Project description:Somatic mutations in UBA1 involving hematopoietic stem and myeloid cells have been reported in patients with the newly defined VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome. Here, we report clinical hematologic manifestations and unique bone marrow (BM) features in 16 patients with VEXAS. All patients were male and had a history of severe autoinflammatory and rheumatologic manifestations and a somatic UBA1 mutation (p.Met41). Ten patients had hematologic disorders: myelodysplastic syndrome (MDS; 6 of 16), multiple myeloma (2 of 16), monoclonal gammopathy of undetermined significance (2 of 16), and monoclonal B-cell lymphocytosis (2 of 16), and a few of those patients had 2 co-existing clonal processes. Although macrocytic anemia (100%) and lymphopenia (80%) were prevalent in all patients with VEXAS, thrombocytopenia and neutropenia were more common in patients with progression to MDS. All BMs in VEXAS patients had prominent cytoplasmic vacuoles in myeloid and erythroid precursors. In addition, most BMs were hypercellular with myeloid hyperplasia, erythroid hypoplasia, and varying degrees of dysplasia. All patients diagnosed with MDS were lower risk (low blast count, very good to intermediate cytogenetics) according to standard prognostic scoring with no known progression to leukemia. In addition, 10 of 16 patients had thrombotic events, including venous thromboembolism and arterial stroke. Although VEXAS presents symptomatically as a rheumatologic disease, morbidity and mortality are associated with progression to hematologic disease. Given the increased risk of developing MDS and multiple myeloma, surveillance for disease progression is important.
Project description:BackgroundVEXAS syndrome (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic syndrome) is a recently described syndrome caused by a somatic missense variant at the methionine-41 (p.(Met41)) position in the ubiquitin-like modifier activating enzyme 1 (UBA1) in Xp11.3. Germline pathogenic variants in UBA1 are associated with a distinct phenotype: a syndrome with severe neurologic features associated with loss of anterior horn cells and infantile death denominated X-Linked Spinal Muscular Atrophy 2 (SMAX2) (OMIM 301,830).Case presentationWe report a male individual with the phenotype of VEXAS syndrome that was initially identified through exome sequencing (ES) as having a hemizygous germline variant in UBA1 due to high variant allele frequency (VAF). Research Sanger sequencing was able to confirm the absence of the p.(Met41Val) variant in a skin biopsy and in gastric mucosa tissue sample confirming the variant happened as a postzygotic event.ConclusionsThe present case exemplifies the diagnostic challenge that was imposed by the high VAF detected by ES that failed to correctly demonstrate that the variant was in a mosaic state. Sequencing of different tissues should be considered when there is conflict between the UBA1 variant status and the clinical findings.
Project description:Congenital lipomatous overgrowth with vascular, epidermal, and skeletal anomalies (CLOVES) is a sporadically occurring, nonhereditary disorder characterized by asymmetric somatic hypertrophy and anomalies in multiple organs. We hypothesized that CLOVES syndrome would be caused by a somatic mutation arising during early embryonic development. Therefore, we employed massively parallel sequencing to search for somatic mosaic mutations in fresh, frozen, or fixed archival tissue from six affected individuals. We identified mutations in PIK3CA in all six individuals, and mutant allele frequencies ranged from 3% to 30% in affected tissue from multiple embryonic lineages. Interestingly, these same mutations have been identified in cancer cells, in which they increase phosphoinositide-3-kinase activity. We conclude that CLOVES is caused by postzygotic activating mutations in PIK3CA. The application of similar sequencing strategies will probably identify additional genetic causes for sporadically occurring, nonheritable malformations.
Project description:BackgroundAdult-onset inflammatory syndromes often manifest with overlapping clinical features. Variants in ubiquitin-related genes, previously implicated in autoinflammatory disease, may define new disorders.MethodsWe analyzed peripheral-blood exome sequence data independent of clinical phenotype and inheritance pattern to identify deleterious mutations in ubiquitin-related genes. Sanger sequencing, immunoblotting, immunohistochemical testing, flow cytometry, and transcriptome and cytokine profiling were performed. CRISPR-Cas9-edited zebrafish were used as an in vivo model to assess gene function.ResultsWe identified 25 men with somatic mutations affecting methionine-41 (p.Met41) in UBA1, the major E1 enzyme that initiates ubiquitylation. (The gene UBA1 lies on the X chromosome.) In such patients, an often fatal, treatment-refractory inflammatory syndrome develops in late adulthood, with fevers, cytopenias, characteristic vacuoles in myeloid and erythroid precursor cells, dysplastic bone marrow, neutrophilic cutaneous and pulmonary inflammation, chondritis, and vasculitis. Most of these 25 patients met clinical criteria for an inflammatory syndrome (relapsing polychondritis, Sweet's syndrome, polyarteritis nodosa, or giant-cell arteritis) or a hematologic condition (myelodysplastic syndrome or multiple myeloma) or both. Mutations were found in more than half the hematopoietic stem cells, including peripheral-blood myeloid cells but not lymphocytes or fibroblasts. Mutations affecting p.Met41 resulted in loss of the canonical cytoplasmic isoform of UBA1 and in expression of a novel, catalytically impaired isoform initiated at p.Met67. Mutant peripheral-blood cells showed decreased ubiquitylation and activated innate immune pathways. Knockout of the cytoplasmic UBA1 isoform homologue in zebrafish caused systemic inflammation.ConclusionsUsing a genotype-driven approach, we identified a disorder that connects seemingly unrelated adult-onset inflammatory syndromes. We named this disorder the VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome. (Funded by the NIH Intramural Research Programs and the EU Horizon 2020 Research and Innovation Program.).
