Electromyography showed a profound myogenic pattern. The serum creatine kinase level was highly elevated. Muscle biopsy revealed a dystrophic picture with deficient dystrophin immunostaining. CMT1A duplication on chromosome 17p11.2 was found. The frame-shift mutation c.3609-3612delTAAAinsCTT (p.K1204LfsX11) was detected in the dystrophin gene by analysing mRNA isolated from the muscle tissue. The patient inherited both these mutations from his mother. The combination of CMT1A and DMD has not been reported as yet.

Autosomal recessive congenital ichthyosis (ARCI) represents a heterogeneous group of disorders of epidermal cornification. Nine genes have been identified to be causative of ARCI, including TGM1 1,2 , ABCA12 3 , NIPAL4 4 , CYP4F22 5 , ALOX12B, ALOXE3 6 , PNPLA1 7 , LIPN 8 , and CERS3 9 . ARCI is rare, with a reported prevalence 1 in 200,000 in European and northern American populations 10 . We started DNA analysis of ARCI in 2012 when PCR-direct sequencing of the TGM1, ALOX12B, ALOXE3, NIPAL4, and CYP4F22 genes was introduced and patients were analysed step by step for mutations in these genes.

Hyperphenylalaninemia (HPA) is one of the most common metabolic disorders. HPA, which is transmitted by an autosomal recessive mode of inheritance, is caused by mutations of the phenylalanine hydroxylase gene. Most mutations are missense and lead to reduced protein stability and/or impaired catalytic function. The impact of such mutations varies, ranging from classical phenylketonuria (PKU), mild PKU, to non-PKU HPA phenotypes. Despite the fact that HPA is a monogenic disease, clinical data show that one PKU genotype can be associated with more in vivo phenotypes, which indicates the role of other (still unknown) factors. To better understand the phenotype–genotype relationships, we analyzed computationally the impact of missense mutations in homozygotes stored in the BIOPKU database. A total of 34 selected homozygous genotypes was divided into two main groups according to their phenotypes: (A) genotypes leading to non-PKU HPA or combined phenotype non-PKU HPA/mild PKU and (B) genotypes leading to classical PKU, mild PKU or combined phenotype mild PKU/classical PKU. Combining in silico analysis and molecular dynamics simulations (in total 3000 ns) we described the structural impact of the mutations, which allowed us to separate 32 out of 34 mutations between groups A and B. Testing the simulation conditions revealed that the outcome of mutant simulations can be modulated by the ionic strength.We also employed programs SNPs3D, Polyphen-2, and SIFT but based on the predictions performed we were not able to discriminate mutations with mild and severe PKU phenotypes.

We report a family with X-linked dominant Charcot-Marie-Tooth disease (CMTX1). Three affected family members are described, who underwent detailed clinical, electrophysiological, molecular genetic, and histopathological studies. A novel isoleucine at position 127 with serine (Ile127Ser) mutation in the gap junction protein beta 1 (GJB1) gene was detected. The electrophysiological findings were consistent with a primary demyelinating neuropathy with secondary axonal loss and support this model of disease progression. All patients having the CMT phenotype and intermediate conduction velocities who are negative for CMT1A duplication/hereditary neuropathy with liability to pressure palsies (HNPP) deletion, and whose family shows a dominant trait without male-to-male transmission, should be screened for CMTX1.

Calpain3 (CAPN3, p94) is a muscle-specific nonlysosomal cysteine proteinase. Loss of proteolytic function or change of other properties of this enzyme (such as stability or ability to interact with other muscular proteins) is manifested as limb girdle muscular dystrophy type 2A (LGMD2A, calpainopathy). These pathological changes in properties of calpain3 are caused by mutations in the calpain3 gene. The fact that the human gene for calpain3 is quite long led us to analyse its coding sequence by reverse transcription-PCR followed by sequence analysis. This study reports nine mutations that we found by analysing mRNA of seven unrelated LGMD patients in the Czech Republic. Three of these mutations were novel, not described on the Leiden muscular dystrophy pages so far. Further, we observed a reduction of dysferlin in muscle membrane in five of our seven LGMD2A patients by immunohistochemical analysis of muscle sections.

Wolfram-like syndrome (WFSL) is a rare autosomal dominant disease characterised by congenital progressive hearing loss, diabetes mellitus, and optic atrophy. The patient was a boy with the juvenile form of diabetes mellitus and findings which clinically matched the symptoms of Wolfram syndrome. At the age of 3 1/4 years, diabetes mellitus was diagnosed in this boy who also had severe psychomotor retardation, failure to thrive, a dysmorphic face with Peters anomaly type 3 (i.e. posterior central defect with stromal opacity of the cornea, adhering stripes of the iris, and cataract with corneolenticular adhesion), congenital glaucoma, megalocornea, severe hearing impairment, a one-sided deformity of the auricle with atresia of the bony and soft external auditory canal, non-differentiable eardrum, missing os incus, hypothyreosis, and nephrocalcinosis. Molecular-genetic examinations revealed a de novo mutation p.(Glu809Lys) in the WFS1 gene. No mutations were detected in the biological parents. The mutation p.(Glu809Lys) in the WFS1 gene is associated with WFSL.