MEDNIK syndrome is a rare autosomal recessive disease characterized by mental retardation, enteropathy, deafness, peripheral neuropathy, ichthyosis, and keratoderma, and caused by variants in the adaptor-related protein complex 1 subunit sigma 1 (AP1S1) gene. This gene encodes the σ1A protein, which is a subunit of the adaptor protein complex 1 (AP-1), a key component of the intracellular protein trafficking machinery. Previous work identified three AP1S1 nonsense, frameshift and splice-site variants in MEDNIK patients predicted to encode truncated σ1A proteins, with consequent AP-1 dysfunction. However, two AP1S1 missense variants (c.269 T > C and c.346G > A) were recently reported in patients who presented with severe enteropathy but no additional symptoms of MEDNIK. This condition was described as a novel non-syndromic form of congenital diarrhea caused specifically by the AP1S1 missense variants. In this study, we report two patients with the same c.269 T > C variant, who, contrary to the previous cases, presented as complete MEDNIK syndrome. These data substantially revise the presentation of disorders associated with AP1S1 gene variants and indicate that all the identified pathogenic AP1S1 variants result in MEDNIK syndrome. We also provide a series of functional analyses that elucidate the impact of the c.269 T > C variant on σ1A function, contributing to a better understanding of the molecular pathogenesis of MEDNIK syndrome. KEY MESSAGES: A missense AP1S1 c.269 T > C (σ1A L90P) variant causes full MEDNIK syndrome. The σ1A L90P variant is largely unable to assemble into the AP-1 complex. The σ1A L90P variant fails to bind [DE]XXXL[LI] sorting motifs. The σ1A L90P variant results in loss-of-function of the protein.

• MeSH
• adaptorový proteinový komplex - sigma-podjednotky * genetika   MeSH
• adaptorový proteinový komplex 1 * genetika   MeSH
• genetická predispozice k nemoci MeSH
• lidé MeSH
• mentální retardace genetika   MeSH
• missense mutace * MeSH
• průjem genetika   MeSH
• syndrom MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Intramural MeSH

Our study presents a novel germline c.1715G>T (p.G572V) mutation in the gene encoding Toll-like receptor 8 (TLR8) causing an autoimmune and autoinflammatory disorder in a family with monozygotic male twins, who suffer from severe autoimmune hemolytic anemia worsening with infections, and autoinflammation presenting as fevers, enteritis, arthritis, and CNS vasculitis. The pathogenicity of the mutation was confirmed by in vitro assays on transfected cell lines and primary cells. The p.G572V mutation causes impaired stability of the TLR8 protein, cross-reactivity to TLR7 ligands and reduced ability of TLR8 to attenuate TLR7 signaling. This imbalance toward TLR7-dependent signaling leads to increased pro-inflammatory responses, such as nuclear factor-κB (NF-κB) activation and production of pro-inflammatory cytokines IL-1β, IL-6, and TNFα. This unique TLR8 mutation with partial TLR8 protein loss and hyperinflammatory phenotype mediated by TLR7 ligands represents a novel inborn error of immunity with childhood-onset and a good response to TLR7 inhibition.

• MeSH
• autoimunitní hemolytická anemie genetika   imunologie   MeSH
• cytokiny genetika   imunologie   MeSH
• dvojčata monozygotní MeSH
• HEK293 buňky MeSH
• lidé MeSH
• mutace * MeSH
• posouzení stavu pacienta MeSH
• toll-like receptor 7 genetika   imunologie   MeSH
• toll-like receptor 8 genetika   imunologie   MeSH
• zánět genetika   imunologie   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• studie na dvojčatech MeSH

• MeSH
• buněčné klony MeSH
• buňky K562 MeSH
• CRISPR-Cas systémy MeSH
• genový knockout MeSH
• homozygot MeSH
• hyperhomocysteinemie farmakoterapie   genetika   MeSH
• kultivované buňky MeSH
• kyselina listová terapeutické užití   MeSH
• lidé MeSH
• megaloblastová anemie farmakoterapie   genetika   MeSH
• mladiství MeSH
• posunová mutace MeSH
• recidiva MeSH
• sekvenční delece MeSH
• sekvenování exomu MeSH
• sodíko-vodíkový výměnný transportér 1 nedostatek   genetika   MeSH
• vitamin B 12 terapeutické užití   MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• Publikační typ
• dopisy MeSH
• kazuistiky MeSH
• práce podpořená grantem MeSH

