- MeSH
- Fungi immunology pathogenicity MeSH
- Mutation methods MeSH
- Mice MeSH
- Lung Diseases, Fungal etiology immunology MeSH
- Check Tag
- Mice MeSH
V současné době prudce narůstá množství identifikovaných genů, které jsou-li poškozeny nebo je-li změněna jejich funkce či regulační vztahy způsobují dědičnou predispozici k určitému onemocnění. Molekulárně genetická diagnostika je nyní dostupnou součástí vyšetření u řady geneticky podmíněných chorob. Laboratorní metody umožňují detekci široké škály mutací, které lze obecně definovat jako odchylky od specifické DNA sekvence ve srovnání s referenční sekvencí zveřejněnou v genové databázi. V některých případech je však obtížné rozlišit, zda je detekovaná sekvenční varianta hledanou onemocnění způsobující mutací nebo zda se jedná o neutrální (polymorfní) variantu nemající vztah k onemocnění jedince. Dědičné formy komplexních onemocnění, jako jsou například hereditární formy nádorových onemocnění, jsou z hlediska interpretace závažnosti mutace velmi problematickou skupinou. Další analýzy na DNA a na proteinové úrovni s využitím bioinformatiky však mohou míru patogenity sekvenčních variant nejasného významu odhalit. Určení konkrétní příčiny genetické predispozice k onemocnění a míra patogenity za onemocnění odpovědné mutace má význam pro včasný záchyt jedinců ve velkém riziku onemocnění, pro cílená preventivní a léčebná opatření a umožňuje v závažných případech prenatální nebo případně také preimplantační diagnostiku.
Molecular genetic diagnostics is available for increasing number of genetically determined diseases. Awide spectrum of mutations can be detected by laboratory methods. A mutation can be defined as a change in a specific DNA sequence when compared with the reference sequence published in the gene database. However, in some cases it is difficult to distinguish if the detected sequence variant is a causal mutation or a neutral (polymorphic) variation without any effect on phenotype. The interpretation of rare sequence variants of unknown significance detected in disease-causing genes becomes an increasingly important problem. Further analysis on DNA and on protein levels with the use of bioinformatics are needed to reveal the effect of rare sequence variants. Inherited complex disorders, for example rare hereditary forms of cancer diseases, represent a challenge tomolecular geneticists. The identification of exact causal mutation directly responsible for the development of the disease and for the assessment of disease risk resulting from this genetic variation has further implications. Predictive genetic diagnostics allows identify relatives at high risk of genetically determined disease and use of targeted preventive and therapeutic approaches. In severe cases it allows also prenatal or pre-implantation diagnostics.
CBP je transkripční koaktivátor, který je schopen interagovat s mnoha transkripčními faktory. Ovlivňuje trans- kripci řízenou těmito faktory např. prostřednictvím vazby na holoenzym RNA polymerázy II a prostřednictvím acetylace histonů. Mutace genu CBP je příčinou autozomálně dominantního dědičného onemocnění nazývaného Rubinsteinův-Taybiho syndrom, které se vyznačuje mentální a růstovou retardací, typickými obličejovými malfor- macemi a širokými palci u rukou a nohou. Gen CBP může být postižen translokací t(8;16)(p11;p13.3), která vede ke vzniku chimérického proteinu MOZ/CBP a k vývoji akutní myeloblastové leukémie. Následkem terapie založené na využití léků, které inhibují funkci topoizomerázy II, může vzniknout translokace t(11;16)(q23;p13.3), která způsobuje tvorbu chimérického proteinu MLL/CBP a vývoj akutní myeloidní nebo lymfoidní leukémie nebo myelodysplazie.
Gene CBP codes for a transcriptional coactivator, which can interact with many transcriptional factors. It modifies the process of transcription stimulated by these factors by specific binding to RNA polymerase II holoenzyme or by histone acetylation. CBP gene mutation is the molecular cause of autosomal dominant genetic disease called Rubinstein-Taybi syndrome that is manifested by mental and growth retardations, by typical face malformations and broad thumbs and broad big toes. The CBP gene can be affected by the t(8;16)(p11;p13.3) translocation resulting in production of the MOZ/CBP chimeric protein and in induction of acute myeloblastic leukaemia. Therapy using topoisomerase II inhibitors can induce the t(11;16)(q23;13.3) translocation causing acute myeloid or lymphoid leukaemia or myelodysplasia through production of the MLL/CBP protein chimera.
Somatic JAK2 mutations are the main molecular cause of the vast majority of polycythemia vera (PV) cases. According to a recent structural model, the prevalent acquired V617F mutation improves the stability of the JAK2 dimer, thereby enhancing the constitutive JAK2 kinase activity. Germline JAK2 mutations usually do not largely alter JAK2 signaling, although they may modulate the impact of V617F. We found an unusual germline JAK2 mutation L604F in homozygous form in a young PV patient, along with a low allele burden JAK2 V617F mutation, and in her apparently healthy sister. Their father with a PV-like disease had L604F in a heterozygous state, without V617F. The functional consequences of JAK2 L604Fmutation were compared with those induced by V617F in two different in vitro model systems: (i) HEK293T cells were transfected with plasmids for exogenous JAK2-GFP expression, and (ii) endogenous JAK2 modifications were introduced into HeLa cells using CRISPR/Cas9. Both mutations significantly increased JAK2 constitutive activity in transfected HEK293T cells. In the second model, JAK2 modification resulted in reduced total JAK2 protein levels. An important difference was also detected: as described previously, the effect of V617F on JAK2 kinase activity was abrogated in the absence of the aromatic residue F595. In contrast, JAK2 hyperactivation by L604F was only partially inhibited by the F595 change to alanine. We propose that the L604F mutation increases the probability of spontaneous JAK2 dimer formation, which is physiologically mediated by F595. In addition, L604F may contribute to dimer stabilization similarly to V617F.
- MeSH
- HEK293 Cells MeSH
- HeLa Cells MeSH
- Janus Kinase 2 genetics MeSH
- Humans MeSH
- Mutation MeSH
- Germ Cells * MeSH
- Germ-Line Mutation * MeSH
- Check Tag
- Humans MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
Východisko. Tuberózní skleróza je autozomálně dominantní onemocnění charakterizované tvorbou novotvarů – hamartomů v různých orgánových systémech. Příčinou je mutace jednoho ze dvou tumor supresorových genů TSC1 nebo TSC2. Odhalování kauzálních mutací je vzhledem k jejich náhodné distribuci velmi náročné. Metody a výsledky. Práce referuje o provedení první prenatální diagnostiky tuberózní sklerózy v České republice založené na znalosti příčinné mutace. U těhotné ženy z rodiny s mutací Q435X byla provedena ve 13. týdnu gravidity denaturační gradientová gelová elektroforéza (DGGE) vzorku fetální DNA. Závěry. Vyšetření vyloučilo přítomnost sledované poruchy TSC1 genu u potomka.
Background. Tuberous sclerosis is an autosomal-dominant disease characterised by development of benign growth - hamartomas in different organs. Disorder is caused by mutations affecting either of the tumor-suppressor genes, TSC1 or TSC2. Quest for causing mutations is very difficult due to their random distribution over the genes. Methods and Results. Article refers on accomplishment of the first tuberous sclerosis prenatal diagnostics in Czech Republic based on knowledge of causing mutation. Foetal DNA sample, obtained in 13th week from Q435X family pregnant woman, was analyzed by DGGE method. Conclusions. Examination excluded presence of tested TSC1 gene defect in an offspring.
Some of the APC negative FAP and AFAP cases have recently been found to be attributable to MYH associated polyposis (MAP). MAP is an autosomal recessive syndrome associated with 5-100 colorectal adenomas and caused by mutation in the MYH gene. Here, we screened for germline MYH mutations in 82 APC-mutation-negative probands with classical and attenuated familial adenomatous polyposis using the denaturing high performance liquid chromatography (DHPLC) method in combination with sequencing. Altogether 12 previously reported changes and four novel genetic alterations, mostly in intronic sequences, were identified. The results revealed the presence of biallelic germline MYH mutations in two patients. These patients were compound heterozygotes for two of the most common germline mutations c.494 A>G (p.Y165C); c.1,145 G>A (p.G382D). These variants are established to be associated with adenomatous polyposis and colorectal cancer. No novel pathogenic mutation has been identified in our study.
- MeSH
- DNA, Neoplasm genetics MeSH
- Exons genetics MeSH
- Adenomatous Polyposis Coli genetics MeSH
- Financing, Organized MeSH
- Genes, APC MeSH
- Humans MeSH
- DNA Mutational Analysis MeSH
- Myosin Heavy Chains genetics MeSH
- Germ-Line Mutation genetics MeSH
- Check Tag
- Humans MeSH
- Publication type
- Multicenter Study MeSH
- Geographicals
- Czech Republic MeSH
Polycythemia vera (PV) is a clonal disorder arising from the acquired somatic mutations of the JAK2 gene, including JAK2V617F or several others in exon 12. A 38-year-old female had a stroke at age 32 and found to have elevated hemoglobin, normal leukocytes, normal platelets, and tested negative for JAK2V617F and exon 12 mutations. Next generation sequencing revealed a novel mutation: JAK2R715T in the pseudokinase domain (JH2) at 47.5%. Its presence in her nail DNA confirmed a germline origin. Her mother and her son similarly had erythrocytosis and a JAK2R715T mutation. Computer modeling indicated gain-of-function JAK2 activity. The propositus and her mother had polyclonal myelopoiesis, ruling out another somatic mutation-derived clonal hematopoiesis. Some erythroid progenitors of all three generations grew without erythropoietin, a hallmark of PV. The in vitro reporter assay confirmed increased activity of the JAK2R715T kinase. Similar to PV, the JAK2R715T native cells have increased STAT5 phosphorylation, augmented transcripts of prothrombotic and inflammatory genes, and decreased KLF2 transcripts. The propositus was not controlled by hydroxyurea, and JAK2 inhibitors were not tolerated; however, Ropeginterferon-alfa-2b (Ropeg-IFN-α) induced a remission. Ropeg-IFN-α treatment also reduced JAK2 activity in the propositus, her mother and JAK2V617F PV subjects. We report dominantly inherited erythrocytosis secondary to a novel germline JAK2R715T gain-of-function mutation with many but not all comparable molecular features to JAK2V617F PV. We also document a previously unreported inhibitory mechanism of JAK2 signaling by Ropeg-IFN-α.
- MeSH
- Gain of Function Mutation MeSH
- Adult MeSH
- Interferon-alpha therapeutic use MeSH
- Janus Kinase 2 * genetics MeSH
- Humans MeSH
- Polycythemia * genetics drug therapy MeSH
- Polycythemia Vera genetics drug therapy MeSH
- Pedigree MeSH
- Germ-Line Mutation * MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Case Reports MeSH
Objective: To report a case of mitochondrial retinopathy, highlighting its clinical and imaging findings, the importance of genetic confirmation, and the possible implications of heteroplasmy in this disease. Material and Methods: Case report of a mitochondrial retinopathy secondary to m.3243A>G mutation in the MT-TL1 gene. Results: A 32-year-old woman presented with bilateral vision loss, photophobia, and sensorineural hearing loss for more than 3 years. Best corrected visual acuity (BCVA) was 20/60 in the right eye (OD) and 20/25 in the left eye (OS). Fundus examination revealed multiple macular subretinal yellow-white deposits and central chorioretinal atrophy, without edema, hemorrhage, or subretinal fluid in the RE, and juxtafoveal atrophy with retinal pigment epithelium (RPE) metaplasia in the OS. Multimodal imaging raised suspicion of retinal dystrophy, and genetic testing confirmed a mitochondrial retinopathy secondary to the m.3243A>G mutation in the MT-TL1 gene. Conclusions: Bilateral and symmetric RPE atrophic changes in young individuals, especially when associated with systemic symptoms, should prompt a comprehensive evaluation, including multimodal imaging and genetic testing. Identifying causative mutations and understanding the dynamics of mitochondrial DNA in the pathogenesis of these diseases is crucial for improving diagnosis and suggesting potential therapeutic strategies, including gene therapy.
- MeSH
- Adult MeSH
- Heteroplasmy MeSH
- Humans MeSH
- DNA, Mitochondrial genetics MeSH
- Mitochondrial Diseases * diagnosis genetics MeSH
- Mutation MeSH
- Retinal Diseases * diagnosis genetics MeSH
- RNA, Transfer, Leu genetics MeSH
- Check Tag
- Adult MeSH
- Humans MeSH
- Female MeSH
- Publication type
- Case Reports MeSH