Project description:UBA1 is an X-linked gene and encodes an ubiquitin-activating enzyme. Three somatic mutations altering the alternative start codon (M41) in UBA1 in hematopoietic precursor cells have recently been described, resulting in a syndrome of severe inflammation, cytopenias, and the presence of intracellular vacuoles in hematopoietic precursors - termed VEXAS syndrome, a predominantly male disease. Here we present a patient with clinical features of VEXAS who harbored two novel somatic variants in UBA1 (I894S and N606I). To better understand the clinical relevance and biological consequences of non-M41 (UBA1non-M41) variants, we analyzed the whole genome and transcriptome data of 4168 patients with hematological malignancies and detected an additional 16 UBA1non-M41 putative somatic variants with a clear sex-bias in patients with myeloid malignancies. Patients diagnosed with myeloid malignancies carrying UBA1non-M41 putative somatic variants either had vacuoles or immunodysregulatory symptoms. Analysis of the transcriptome confirmed neutrophil activation in VEXAS patients compared to healthy controls but did not result in a specific transcriptomic signature of UBA1M41 patients in comparison with MDS patients. In summary, we have described multiple putative novel UBA1non-M41 variants in patients with various hematological malignancies expanding the genomic spectrum of VEXAS syndrome.
Project description:Oculodentodigital syndrome (ODD) is a rare, usually autosomal-dominant disorder that is characterized by developmental abnormalities of the face, eyes, teeth, and limbs. The most common clinical findings include a long, narrow nose, short palpebral fissures, type III syndactyly, and dental abnormalities including generalized microdontia and enamel hypoplasia. Recently, it has been shown that mutations in the gene GJA1, which encodes the gap junction protein connexin 43, underlie oculodentodigital syndrome. Gap junction communication between adjacent cells is known to be vital during embryogenesis and subsequently for normal tissue homeostasis. Here, we report 8 missense mutations in the coding region of GJA1, 6 of which have not been described previously, in ten unrelated families diagnosed with ODD. In addition, immunofluorescence analyses of a developmental series of mouse embryos and adult tissue demonstrates a strong correlation between the sites of connexin 43 expression and the clinical phenotype displayed by individuals affected by ODD.
Project description:VEXAS syndrome, an autoinflammatory syndrome due to a Ubiquitin Like Modifier Activating Enzyme 1 (UBA1) somatic mutation, has a high thrombotic burden. We report a case of a 69-year-old male that was diagnosed with VEXAS syndrome who developed venous thromboembolism (VTE). Review of literature of existing VEXAS syndrome cases showed a high thrombotic burden, with the reported incidence of VTE (36.4%) being markedly higher than arterial thrombosis (1.6%), with deep vein thrombosis being more common than pulmonary embolism. Somatic mutation in the UBA1 gene results in decreased ubiquitylation which is a key driver in the development of thrombosis in VEXAS syndrome, due to chronic inflammation and cytokine release from abnormal crosstalk between the intrinsic effector mechanism of innate immune cells, platelets and endothelium resulting in dysregulated haemostasis and endothelial dysfunction. Targeting endothelial dysfunction and reducing inflammatory milieu causing hypercoagulability with immunosuppressants and immunomodulatory agents, together with anticoagulation may be the strategy to prevent recurrent thrombotic events. Supplementary Information The online version contains supplementary material available at 10.1007/s11239-021-02608-y.
Project description:Integrator (INT) is an RNA polymerase II (RNAPII)-associated complex that was recently identified to have a broad role in both RNA processing and transcription regulation. INT has at least 14 subunits, but INT germline mutations causing human disease have not been reported. We identified mutations in the Integrator Complex Subunit 8 gene (INTS8) causing a rare neurodevelopmental syndrome. In patient cells we identified significant disturbance of gene expression and RNA processing. Also, we show that injection of ints8 oligonucleotide morpholinos into zebrafish embryos leads to prominent underdevelopment of the head demonstrating the evolutionary conserved requirement of INTS8 in brain development. RNA sequencing was carried out using RNA samples from fibroblasts from two individuals with germline bi-allelic INTS8 mutations and from two healthy individuals
Project description:Meckel-Gruber syndrome (MKS) is a clinically and genetically heterogeneous ciliopathy characterized by a triad of occipital encephalocele, polycystic kidneys, and postaxial polydactyly. Pathogenesis of MKS is related to dysfunction of primary cilia. However, reports on MKS caused by Tectonic2 (TCTN2) mutations are scanty whilst. There is no direct evidence of ciliogenesis in such MKS patients. Here, we identified two novel nonsense variants of TCTN2 (c.343G?>?T, p.E115*; c.1540C?>?T, p.Q514*) in a Chinese MKS fetus. Compared to reported TCTN2-causing MKS patients, our case represented an endocardial pad defect, which was not reported previously. We also found primary cilia protruded normally from the surface of epithelial cells in the affected fetal kidney tubules compared to controls, indicating TCTN2 is not necessary for ciliogenesis in the kidney. To our knowledge, this is the first case of MKS fetus caused by TCTN2 mutations from China.