• Publikační typ
• abstrakt z konference MeSH

Mutations in the Sterile alpha motif domain containing 9 (SAMD9) gene have been described in patients with severe multisystem disorder, MIRAGE syndrome, but also in patients with bone marrow (BM) failure in the absence of other systemic symptoms. The role of hematopoietic stem cell transplantation (HSCT) in the management of the disease is still unclear. Here, we present a patient with a novel mutation in SAMD9 (c.2471 G>A, p.R824Q), manifesting with prominent gastrointestinal tract involvement and immunodeficiency, but without any sign of adrenal insufficiency typical for MIRAGE syndrome. He suffered from severe CMV (cytomegalovirus) infection at 3 months of age, with a delayed development of T lymphocyte functional response against CMV, profound T cell activation, significantly reduced B lymphocyte counts and impaired lymphocyte proliferative response. Cultured T cells displayed slightly lower calcium flux and decreased survival. At the age of 6 months, he developed severe neutropenia requiring G-CSF administration, and despite only mild morphological and immunophenotypical disturbances in the BM, 78% of the BM cells showed monosomy 7 at the age of 18 months. Surprisingly, T cell proliferation after CD3 stimulation and apoptosis of the cells normalized during the follow-up, possibly reflecting the gradual development of monosomy 7. Among other prominent symptoms, he had difficulty swallowing, requiring percutaneous endoscopic gastrostomy (PEG), frequent gastrointestinal infections, and perianal erosions. He suffered from repeated infections and periodic recurring fevers with the elevation of inflammatory markers. At 26 months of age, he underwent HSCT that significantly improved hematological and immunological laboratory parameters. Nevertheless, he continued to suffer from other conditions, and subsequently, he died at day 440 post-transplant due to sepsis. Pathogenicity of this novel SAMD9 mutation was confirmed experimentally. Expression of mutant SAMD9 caused a significant decrease in proliferation and increase in cell death of the transfected cells. Conclusion: We describe a novel SAMD9 mutation in a patient with prominent gastrointestinal and immunological symptoms but without adrenal hypoplasia. Thus, SAMD9 mutations should be considered as cause of enteropathy in pediatric patients. The insufficient therapeutic outcome of transplantation further questions the role of HSCT in the management of patients with SAMD9 mutations and multisystem involvement.

• MeSH
• cytomegalovirové infekce genetika   imunologie   MeSH
• kojenec MeSH
• lidé MeSH
• mutace MeSH
• neutropenie genetika   MeSH
• předškolní dítě MeSH
• protein Smad8 genetika   MeSH
• syndromy imunologické nedostatečnosti genetika   MeSH
• Check Tag
• kojenec MeSH
• lidé MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• Publikační typ
• kazuistiky MeSH
• práce podpořená grantem MeSH

• Publikační typ
• abstrakt z konference MeSH

Genová editace je považována za největší pokrok v molekulárně genetických metodách od objevu polymerázové řetězové reakce. Díky této technologii dnes můžeme provádět cílené změny v nukleotidové sekvenci DNA s mnohem větší přesností a účinností, než bylo doposud možné. Využití nachází genová editace téměř ve všech biotechnologických oborech, neboť výrazně zjednodušuje studium funkce genů a biologických procesů. Nejpopulárnějším nástrojem genové editace je tzv. systém CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR Associated Protein 9), který si díky své relativně snadné konstrukci a vysoké účinnosti vydobyl výsadní postavení v molekulární biologii a jeho ohromný potenciál se již začíná uplatňovat i v translační medicíně. Cílem tohoto souhrnného článku je představení genové editace a shrnutí nejvýznamnějších aplikací této unikátní technologie ve výzkumu, diagnostice a léčbě hematologických onemocnění.

Genome editing is considered to be the biggest advance in molecular genetics since the discovery of the polymerase chain reaction. This method enables the introduction of changes in a target DNA sequence with unprecedented accuracy and efficiency. Since it greatly facilitates the study of genes and biological processes, it has been employed in basic research across all biotechnology fields. The CRISPR/Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR Associated Protein 9) system is the most widely used genome-editing platform. Due to its relatively easy construction and high efficiency, this system has revolutionized the field of molecular biology and also holds enormous potential in translational medicine. The aim of this review is to introduce genome-editing technique and summarize the most important applications of this unique technology in research, diagnostics and treatment of haematologic diseases.

• MeSH
• CRISPR-Cas systémy * MeSH
• editace genu metody   MeSH
• genetické nemoci vrozené genetika   terapie   MeSH
• krevní nemoci * diagnóza   genetika   terapie   MeSH
• lidé MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH