Značná část lidských chorob má genetickou příčinu a pro úspěšnou léčbu je často nezbytné přesně určit, která mutace chorobu způsobuje. Identifikace kauzálních mutací však není vždy jednoznačná, a to i tehdy, máme-li k dispozici relevantní sekvence DNA. Moderní celogenomové metody odhalí řadu sekvenčních variant, u kterých není příčinná souvislost s chorobou zřejmá. Mnohé varianty ovlivňují genovou expresi změnou sestřihu pre-mRNA, ale tento efekt nemusí být odhalen, pokud nebylo již dříve prokázáno, že daná oblast obsahuje regulační elementy sestřihu (SRE). Jejich identifikace je proto klíčovým faktorem pro vyhodnocení vlivu takových mutací na vznik choroby. Projekt si klade za cíl lokalizovat funkční SRE a pokusit se nalézt obecná pravidla jejich výskytu v cílových sekvencích. Proto bude provedena systematická experimentální analýza vybraných oblastí genů, které jsou zodpovědné za vznik závažných lidských chorob. Získaná mapa míst náchylných k mutacím vyvolávajícím změny sestřihu bude využita jako pomocný nástroj pro diagnostiku aberantního sestřihu u nově identifikovaných mutací.; Significant proportion of human diseases is genetically determined and successful treatment is dependent on precise diagnosis of causal mutations. However, their identification is not always so unambiguous, although relevant sequence data is available. Modern genomic methods are able to uncover a considerable number of sequence variants with unknown impact on disease. Sequence variants frequently influence the gene expression through alteration of pre-mRNA splicing, but this effect can be hidden, if the splicing regulatory function of mutated regions was not proven in advance. The identification of splicing regulatory elements (SREs) is therefore a crucial step in evaluation of each mutation as potentially pathogenic. The aim of the project is to localize functional SREs and to try to define some rules for their occurrence by performing a systematic experimental analysis of ten regions in genes involved in disease development. Acquired „hot spot“ map of splicing affecting regions should act as an additional tool for diagnostics of aberrant splicing in newly identified gene variants.

• MeSH
• genetická predispozice k nemoci MeSH
• genetické nemoci vrozené genetika   MeSH
• lidé MeSH
• mutace genetika   MeSH
• sestřih RNA genetika   MeSH
• Check Tag
• lidé MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• genetika, lékařská genetika
• NLK Publikační typ
• závěrečné zprávy o řešení grantu AZV MZ ČR

Mutations affecting splicing underlie the development of many human genetic diseases, but rather rarely through mechanisms of pseudoexon activation. Here, we describe a novel c.1092T>A mutation in the iduronate-2-sulfatase (IDS) gene detected in a patient with significantly decreased IDS activity and a clinical diagnosis of mild mucopolysaccharidosis II form. The mutation created an exonic de novo acceptor splice site and resulted in a complex splicing pattern with multiple pseudoexon activation in the patient's fibroblasts. Using an extensive series of minigene splicing experiments, we showed that the competition itself between the de novo and authentic splice site led to the bypass of the authentic one. This event then resulted in activation of several cryptic acceptor and donor sites in the upstream intron. As this was an unexpected and previously unreported mechanism of aberrant pseudoexon inclusion, we systematically analysed and disproved that the patient's mutation induced any relevant change in surrounding splicing regulatory elements. Interestingly, all pseudoexons included in the mature transcripts overlapped with the IDS alternative terminal exon 7b suggesting that this sequence represents a key element in the IDS pre-mRNA architecture. These findings extend the spectrum of mechanisms enabling pseudoexon activation and underscore the complexity of mutation-induced splicing aberrations. KEY MESSAGE: Novel exonic IDS gene mutation leads to a complex splicing pattern. Mutation activates multiple pseudoexons through a previously unreported mechanism. Multiple cryptic splice site (ss) activation results from a bypass of authentic ss. Authentic ss bypass is due to a competition between de novo and authentic ss.

• MeSH
• bodová mutace MeSH
• exony MeSH
• glykoproteiny genetika   MeSH
• introny MeSH
• lidé MeSH
• messenger RNA genetika   MeSH
• místa sestřihu RNA MeSH
• mladiství MeSH
• mukopolysacharidóza II genetika   MeSH
• mutace MeSH
• sestřih RNA MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

Described here is the phenotypical expression of a novel LMNA mutation c.1157 G>T in a Czech patient with an early-onset form of Emery-Dreifuss muscular dystrophy. The mutation predicts aberrant splicing. Now 21 years old, the patient has had slowly progressing muscle dystrophy since the age of one and early contractures of elbows. He is the only family member affected. Even though the dystrophy typically affects the heart as well, in the present case these signs are not yet expressed.

• MeSH
• fenotyp MeSH
• lamin typ A genetika   MeSH
• lidé MeSH
• loketní kloub MeSH
• lordóza genetika   MeSH
• missense mutace MeSH
• mladý dospělý MeSH
• mutační analýza DNA MeSH
• skolióza genetika   MeSH
• svalová dystrofie Emeryho-Dreifussova genetika   MeSH
• věk při počátku nemoci MeSH
• Check Tag
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH
• práce podpořená grantem MeSH

Retinitis pigmentosa (RP) is a hereditary disease affecting tens of thousands of people world-wide. Here we analyzed the effect of an amino acid substitution in the RNA helicase DHX38 (Prp16) causing RP. DHX38 has been proposed as the helicase important for the 2nd step of splicing. We showed that DHX38 associates with key splicing factors involved in both splicing steps but did not find any evidence that the RP mutations changes DHX38 interaction profile with the spliceosome. We further downregulated DHX38 and monitored changes in splicing. We observed only minor perturbations of general splicing but detected modulation of ~70 alternative splicing events. Next, we probed DHX38 function in splicing of retina specific genes and found that FSCN2 splicing is dependent on DHX38. In addition, RHO splicing was inhibited specifically by expression of DHX38 RP variant. Finally, we showed that overexpression of DHX38 promotes usage of canonical as well as cryptic 5' splice sites in HBB splicing reporter. Together, our data show that DHX38 is a splicing factor that promotes splicing of cryptic splice sites and regulate alternative splicing. We further provide evidence that the RP-linked substitution G332D modulates DHX38 splicing activity.

• MeSH
• DEAD-box RNA-helikasy * genetika   MeSH
• lidé MeSH
• místa sestřihu RNA MeSH
• mutace MeSH
• retinopathia pigmentosa * genetika   MeSH
• sestřih RNA MeSH
• sestřihové faktory * genetika   MeSH
• spliceozomy metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) gene but the association between mutation (genotype) and disease presentation (phenotype) is not straightforward. We have been investigating whether variants in the CFTR gene that alter splicing efficiency of exon 9 can affect the phenotype produced by a mutation. A missense mutation, R117H, which has been observed in three phenotypes, was found to occur on two chromosome backgrounds with intron 8 variants that have profoundly different effects upon splicing efficiency. A close association is shown between chromosome background of the R117H mutation and phenotype. These findings demonstrate that the genetic context in which a mutation occurs can play a significant role in determining the type of illness produced.

• MeSH
• běloši genetika   MeSH
• černoši genetika   MeSH
• cystická fibróza etnologie   genetika   MeSH
• DNA MeSH
• etnicita genetika   MeSH
• fenotyp MeSH
• genotyp MeSH
• introny MeSH
• lidé MeSH
• membránové proteiny * genetika   MeSH
• molekulární sekvence - údaje MeSH
• mutace * MeSH
• protein CFTR MeSH
• sekvence nukleotidů MeSH
• sestřih RNA MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, P.H.S. MeSH

