Bernard-Soulier syndrome (BSS) is a rare inherited disorder characterized by unusually large platelets, low platelet count, and prolonged bleeding time. BSS is usually inherited in an autosomal recessive (AR) mode of inheritance due to a deficiency of the GPIb-IX-V complex also known as the von Willebrand factor (VWF) receptor. We investigated a family with macrothrombocytopenia, a mild bleeding tendency, slightly lowered platelet aggregation tests, and suspected autosomal dominant (AD) inheritance. We have detected a heterozygous GP1BA likely pathogenic variant, causing monoallelic BSS. A germline GP1BA gene variant (NM_000173:c.98G > A:p.C33Y), segregating with the macrothrombocytopenia, was detected by whole-exome sequencing. In silico analysis of the protein structure of the novel GPIbα variant revealed a potential structural defect, which could impact proper protein folding and subsequent binding to VWF. Flow cytometry, immunoblot, and electron microscopy demonstrated further differences between p.C33Y GP1BA carriers and healthy controls. Here, we provide a detailed insight into its clinical presentation and phenotype. Moreover, the here described case first presents an mBSS patient with two previous ischemic strokes.

• MeSH
• alely * MeSH
• Bernardův-Soulierův syndrom krev   diagnóza   genetika   MeSH
• fenotyp * MeSH
• genetická predispozice k nemoci * MeSH
• genetická variace * MeSH
• genetické asociační studie MeSH
• imunofenotypizace MeSH
• lidé MeSH
• mutační analýza DNA MeSH
• počet trombocytů MeSH
• rodokmen MeSH
• trombocytopenie krev   diagnóza   MeSH
• trombocytový glykoproteinový komplex Ib-IX genetika   metabolismus   MeSH
• trombocyty metabolismus   ultrastruktura   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Geografické názvy
• Česká republika MeSH

Mutations in the GP1BA gene have been associated with platelet-type von Willebrand disease and Bernard-Soulier syndrome. Here, we report a novel GP1BA mutation in a family with autosomal dominant macrothrombocytopenia and mild bleeding. We performed analyses of seven family members. Using whole-exome sequencing of germline DNA samples, we identified a heterozygous single-nucleotide change in GP1BA (exone2:c.176T>G), encoding a p.Leu59Arg substitution in the N-terminal domain, segregating with macrothrombocytopenia. This variant has not been previously reported. We also analysed the structure of the detected sequence variant in silico. In particular, we used the crystal structure of the human platelet receptor GP Ibα N-terminal domain. Replacement of aliphatic amino-acid Leu 59 with charged, polar and larger arginine probably disrupts the protein structure. An autosomal dominant mode of inheritance, a family history of mild bleeding episodes, aggregation pattern in affected individuals together with evidence of mutation occurring in part of the GP1BA gene encoding the leucine-rich repeat region suggest a novel variant causing monoallelic Bernard-Soulier syndrome.

• MeSH
• Bernardův-Soulierův syndrom genetika   metabolismus   MeSH
• bodová mutace * MeSH
• krystalografie rentgenová MeSH
• lidé MeSH
• proteinové domény MeSH
• trombocytový glykoproteinový komplex Ib-IX chemie   genetika   metabolismus   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH

Východiska: Familiární onemocnění krvetvorby (familial hematopoietic disorders – FHD) jsou vzácnou a heterogenní skupinou onemocnění, do které se řadí dědičné anemie, dědičné trombocytopenie, vrozené neutropenie a vrozené syndromy selhání kostní dřeně. Pro FHD je charakteristická variabilní klinická expresivita a neúplná penetrance fenotypu i v rámci jedné rodiny, což znesnadňuje určení správné anamnézy. Molekulární genetické defekty FHD se nachází ve > 300 genech zodpovědných zejména za buněčné procesy, jejichž funkční poruchy vedou k symptomatické cytopenii, dysfunkci orgánů, poškození tkání a k rozvoji syndromů. Některé varianty genů predisponují ke vzniku závažných hematologických malignit či vzácněji solidních nádorů. Na našem pracovišti jsme zavedli genetickou analýzu u rodin s podezřením na dědičné hematologické onemocnění. Naše zaměření je v rámci ČR unikátní. Soubor pacientů a metody: Od roku 2017 se věnujeme výzkumu a diagnostice vzácných nemocí FHD. Celkem jsme zanalyzovali 92 rodin s podezřením na FHD pomocí moderních genomických přístupů jako je celoexomové sekvenování, predikční analýza in silico, metoda MLPA a Sangerovo sekvenování. Výsledky: U 70 rodin jsme detekovali již známou patogenní / pravděpodobně patogenní variantu nebo novou variantu nejasného klinického významu (variant of unclear clinical significance – VUS), jejichž záchyt vedl k potvrzení nebo upřesnění diagnózy. Pozitivní nálezy poukázaly na výskyt dědičných trombocytopenií (geny TUBB1, ETV6 a ANKRD26 – riziko rozvoje hematologických malignit), Glanzmannových trombastenií (ITGA2B), anemií, talasemií, ale také na výskyt vzácných syndromových onemocnění, v ČR např. Bernard-Soulier (GP1BA); Heřmanský-Pudlák (HPS1); Wiskott-Aldrich (WAS – zvýšené riziko výskytu malignit); Shwachman-Diamondův syndrom (SBDS – 30% riziko myeloidních malignit) a Sebastianův syndrom (MYH9) apod. Závěr: Genetická diagnostika se stala součástí standardního vyšetření pacientů s dědičným hematologickým onemocněním. Zároveň pomohla objasnit mnohé nevyřešené případy a poukázala na výskyt vzácných variant klasifikovaných jako VUS, u nichž je nutné prokázat jejich funkční dopad pomocí proteomických technologií. Potvrzení diagnózy pacienta má také kladný dopad na jeho individualizovanou péči a ke stanovení rizika vzniku malignit či jiných přídavných onemocnění.

Background: Familial hematopoietic disorders (FHD) are a rare and heterogeneous group of disorders that include hereditary anemias, hereditary thrombocytopenias (inherited thrombocytopenias – IT), congenital neutropenias and congenital bone marrow failure syndromes. FHD is characterized by variable clinical expressivity and incomplete penetrance of the phenotype even within a single family, making it difficult to determine a correct history. The molecular genetic defects of FHD are found in > 300 genes mainly responsible for cellular processes whose functional disorders lead to symptomatic cytopenia, organ dysfunction, tissue damage and syndromes. Some gene variants predispose to the development of severe hematological malignancies or, more rarely, solid tumours. At our institution, we have introduced genetic analysis in families with suspected hereditary hematological diseases. Our focus is unique in the Czech Republic. Patients and methods: In total, we analyzed 92 families with suspected FHD using modern genomic approaches such as whole-exome sequencing (WES), in silico predictive analysis, multiplex ligation-dependent probe amplification (MLPA) and Sanger sequencing. Results: In 70 families, we detected an already known pathogenic/probably pathogenic variant or a novel variant of unclear clinical significance (VUS), the detection of which led to confirmation or refinement of the diagnosis. Positive findings indicated the occurrence of hereditary thrombocytopenias (TUBB1, ETV6 and ANKRD26 genes – risk of the development of hematological malignancies), Glanzmann thrombasthenia (ITGA2B), anemias, thalassemias, but also the occurrence of rare syndromic diseases in the Czech Republic, e. g. Bernard-Soulier (GP1BA); Heřmanský-Pudlák (HPS1); Wiskott-Aldrich (WAS – increased risk of malignancies); Shwachman-Diamond syndrome (SBDS – a 30% risk of myeloid malignancies) and Sebastian syndrome (MYH9), etc. Conclusion: Genetic diagnosis has become part of the standard examination of patients with hereditary hematological diseases. It has also helped to clarify many unsolved cases and highlighted the occurrence of rare variants classified as VUS, for which it is necessary to determine their functional impact. Confirming a patient’s diagnosis also has a positive impact on their individualized care and on determining their risk of malignancies or other additional diseases.

• MeSH
• genetické nemoci vrozené diagnóza   genetika   MeSH
• genetické testování metody   MeSH
• krevní nemoci * diagnóza   genetika   MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• práce podpořená grantem MeSH

METHODS: The studied group comprises 124 patients with acute myocardial infarction on dual antiplatelet therapy with acetylsalicylic acid (ASA) and thienopyridines. Antiplatelet therapy was monitored by platelet-rich plasma light transmittance aggregometry (LTA) using the APACT 4004 analyzer (Helena Laboratories) and by whole blood impedance aggregometry (multiple electrode aggregometry [MEA]) using the Multiplate analyzer (Dynabyte). Platelet aggregation was detected after stimulation with arachidonic acid for detection of aspirin resistance and with adenosine diphosphate (ADP) and prostaglandin E1 for detection of thienopyridine resistance. To determine the frequencies of P2Y12 (i-744T>C; rs2046934), P2Y12 (34C>T; rs6785930), COX-1 (-842A>G; rs10306114), GPVI (13254T>C; rs1613662), and GPIbA (5T>C; rs2243093) polymorphisms, DNA of patients with AIM was tested by real-time-polymerase chain reaction and melting curve analysis using the LightCycler 480 analyzer (Roche Diagnostics). RESULTS: The cut-off points used for patients with effective ASA therapy are 25% of aggregated platelets and 220 area under the curve (AUC)/min if LTA or MEA, respectively. The cut-off points used for effective thienopyridine therapy are 45% of aggregated platelets or 298 AUC/min, respectively. Both LTA and MEA found that aspirin and thienopyridine therapies failed in 14.51% and 25.8%, respectively. The data were statistically processed using the SPSS version 15 software (SPSS, Inc.). Associations between receptor mutation status and response to therapy were assessed with Fisher's exact test. The significance level was set at 0.05. CONCLUSION: The aim of our work was to use the two functional laboratory methods described earlier to assess both aspirin and thienopyridine resistance and to determine the contribution of genetic polymorphisms of platelet receptors to resistance to antiplatelet therapy in AIM. Fisher's exact test showed a significant statistical correlation between platelet function tests suitable for monitoring ASA resistance, that is, LTA and MEA, and mutation status of COX1_A1 (-A842G). Fisher's exact test showed no statistically significant correlations between platelet function tests suitable for monitoring ASA resistance, that is, LTA and MEA, and mutation status of GP1bA (-5T>C) and GP6 (T13254C). Fisher's exact test showed no statistically significant correlation between mutational statuses of the receptors P2RY12 (i-T744C), P2RY12 (C34T), GP1bA (-5T>C), or GP6 (T13254C) and response to antiplatelet therapy with 75 mg of clopidogrel.

• MeSH
• antigeny trombocytů genetika   MeSH
• bodová mutace * MeSH
• dospělí MeSH
• infarkt myokardu * farmakoterapie   genetika   MeSH
• inhibitory agregace trombocytů aplikace a dávkování   MeSH
• léková rezistence * MeSH
• lidé středního věku MeSH
• lidé MeSH
• pilotní projekty MeSH
• polymorfismus genetický * MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

A single-center study was conducted on 120 patients with inherited disorders of primary hemostasis followed at our hematological center. These patients presented a variety of bleeding symptoms; however, they had no definitive diagnosis. Establishing a diagnosis has consequences for the investigation of probands in families and for treatment management; therefore, we aimed to improve the diagnosis rate in these patients by implementing advanced diagnostic methods. According to the accepted international guidelines at the time of study, we investigated platelet morphology, platelet function assay, light-transmission aggregometry, and flow cytometry. Using only these methods, we were unable to make a definitive diagnosis for most of our patients. However, next-generation sequencing (NGS), which was applied in 31 patients, allowed us to establish definitive diagnoses in six cases (variants in ANKRD26, ITGA2B, and F8) and helped us to identify suspected variants (NBEAL2, F2, BLOC1S6, AP3D1, GP1BB, ANO6, CD36, and ITGB3) and new suspected variants (GFI1B, FGA, GP1BA, and ITGA2B) in 11 patients. The role of NGS in patients with suspicious bleeding symptoms is growing and it changes the diagnostic algorithm. The greatest disadvantage of NGS, aside from the cost, is the occurrence of gene variants of uncertain significance.

• MeSH
• krevní proteiny genetika   MeSH
• krvácení MeSH
• lidé MeSH
• trombocytopatie * diagnóza   genetika   MeSH
• vyšetření funkce trombocytů MeSH
• vysoce účinné nukleotidové sekvenování MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Česká republika MeSH