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At least 19 recordsLinked to original sources
PubMed2026

Genetic Heterogeneity of Inborn Errors of Immunity Revealed by Whole-Genome Sequencing: Insights from a Russian Patient Cohort.

Identifying genetic cause(s) is a key step for management and treatment of patients with inborn errors of immunity (IEI). Here, in an observational cross-sectional genomic study, we analyzed whole-genome sequencing (WGS) data of 72 IEI patients from Saint Petersburg and Northwestern Russia: 42 patients with common variable immunodeficiency (CVID)-like phenotypes, 6 patients with clinically diagnosed X-linked agammaglobulinemia (XLA or Bruton's disease), and 24 patients with other forms of IEI. Causative pathogenic and likely pathogenic variants in BTK, CYBB, CHD7, AIRE, ATM, SBDS, NFKB1, and CTLA4 genes were identified in 14 (19%) patients. Variants of uncertain significance that could be linked to observed clinical phenotypes were detected in 6 patients. These included a BTK variant in a patient with Bruton's disease, variants in SH2D1A, SOCS1, and IKBKB in patients with CVID, and variants in CARD11 and CD40LG in patients with other forms of IEI. Additional rare variants that were mostly unique to individual patients were found in multiple IEI genes from the International Union of Immunological Societies (IUIS) Expert Committee 2024 list. In the CVID-like subcohort, pathway-level analysis of these rare variants revealed patterns associated with clinical manifestations. Taken together, our results expand the genetic characterization of an understudied regional IEI cohort, particularly of patients with CVID-like phenotypes, and identify genetic factors that are implicated in or may contribute to the disease.

Humans↗
PubMed2026

Recurrent and unusual infections unmasking a rare inborn error of immunity: a case report RAS-associated Autoimmune Lymphoproliferative Disease (RALD).

BACKGROUND: RAS-associated Autoimmune Lymphoproliferative Disease (RALD) is a rare, non-malignant lymphoproliferative disorder caused by somatic mutations in RAS genes that impair lymphocyte apoptosis. Patients often present with features of lymphoproliferation, autoimmune manifestations, and an increased risk of malignant transformation. CASE PRESENTATION: We report the case of a 3-year-old boy with splenic microabscesses and Burkholderia pseudomallei IgM serology positivity, who was treated as melioidosis. He had recurrent respiratory infections and chronic rhinorrhoea since the age of one year. Clinical examination revealed persistent lymphadenopathy and hepatosplenomegaly. Laboratory investigations demonstrated persistent absolute monocytosis and thrombocytopenia, while immunological evaluation showed elevated IgM levels and B-cell lymphocytosis. Whole exome sequencing identified a heterozygous pathogenic variant in NRAS, NM_002524.5:c.35G > C, NP_002515.1:p.Gly12Ala, establishing the diagnosis of RALD. The patient was subsequently started on antibiotic prophylaxis and immunoglobulin replacement therapy, and his family was counseled regarding the potential role of immunosuppressive therapy and hematopoietic stem cell transplantation (HSCT) in future management. CONCLUSIONS: This case highlights the coexistence of an unusual infection with a rare inborn error of immunity, expanding the recognized infectious spectrum of RALD. It underscores the importance of considering RALD in patients presenting with recurrent or atypical infections and persistent lymphoproliferative features. Early recognition and molecular genetic testing are essential for confirming the diagnosis and guiding individualized management.

Humans↗
PubMed2026

Immune dysregulatory disorders: perspective from solving a diagnostic odyssey.

PURPOSE OF REVIEW: Inborn errors of immunity (IEIs), once considered rare disorders characterized primarily by recurrent infections, are now recognized as a rapidly expanding group of diseases encompassing autoimmunity, autoinflammation, allergy, malignancy, and immune dysregulation. Advances in next-generation sequencing, functional immunology, and systems biology have revealed overlap between traditionally distinct disease categories and highlighted the complexity of genotype-phenotype relationships. RECENT FINDINGS: While this evolution has led to the discovery of hundreds of previously unrecognized disorders, it has also challenged conventional diagnostic paradigms and demonstrated how patients may have care spread across multiple specialties, without a clear medical home. These discoveries have also highlighted ongoing challenges translating scientific findings to the clinic including difficulties in accessing genomic testing, interpretation of variants of uncertain significance, impacts of incomplete penetrance and somatic mosaicism, and limited availability of specialized functional assays. Emerging computational approaches, including artificial intelligence, offer opportunities to accelerate diagnosis but cannot replace comprehensive clinical evaluation or longitudinal physician-patient relationships. SUMMARY: This perspective examines how the diagnostic odyssey for immune dysregulatory disorders has evolved, side-by-side with the changing framework for diagnosing rare immune diseases. We propose an integrated approach combining clinical phenotyping, genomics, functional validation, and multidisciplinary expertise to unite ongoing discovery between clinicians and scientists, diagnostics, and patient outcomes.

diagnostic odyssey↗
PubMed2026

GATA2 deficiency: enhancer deregulation, immune surveillance failure, and clonal evolution.

Germline mutations in GATA2 cause a syndromic inborn error of immunity characterized by cytopenia, infections, immune dysregulation, and a marked predisposition to myelodysplastic syndrome and acute myeloid leukemia. Initially defined by the DCML phenotype-dendritic cell, monocyte, B- and NK-cell deficiency-GATA2 deficiency is now recognized as a disorder of global immune-hematopoietic homeostasis. Recent multi-omics and experimental models reveal enhancer-driven inflammatory rewiring, IRF8-dependent lineage imbalance, and premature hematopoietic aging. In parallel, adaptive immune defects, including impaired B- and T-cell development and function, contribute to defective immune surveillance. These alterations not only explain susceptibility to infection but also shape clonal evolution and malignant transformation. Clinically, improved risk stratification and transplant outcomes underscore the importance of early recognition and monitoring of immune dysfunction. GATA2 deficiency thus represents a paradigm linking immune dysregulation, inflammatory stress, and cancer predisposition.

Humans↗
PubMed2026

Hyper-IgE syndromes in pediatrics: clinical spectrum, differential diagnosis, and management.

Hyper-IgE syndromes (HIES) are rare inborn errors of immunity (≈1 per million) caused by pathogenic variants in STAT3, DOCK8 or IL6ST. They present with very high serum immunoglobulin E (IgE), recurrent bacterial or fungal infections, eczema and characteristic organ involvement. The autosomal dominant STAT3-deficient form features early-onset eczema, “cold” abscesses, recurrent pneumonias with pneumatoceles and skeletal or dental anomalies. Autosomal recessive forms such as DOCK8 or PGM3 deficiency show a more severe phenotype with viral skin infections, allergy, asthma and increased malignancy risk. HIES should be suspected in children with IgE >2000 IU/mL plus recurrent sinopulmonary or skin infections, severe eczema, atypical viral infections or a National Institutes of Health Hyper-IgE Syndrome (NIH HIES) score >40. Differentiation from severe atopic dermatitis, asthma, eosinophilic disorders and parasitic infections is essential. Evaluation includes eosinophils, lymphocyte subsets, T-helper 17 (Th17) cell analysis and targeted genetic testing. Management involves antimicrobial prophylaxis, treatment of complications, dermatologic care and genotype-based hematopoietic stem cell transplantation (HSCT), which is curative in DOCK8 but less effective in STAT3 deficiency. Early genomic confirmation enables timely recognition, identification of red flags, and genotype-specific therapy to improve long-term outcomes.

Humans↗
PubMed2026

Facial Dysmorphism and Severe Vascular Phenotype in TRNT1 Deficiency with Concomitant Antithrombin III Deficiency.

TRNT1 deficiency (SIFD syndrome) is a rare inborn error of immunity characterized by sideroblastic anemia, immunodeficiency, periodic fevers, and developmental delay. We report two Romanian patients with genetically confirmed TRNT1 deficiency presenting with characteristic hematologic and immunologic abnormalities and a distinctive facial dysmorphism. One patient additionally developed severe gastrointestinal ischemia and intracranial hemorrhage in the setting of concomitant hereditary antithrombin III deficiency. These observations expand the phenotypic spectrum associated with TRNT1 deficiency and highlight the marked clinical variability of this disorder. The contribution of TRNT1-associated inflammation to the vascular phenotype remains speculative and cannot be distinguished from the effects of the concomitant thrombophilic condition.

Humans↗
PubMed2026

Prediction of human missense variant effects from functional evidence.

Prediction of missense variant effects remains a critical bottleneck in both research and diagnostic genetics. Current predictors typically rely on clinical outcomes or population patterns rather than direct measures of functional impact, leading to limited generalizability and data circularity. Here we present FuncVEP, a family of variant effect predictors trained on diverse functional data to predict the functional impact of missense variants. FuncVEP generalizes across datasets and outperforms 48 existing predictors across a wide range of benchmarks, improving accuracy from 78.8% to 84.6% on functional benchmarks and from 90.1% to 92.4% on clinical benchmarks. From a discovery perspective, we identified 210 new gene-phenotype associations involving 494 genes linked to inborn errors of immunity in the UK Biobank and the Mount Sinai Million Health Discoveries Program. FuncVEP substantially improved the discovery rate relative to state-of-the-art predictors. Overall, FuncVEP provides a robust, scalable solution for variant interpretation, advancing both diagnostic precision and gene discovery.

Humans↗
PubMed2026

Structural modeling and functional characterization of a novel gain-of-function TLR8 variant causing severe inflammatory syndrome.

With the increasing use of genetic sequencing to investigate inborn errors of immunity, rare variants are frequently identified, yet their clinical relevance often remains uncertain. Establishing pathogenicity requires a multidisciplinary approach that integrates genetic, structural, functional, and clinical data. Here, we used such a strategy to investigate a previously unreported hemizygous missense variant - alanine (A) to threonine (T) at residue 518 - in Toll-like receptor 8 (TLR8), identified in 2 male siblings with recurrent infections and systemic inflammation, characterized by a proinflammatory immune signature and B cell dysregulation. Functional studies showed that the TLR8 A518T variant enhanced NF-κB activation and increased secretion of proinflammatory cytokines compared with WT TLR8 upon stimulation, consistent with a gain-of-function effect. Protein degradation and turnover assays revealed reduced abundance of the mutant TLR8 protein due to faster turnover and increased proteasomal degradation. Computational modeling predicted enhanced structural stabilization of the active TLR8 homodimer interface via additional water-mediated hydrogen bonds introduced by the A518T substitution. Together, these findings integrating structural modeling with functional assays identify a novel TLR8 ligand-specific gain-of-function mutation resulting in complex immunopathology in 2 siblings.

Humans↗
PubMed2020

Human NK cell deficiency as a result of biallelic mutations in MCM10.

Human natural killer cell deficiency (NKD) arises from inborn errors of immunity that lead to impaired NK cell development, function, or both. Through the understanding of the biological perturbations in individuals with NKD, requirements for the generation of terminally mature functional innate effector cells can be elucidated. Here, we report a cause of NKD resulting from compound heterozygous mutations in minichromosomal maintenance complex member 10 (MCM10) that impaired NK cell maturation in a child with fatal susceptibility to CMV. MCM10 has not been previously associated with monogenic disease and plays a critical role in the activation and function of the eukaryotic DNA replisome. Through evaluation of patient primary fibroblasts, modeling patient mutations in fibroblast cell lines, and MCM10 knockdown in human NK cell lines, we have shown that loss of MCM10 function leads to impaired cell cycle progression and induction of DNA damage-response pathways. By modeling MCM10 deficiency in primary NK cell precursors, including patient-derived induced pluripotent stem cells, we further demonstrated that MCM10 is required for NK cell terminal maturation and acquisition of immunological system function. Together, these data define MCM10 as an NKD gene and provide biological insight into the requirement for the DNA replisome in human NK cell maturation and function.

Alleles↗
PubMed2026

Human GPR174 deficiency drives polyclonal lymphoproliferative disease via defects in T cell function.

The X-linked G-protein coupled receptor GPR174 is highly expressed in T and B lymphocytes and has immunoregulatory roles in mice, but its function in humans is unknown. We describe a cohort of six individuals who have function-disrupting variants in GPR174 and a clinical phenotype of lymphadenopathy and autoimmunity. Histological analysis of two patient lymph nodes revealed necrotizing lymphadenitis and lymphoproliferation resembling Kikuchi-Fujimoto disease. In-depth analysis of three patients and related carriers revealed overaccumulation of CD8 terminally differentiated effector memory cells re-expressing CD45RA (TEMRA). Patient cells and GPR174-deficient CD8 T cells generated from controls showed less repression of proliferation by the GPR174 ligand lysophosphatidylserine (lysoPS) and an effector-biased gene expression program. GPR174-deficient CD4 T cells were resistant to lysoPS-mediated suppression of IL2 production. In mice, chronic viral infection led to over-accumulation of GPR174-deficient effector CD8 T cells. We describe an inborn error of immunity associated with dysregulated lymphocyte responses that we propose predisposes to exaggerated lymphoproliferation and autoimmunity following viral infection.

Journal Article↗
PubMed2026

Defective RNA Polymerase III sensing of mitochondrial DNA in pulmonary epithelial cells impairs type I IFN immunity to SARS-CoV-2.

The clinical spectrum of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection ranges from asymptomatic cases to critical COVID-19 pneumonia. To investigate the role of host genetics in susceptibility to critical COVID-19 and identify pathophysiological mechanisms and pathways, we analyzed whole-exome and whole-genome sequencing data from the COVID Human Genetic Effort. We identified 10 rare, monoallelic predicted loss-of-function variants in 18 patients in POLR3A and POLR3C encoding two subunits of RNA polymerase III (POL III), a nuclear multisubunit enzyme, which has been implicated in cytosolic DNA sensing. These variants were deleterious for expression of full-length POLR3A and POLR3C proteins. We demonstrate that human pulmonary A549-hACE2 cells with reduced POLR3A or POLR3C expression exhibit impaired type I IFN responses to transfected mitochondrial DNA (mtDNA) or SARS-CoV-2 infection, together with increased viral replication. Mechanistically, we show that SARS-CoV-2 induces cellular mtDNA release via oligomerization of the mitochondrial voltage-dependent anion channel under virus-induced oxidative stress, enabling POL III-mtDNA interaction. These findings establish POL III as a sensor of endogenous mtDNA released during viral infection and indicate that autosomal dominant POL III haploinsufficiency may predispose individuals to critical COVID-19.

Humans↗
PubMed2025

Genetic Landscape and Mitochondrial Metabolic Dysregulation in Patients Suffering From Severe Long COVID.

Long COVID represents a significant global health challenge with an unclear etiology. Alongside accumulating evidence of mitochondrial dysfunction in patients with acute SARS-CoV-2 infection, a symptomatic overlap exists between long COVID and mitochondrial disorders. However, the genetic underpinnings of mitochondrial dysfunction in long COVID have not been previously explored. We employed whole genome sequencing to analyze 13 patients with severe long COVID to identify genetic defects related to mitochondrial function. We performed extracellular bioenergetics flux analysis on peripheral blood mononuclear cells and proteomics to evaluate cellular bioenergetics and compared the results to those of healthy controls. Our investigation identified 10 variants classified as pathogenic or likely pathogenic and 83 variants of unknown significance affecting a wide range of mitochondria-associated biological functions. Bioenergetics flux analysis in peripheral blood mononuclear cells revealed an altered ATP production rate in four long COVID patients compared to healthy controls. This study presents initial evidence of a potential underlying genetic predisposition to mitochondrial dysfunction in long COVID while demonstrating altered cellular energy capacity in a subset of these patients. These findings open avenues for further research into the role of mitochondrial dysfunction and pathology in patients suffering from long COVID and may pave the way for targeted therapeutic strategies aimed at mitigating mitochondrial dysfunction.

Humans↗
PubMed2025

The potential impacts of human genetics on virus emergence.

Human monogenic traits can confer resistance to viral infection in exposed individuals or predisposition to severe disease in infected individuals. Enhanced susceptibility can be driven directly by mutations in genes essential for control of the virus or indirectly via the production of autoantibodies against components of host defense. While the impact of viruses on individuals carrying these genotypes permitted their identification and has been amply studied, little is known about the impact of these human genotypes on the natural history of viruses, including not only persisting but also emerging viruses. We envisage several scenarios, including the possibility that genetically susceptible individuals serve as patient zeros, superspreaders, or mutation incubators, or that genetically resistant individuals even permit the selection of new viral mutants. Viruses are continually shared between individuals and even host species, where they can benefit from adaption to new environments. Current human viruses, as well as novel viruses from animal reservoirs, will continue to threaten the human population. Improvements in the scale of human genomic sequencing and analysis will permit testing hypotheses about the impact of human genetics on the origin and trajectory of viral infections, including future pandemics, which may ultimately help to prevent or curtail impending outbreaks.

Humans↗
PubMed2026

An Update on Inborn Errors of V(D)J Recombination.

V(D)J recombination is the fundamental process by which developing T and B lymphocytes generate diverse antigen receptors, enabling adaptive immunity. This tightly regulated program operates exclusively in lymphoid precursors during G1 phase and depends on the lymphocyte-specific RAG1-RAG2 recombinase to introduce programmed DNA double-strand breaks at recombination signal sequences, followed by repair through the classical nonhomologous end joining (c-NHEJ) pathway. Disruption of any step in this molecular choreography compromises antigen receptor diversity and underlies a spectrum of inborn errors of immunity (IEIs), ranging from severe combined immunodeficiency (SCID) to immune dysregulation with autoimmunity and granulomatous disease. In this review, we place disorders of V(D)J recombination within the broader framework of T-cell development, detailing the temporal waves of recombinase activity, chromatin accessibility, and DNA damage responses that guide thymocyte differentiation. We discuss pathogenic variants affecting the cleavage phase [RAG1, RAG2, and the recently identified RAG cochaperone NudC domain-containing 3 (NUDCD3)], end processing (ARTEMIS), ligation and repair (LIG4, XLF, XRCC4, PRKDC), and genome surveillance pathways (ATM, MRN complex, RNF168), highlighting genotype-phenotype correlations and mechanisms driving immune deficiency and dysregulation. We briefly review recent diagnostic advances, including newborn screening using T-cell receptor excision circles, repertoire sequencing, and functional assays, alongside current therapeutic strategies. Finally, we outline key unanswered questions and argue that continued integration of clinical observation with molecular discovery is essential to improve outcomes and deepen understanding of adaptive immune development.

Humans↗