Charcot-Marie-Tooth neuropathy type 1C (CMT1C) is an autosomal dominant demyelinating peripheral neuropathy caused by missense mutations in the small integral membrane protein of lysosome/late endosome (SIMPLE) gene. To investigate the prevalence of SIMPLE mutations, we screened a cohort of 152 probands with various types of demyelinating or axonal and pure motor or sensory inherited neuropathies. SIMPLE mutations were found only in CMT1 patients, including one G112S and one W116G missense mutations. A novel I74I polymorphism was identified, yet no splicing defect of SIMPLE is likely. Haplotype analysis of STR markers and intragenic SNPs linked to the gene demonstrated that families with the same mutation are unlikely to be related. The clustering of the G112S, T115N, and W116G mutations within five amino acids suggests this domain may be critical to peripheral nerve myelination. Electrophysiological studies showed that CMT1C patients from six pedigrees (n = 38) had reduced nerve conduction velocities ranging from 7.5 to 27.0m/sec (peroneal). Two patients had temporal dispersion of nerve conduction and irregularity of conduction slowing, which is unusual for CMT1 patients. We report the expression of SIMPLE in various cell types of the sciatic nerve, including Schwann cells, the affected cell type in CMT1C.

• MeSH
• Charcotova-Marieova-Toothova nemoc * genetika   patofyziologie   patologie   MeSH
• jaderné proteiny * analýza   genetika   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mutace * MeSH
• nervus ischiadicus * fyziologie   chemie   patologie   MeSH
• rodokmen MeSH
• senioři MeSH
• transkripční faktory * analýza   genetika   MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, P.H.S. MeSH

Human beta-mannosidosis is an autosomal recessive, lysosomal storage disease caused by a deficiency of the enzyme beta-mannosidase. Unlike the severe clinical manifestation of the disease in ruminants, in which it leads to neonatal death, the human disease phenotype is generally milder. In addition, the phenotypic manifestation among the reported cases of human beta-mannosidosis is variable, even among members of the same family. To understand the molecular basis of the human disease and the mechanisms for such clinical variability, we sequenced the entire coding region of the human beta-mannosidase gene using a combination of cDNA library screening, RT-PCR and 5' rapid amplification of cDNA ends (RACE). The composite cDNA is 3293 nt, consisting of an 87 nt 5'-untranslated region, 2640 nt coding region and 566 nt 3'-untranslated region. The gene was localized to human chromosome 4q22-25. Analysis of a multiple tissue northern blot demonstrated a single 3.7 kb transcript. Mutation analysis of a Czech gypsy family with two siblings differently affected with beta-mannosidosis demonstrated a homozygous A-->G transition 2 bp upstream of a splice acceptor site. The associated cryptic splice site activation and exon skipping caused by this mutation resulted in two abnormally spliced mutant mRNA species in both siblings.

• MeSH
• alfa-mannosidóza * genetika   MeSH
• beta-mannosidasa MeSH
• komplementární DNA analýza   genetika   MeSH
• lidé MeSH
• mannosidasy * genetika   MeSH
• molekulární sekvence - údaje MeSH
• mutace * MeSH
• sekvence aminokyselin MeSH
• sekvence nukleotidů MeSH
• sekvenční analýza MeSH
• sekvenční seřazení MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, P.H.S. MeSH

Tooth agenesis is one of the most common developmental anomalies in humans. To date, many mutations involving paired box 9 (PAX9), msh homeobox 1 (MSX1), and axin 2 (AXIN2) genes have been identified. The aim of the present study was to perform screening for mutations and/or polymorphisms using the capillary sequencing method in the critical regions of PAX9 and MSX1 genes in a group of 270 individuals with tooth agenesis and in 30 healthy subjects of Czech origin. This screening revealed a previously unknown heterozygous g.9527G>T mutation in the PAX9 gene in monozygotic twins with oligodontia and three additional affected family members. The same variant was not found in healthy relatives. This mutation is located in intron 2, in the region recognized as the splice site between exon 2 and intron 2. We hypothesize that the error in pre-mRNA splicing may lead to lower expression of PAX9 protein and could have contributed to the development of tooth agenesis in the affected subjects.

• MeSH
• anodoncie genetika   MeSH
• dítě MeSH
• dvojčata monozygotní genetika   MeSH
• exony genetika   MeSH
• genetická variace genetika   MeSH
• guanin MeSH
• heterozygot MeSH
• introny genetika   MeSH
• kohortové studie MeSH
• lidé MeSH
• místa sestřihu RNA genetika   MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mutace genetika   MeSH
• nemoci u dvojčat genetika   MeSH
• nepřekládané oblasti genetika   MeSH
• otevřené čtecí rámce genetika   MeSH
• plošný screening MeSH
• polymorfismus genetický genetika   MeSH
• thymin MeSH
• transkripční faktor MSX1 genetika   MeSH
• transkripční faktor PAX9 genetika   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

Severe 5,10-methylenetetrahydrofolate reductase (MTHFR) deficiency is caused by mutations in the MTHFR gene and results in hyperhomocysteinemia and varying severity of disease, ranging from neonatal lethal to adult onset. Including those described here, 109 MTHFR mutations have been reported in 171 families, consisting of 70 missense mutations, 17 that primarily affect splicing, 11 nonsense mutations, seven small deletions, two no-stop mutations, one small duplication, and one large duplication. Only 36% of mutations recur in unrelated families, indicating that most are "private." The most common mutation is c.1530A>G (numbered from NM_005957.4, p.Lys510 = ) causing a splicing defect, found in 13 families; the most common missense mutation is c.1129C>T (p.Arg377Cys) identified in 10 families. To increase disease understanding, we report enzymatic activity, detected mutations, and clinical onset information (early, <1 year; or late, >1 year) for all published patients available, demonstrating that patients with early onset have less residual enzyme activity than those presenting later. We also review animal models, diagnostic approaches, clinical presentations, and treatment options. This is the first large review of mutations in MTHFR, highlighting the wide spectrum of disease-causing mutations.

• MeSH
• databáze genetické MeSH
• homocystinurie genetika   MeSH
• katalytická doména MeSH
• lidé MeSH
• methylentetrahydrofolátreduktasa (NADPH2) chemie   nedostatek   genetika   metabolismus   MeSH
• modely nemocí na zvířatech MeSH
• mutace * MeSH
• novorozenec MeSH
• novorozenecký screening MeSH
• psychotické poruchy genetika   MeSH
• svalová spasticita genetika   MeSH
• věk při počátku nemoci MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• novorozenec MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

BACKGROUND: Hypertrophic cardiomyopathy with severe left ventricular diastolic dysfunction has been associated with marked exercise intolerance and poor prognosis. However, molecular pathogenesis of this phenotype remains unexplained in a large proportion of cases. METHODS AND RESULTS: We performed whole exome sequencing as an initial genetic test in a large Czech family with 3 males affected by nonobstructive hypertrophic cardiomyopathy with severe left ventricular diastolic dysfunction in end-stage disease. A novel frameshift mutation of four-and-a-half LIM domain 1 gene (FHL1) (c.599_600insT; p.F200fs32X) was detected in these individuals. The mutation does not affect transcription, splicing, and stability of FHL1 mRNA and results in production of truncated FHL1 protein, which is contrary to heart tissue homogenate not detectable in frozen tissue sections of myocardial biopsy of affected males. The identified mutation cosegregated also with abnormal ECG and with 1 case of apical hypertrophic cardiomyopathy in heterozygous females. Although skeletal muscle involvement is a common finding in FHL1-related diseases, we could exclude myopathy in all mutation carriers. CONCLUSIONS: We identified a novel FHL1 mutation causing isolated hypertrophic cardiomyopathy with X-chromosomal inheritance.

• MeSH
• dospělí MeSH
• elektrokardiografie MeSH
• elektronová mikroskopie MeSH
• genetická predispozice k nemoci genetika   MeSH
• geny vázané na chromozom X genetika   MeSH
• hypertrofická kardiomyopatie genetika   metabolismus   patofyziologie   MeSH
• imunohistochemie MeSH
• intracelulární signální peptidy a proteiny genetika   metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mutace * MeSH
• myokard metabolismus   patologie   ultrastruktura   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• proteiny s doménou LIM genetika   metabolismus   MeSH
• rodokmen MeSH
• senioři nad 80 let MeSH
• svalové proteiny genetika   metabolismus   MeSH
• zdraví rodiny MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH