Adenosine Deaminase Deficiency Research Articles

Urticarial vasculitis

Purpose of review Urticarial vasculitis is a rare condition manifesting with a variety of clinical presentations ranging from skin limited lesions to life-threatening systemic illnesses. This review aims to highlight the recent findings on the etiology, diagnostic modalities, and therapeutic strategies and course of urticarial vasculitis. Recent findings In addition to well established triggers, urticarial vasculitis (UV) cases associated with severe acute respiratory syndrome coronavirus 2 (SARS-Cov2) disease and COVID-19 vaccines, vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic (VEXAS) syndrome, and adenosine deaminase (ADA) deficiency have been reported. A clinical-dermoscopic model for differentiating urticarial vasculitis has been developed with purpuric patches and globules favoring UV diagnosis and thus diminishing the need for histopathology. The efficacy of treatment modalities has been reviewed, and antihistamines, systemic corticosteroids, omalizumab, cyclophosphamide, tocilizumab, anti-interleukin (IL)-1 agents, and rituximab were shown to have the highest success rates. Regarding the durability of remission, rituximab, dapsone, and MMF were related to long-lasting treatment free responses. The course of hypocomplementemic urticarial vasculitis was investigated in an epidemiological study, revealing 5- and 10-year survival rates of 92% and 83%, respectively. Chronic obstructive pulmonary disease, septicemia, and end-stage renal disease were identified as causes of mortality. Summary With the aid of dermoscopy, a noninvasive tool, differentiation from chronic spontaneous urticaria can be made, and the need for histopathological examination can be diminished. Although clear definitions and consensus criteria for performing disease severity are lacking, careful screening is needed to tailor the treatment on an individual basis. Emerging infections like SARS-CoV 2, vaccines, and autoinflammatory disorders like VEXAS syndrome and ADA deficiency are new associations. The optimal use of well established agents like systemic corticosteroids and immunomodulators are mainstay treatment modalities, whereas IL-1 inhibitors, omalizumab, rituximab and Janus Kinase inhibitors may represent viable alternatives in selected cases.

Clinical spectrum and outcome of children with deficiency of adenosine deaminase 2 (DADA2): multicentric experience from India.

Deficiency of adenosine deaminase-2 (DADA2) is a monogenic disorder closely resembling polyarteritis nodosa (PAN) and can present to physicians across various specialties. Through this case series, we aim to describe the clinical spectrum and outcome of Indian children with DADA2. We aimed to study the clinical spectrum and outcome of Indian children with DADA-2. The deidentified data from all participating centres were entered in an excel sheet, and the coordinating centre (All India Institute of Medical Sciences, New Delhi) screened the data for accuracy and completeness. We enrolled 16 children (11 females) in the study; the mean (SD) age at the time of onset of symptoms for males and females was 46.2 (47) and 73.6 (50.4) months, respectively. The most common clinical feature in this cohort was fever and rash in 80% of patients. More than half of children n, (%) [8, (53%)] had a CNS stroke. The other clinical features were hypertension [5(33%)], anaemia [3 (20%)] and arthralgia/arthritis in 4 (26%). These children were managed with various immunomodulators: steroids [13, (86%)], anti-TNF agents [(12, (80%)], cyclophosphamide [2 (13%)] and mycophenolate mofetil [3 (20%)]. The median (IQR) duration of follow-up for this cohort was 17 (10, 29) months. Fourteen children achieved remission and none had recurrent strokes after the initiation of anti-TNF drugs. DADA-2 closely resembles PAN; early age of onset and CNS stroke are striking differentiating features from classic PAN. Most children respond well to anti-TNF agents without serious adverse events during short-term follow-up.

Early bone marrow alterations in patients with adenosine deaminase 2 deficiency across disease phenotypes and severities

Deficiency of adenosine deaminase 2 (DADA2) is a complex monogenic disease caused by recessive mutations in the ADA2 gene. DADA2 exhibits a broad clinical spectrum encompassing vasculitis, immunodeficiency, and hematological abnormalities. Yet, the impact of DADA2 on the bone marrow (BM) microenvironment is largely unexplored. This study comprehensively examined the BM and peripheral blood of pediatric and adult patients with DADA2 presenting rheumatologic/immunologic symptoms or severe hematological manifestations. Immunophenotyping of hematopoietic stem cells (HSCs), progenitor cells, and mature cell populations was performed for 18 patients with DADA2. We also conducted a characterization of the mesenchymal stromal cells (MSCs). Our study revealed a significant decrease in primitive HSCs and progenitor cells, alongside their reduced clonogenic capacity and multilineage differentiation potential. These BM defects were evident in patients with both severe and non-severe hematological manifestations, including pediatric patients, demonstrating that BM disruption can emerge silently and early on, even in patients who do not show obvious hematological symptoms. Beyond stem cells, there was a reduction in mature cell populations in the BM and peripheral blood, affecting myeloid, erythroid, and lymphoid populations. Furthermore, BM MSCs in DADA2 patients exhibited reduced clonogenic and proliferation capabilities and were more prone to undergo cellular senescence marked by elevated DNA damage. Our exploration into the BM landscape of DADA2 patients sheds light on the critical hematological dimension of the disease and emphasizes the importance of vigilant monitoring, even in the case of subclinical presentation.

Deficiency of adenosine deaminase 2 (DADA2) presented with bilateral renal subcapsular hematoma: a case report and literature review

Deficiency of adenosine deaminase 2 (DADA2) presented with bilateral renal subcapsular hematoma: a case report and literature review

Deficiency of Adenosine Deaminase 2

Adenosine deaminase 2 (ADA2) deficiency is an autosomal recessively inherited autoinflammatory disorder caused by loss-of-function mutations in the ADA2 gene. Although the pathogenesis involves the triggering of a proinflammatory cascade due to increased production of inflammatory cytokines such as tumor necrosis factor (TNF)-α and dysregulation of neutrophil extracellular trap formation resulting from an excess accumulation of extracellular adenosine, the pathogenetic mechanism still needs further clarification due to the broad clinical spectrum. In addition to the initially described vasculitis-related symptoms, hematological, immunological, and autoinflammatory symptoms are now well recognized. The diagnosis is made by demonstration of pathogenic variants of ADA2 with biallelic loss of function and identification of low plasma ADA2 catalytic activity. Currently, TNF-α inhibitors are the treatment of choice for controlling vasculitis manifestations and preventing strokes. However, in patients presenting with severe hematologic findings, TNF-α inhibitors are not the treatment of choice and hematopoietic stem cell transplantation has been shown to be successful in selected cases. Recombinant ADA2 protein and gene therapy are promising treatment modalities for the future. In conclusion, ADA2 deficiency has a broad phenotype and should be considered in the differential diagnosis of different clinical situations. In this review, we summarize the disease manifestations of ADA2 deficiency and available treatment options.

Evolving spectrum of adenosine deaminase (ADA) deficiency: Assessing genotype pathogenicity according to expressed ADA activity of 46 variants

Deficiency of adenosine deaminase (ADA or ADA1) has broad clinical and genetic heterogeneity. Screening techniques can identify asymptomatic infants whose phenotype and prognosis are indeterminate, and who may carry ADA variants of unknown significance. We systematically assessed the pathogenic potential of rare ADA missense variants to better define the relationship of genotype to red blood cell (RBC) total deoxyadenosine nucleotide (dAXP) content and to phenotype. We expressed 46 ADA missense variants in the ADA-deficient SØ3834 strain of Escherichia coli and defined genotype categories (GCs) ranked I to IV by increasing expressed ADA activity. We assessed relationships among GC rank, RBC dAXP, and phenotype in 58 reference patients with 50 different genotypes. We used our GC ranking system to benchmark AlphaMissense for predicting variant pathogenicity, and we used a minigene assay to identify exonic splicing variants in ADA exon 9. The 46 missense variants expressed ∼0.001% to ∼70% of wild-type ADA activity (40% had <0.05% of wild-type ADA activity and 50% expressed >1%). RBC dAXP ranged from undetectable to >75% of total adenine nucleotides and correlated well with phenotype. Both RBC dAXP and clinical severity were inversely related to total ADA activity expressed by both inherited variants. Our GC scoring system performed better than AlphaMissense in assessing variant pathogenicity, particularly for less deleterious variants. For ADA deficiency, pathogenicity is a continuum and conditional, depending on the total ADA activity contributed by both inherited variants as indicated by GC rank. However, in patients with indeterminate phenotype identified by screening, RBC dAXP measured at diagnosis may have greater prognostic value than GC rank.

ADA2 regulates inflammation and hematopoietic stem cell emergence via the A2bR pathway in zebrafish

Deficiency of adenosine deaminase 2 (DADA2) is an inborn error of immunity caused by loss-of-function mutations in the adenosine deaminase 2 (ADA2) gene. Clinical manifestations of DADA2 include vasculopathy and immuno-hematological abnormalities, culminating in bone marrow failure. A major gap exists in our knowledge of the regulatory functions of ADA2 during inflammation and hematopoiesis, mainly due to the absence of an ADA2 orthologue in rodents. Exploring these mechanisms is essential for understanding disease pathology and developing new treatments. Zebrafish possess two ADA2 orthologues, cecr1a and cecr1b, with the latter showing functional conservation with human ADA2. We establish a cecr1b-loss-of-function zebrafish model that recapitulates the immuno-hematological and vascular manifestations observed in humans. Loss of Cecr1b disrupts hematopoietic stem cell specification, resulting in defective hematopoiesis. This defect is caused by induced inflammation in the vascular endothelium. Blocking inflammation, pharmacological modulation of the A2r pathway, or the administration of the recombinant human ADA2 corrects these defects, providing insights into the mechanistic link between ADA2 deficiency, inflammation and immuno-hematological abnormalities. Our findings open up potential therapeutic avenues for DADA2 patients.

Development of EBV Related Diffuse Large B-cell Lymphoma in Deficiency of Adenosine Deaminase 2 with Uncontrolled EBV Infection

Deficiency of Adenosine Deaminase 2 (DADA2) patients presenting with primary immunodeficiency are at risk of uncontrolled EBV infection and secondary malignancies including EBV-related lymphoproliferative disorders (LPD). This paper describes the first case of EBV related diffuse large B-cell lymphoma in a patient with DADA2 and uncontrolled EBV infection. Consideration should be given to monitoring for EBV viraemia and to preventative EBV specific therapy in DADA2 and patients with at risk primary immunodeficiencies. A type I interferon (IFN) gene signature is associated with DADA2 though its association with immune dysregulation is unclear.

A case of T-cell acute lymphoblastic leukemia in retroviral gene therapy for ADA-SCID.

Hematopoietic stem cell gene therapy (GT) using a γ-retroviral vector (γ-RV) is an effective treatment for Severe Combined Immunodeficiency due to Adenosine Deaminase deficiency. Here, we describe a case of GT-related T-cell acute lymphoblastic leukemia (T-ALL) that developed 4.7 years after treatment. The patient underwent chemotherapy and haploidentical transplantation and is currently in remission. Blast cells contain a single vector insertion activating the LIM-only protein 2 (LMO2) proto-oncogene, confirmed by physical interaction, and low Adenosine Deaminase (ADA) activity resulting from methylation of viral promoter. The insertion is detected years before T-ALL in multiple lineages, suggesting that further hits occurred in a thymic progenitor. Blast cells contain known and novel somatic mutations as well as germline mutations which may have contributed to transformation. Before T-ALL onset, the insertion profile is similar to those of other ADA-deficient patients. The limited incidence of vector-related adverse events in ADA-deficiency compared to other γ-RV GT trials could be explained by differences in transgenes, background disease and patient's specific factors.

128 Increased dosage of elapegademase-lvlr improved metabolic and immunologic function in a patient with late-onset adenosine deaminase deficiency and neutralizing anti-drug antibodies

128 Increased dosage of elapegademase-lvlr improved metabolic and immunologic function in a patient with late-onset adenosine deaminase deficiency and neutralizing anti-drug antibodies

Expanded Newborn Screening for Inborn Errors of Immunity: The Experience of Tuscany

Inborn errors of immunity (IEIs) include 485 inherited disorders characterized by an increased susceptibility to life threatening infectious diseases, autoimmunity and malignant diseases with a high mortality rate in the first years of life. Severe Combined Immunodeficiency is the most severe of the IEIs and its detection should be a primary goal in a newborn screening (NBS) program. The term "actionable" has recently been used for all IEIs with outcomes that can be demonstrably improved through early specialized intervention. to evaluate the results of the expanded NBS strategy for IEIs in Tuscany Region (Italy), based on TREC (T-cell Receptor Excision Circles), KREC (Kappa Recombining Excision Circles) and Tandem Mass-based assays. This is a retrospective study collecting data from all infants born in Tuscany from October 10, 2018, to October 10, 2022. Tandem mass assay to identify Adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) deficiency, together with TREC and KREC molecular analysis were conducted on dried blood spot (DBS) from the newborns' Guthrie Cards. A new DBS and evaluation by an immunologist were carried out when the results of the first test were outside the diagnostic cut-offs. 94,319 newborns were evaluated. Referral rates for TREC (0.031%) and KREC (0.074%) in this study are in line with the data available in literature. The results from the expanded NBS strategy revealed an incidence rate of 1/9,431 affected newborns. This work represents the first description of a sustainable and real-life based expanded NBS program for IEIs with a high diagnostic incidence facilitating prompt management of identified patients.

Lung Gene Expression Suggests Roles for Interferon-Stimulated Genes and Adenosine Deaminase Acting against RNA-1 in Pathologic Responses to Diisocyanate.

Mechanisms underlying methylene diphenyl diisocyanate (MDI) and other low molecular weight chemical-induced asthma are unclear and appear distinct from those of high molecular weight (HMW) allergen-induced asthma. We sought to elucidate molecular pathways that differentiate asthma-like pathogenic vs nonpathogenic responses to respiratory tract MDI exposure in a murine model. Lung gene expression differences in MDI exposed immune-sensitized and nonsensitized mice vs unexposed controls were measured by microarrays, and associated molecular pathways were identified through bioinformatic analyses and further compared with published studies of a prototypic HMW asthmagen (ovalbumin). Respiratory tract MDI exposure significantly altered lung gene expression in both nonsensitized and immune-sensitized mice, vs controls. Fifty-three gene transcripts were altered in all MDI exposed lung tissue vs controls, with levels up to 10-fold higher in immune-sensitized vs nonsensitized mice. Gene transcripts selectively increased in MDI exposed immune-sensitized animals were dominated by chitinases and chemokines and showed substantial overlap with those increased in ovalbumin-induced asthma. In contrast, MDI exposure of nonsensitized mice increased type I interferon stimulated genes (ISGs) in a pattern reflecting deficiency in adenosine deaminase acting against RNA (ADAR-1), an important regulator of innate, as well as "sterile" or autoimmunity triggered by tissue damage. Thus, MDI-induced changes in lung gene expression were identified that differentiate nonpathogenic innate responses in nonsensitized hosts from pathologic adaptive responses in immune-sensitized hosts. The data suggest that MDI alters unique biological pathways involving ISGs and ADAR-1, potentially explaining its unique immunogenicity/allergenicity.

Update on ocular manifestations of the main monogenic and polygenic autoinflammatory diseases.

Autoinflammatory diseases include disorders with a genetic cause and also complex syndromes associated to polygenic or multifactorial factors. Eye involvement is present in many of them, with different extent and severity. The present review covers ophthalmological lesions in the most prevalent monogenic autoinflammatory diseases, including FMF (familial Mediterranean fever), TRAPS (TNF receptor-associated periodic syndrome), CAPS (cryopyrin-associated periodic syndromes), Blau syndrome, DADA2 (deficiency of adenosine deaminase 2), DITRA (deficiency of the interleukin-36 receptor antagonist), other monogenic disorders, including several ubiquitinopathies, interferonopathies, and the recently described ROSAH (retinal dystrophy, optic nerve edema, splenomegaly, anhidrosis, and headache) syndrome, and VEXAS (vacuoles, E1 enzyme, X-linked, autoinflammatory, somatic) syndrome. Among polygenic autoinflammatory diseases, ocular manifestations have been reviewed in Behçet's disease, PFAPA (periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis) syndrome, Still's disease and autoinflammatory bone diseases, which encompass CRMO (chronic recurrent multifocal osteomyelitis) and SAPHO (synovitis, acne, pustulosis, hyperostosis and osteitis) syndrome.

Clinical Characteristics and Outcomes of Polyarteritis Nodosa: An International Study.

We describe the demographics, clinical features, disease course, and survival of polyarteritis nodosa (PAN) through an international collaboration (GLOBAL-PAN). Patients with PAN were recruited between 1990 and 2020 from observational cohorts of nine countries across Europe, Japan, and North America. Eligibility was retrospectively defined using the European Medicines Agency classification algorithm. Patients with PAN related to hepatitis B virus (n=12) and two monogenic diseases mimicking PAN, deficiency of adenosine deaminase 2 enzyme (n=16) or familial Mediterranean fever (n=11), were excluded. Data regarding organ involvement, relapse, disease-related damage, and survival were analyzed. Three hundred fifty-eight patients (female:male ratio 174:184), including those with systemic PAN (sPAN, n=282) and cutaneous PAN (n=76), were included. Twenty-five were pediatric onset. Mean ± SD age at diagnosis was 44.3 ± 18.1 years. Constitutional symptoms (71.5%), cutaneous involvement (70.5%), musculoskeletal findings (69.1%), and neurologic features (48.0%) were common manifestations. Among patients with sPAN, gastrointestinal involvement and proteinuria over 400 mg/day were reported in 52.2% and 11.2%, respectively. During a median (interquartile range) 59.6 (99.5) months of follow-up, relapse occurred in 48.5% of patients. One, 5- and 10-year survival rates for sPAN were 97.1%, 94.0%, and 89.0%, respectively. Predictors of death for sPAN included age ≥65 years at diagnosis, serum creatinine at diagnosis >140 μmol/L, gastrointestinal manifestations, and central nervous system (CNS) involvement. The spectrum of PAN remains a complex, multifaceted disease. Relapse is common. Age ≥65 years and serum creatinine >140 μmol/L at diagnosis, as well as gastrointestinal and CNS involvement, are independent predictors of death in sPAN.

Long-term and real-world safety and efficacy of retroviral gene therapy for adenosine deaminase deficiency.

Adenosine deaminase (ADA) deficiency leads to severe combined immunodeficiency (SCID). Previous clinical trials showed that autologous CD34+ cell gene therapy (GT) following busulfan reduced-intensity conditioning is a promising therapeutic approach for ADA-SCID, but long-term data are warranted. Here we report an analysis on long-term safety and efficacy data of 43 patients with ADA-SCID who received retroviral ex vivo bone marrow-derived hematopoietic stem cell GT. Twenty-two individuals (median follow-up 15.4 years) were treated in the context of clinical development or named patient program. Nineteen patients were treated post-marketing authorization (median follow-up 3.2 years), and two additional patients received mobilized peripheral blood CD34+ cell GT. At data cutoff, all 43 patients were alive, with a median follow-up of 5.0 years (interquartile range 2.4-15.4) and 2 years intervention-free survival (no need for long-term enzyme replacement therapy or allogeneic hematopoietic stem cell transplantation) of 88% (95% confidence interval 78.7-98.4%). Most adverse events/reactions were related to disease background, busulfan conditioning or immune reconstitution; the safety profile of the real world experience was in line with premarketing cohort. One patient from the named patient program developed a T cell leukemia related to treatment 4.7 years after GT and is currently in remission. Long-term persistence of multilineage gene-corrected cells, metabolic detoxification, immune reconstitution and decreased infection rates were observed. Estimated mixed-effects models showed that higher dose of CD34+ cells infused and younger age at GT affected positively the plateau of CD3+ transduced cells, lymphocytes and CD4+ CD45RA+ naive T cells, whereas the cell dose positively influenced the final plateau of CD15+ transduced cells. These long-term data suggest that the risk-benefit of GT in ADA remains favorable and warrant for continuing long-term safety monitoring. Clinical trial registration: NCT00598481 , NCT03478670 .

Gene therapy for adenosine deaminase severe combined immune deficiency-An unexpected journey of four decades.

Severe combined immune deficiency due to adenosine deaminase deficiency (ADA SCID) is an inborn error of immunity with pan-lymphopenia, due to accumulated cytotoxic adenine metabolites. ADA SCID has been treated using gene therapy with a normal human ADA gene added to autologous hematopoietic stem cells (HSC) for over 30 years. Iterative improvements in vector design, HSC processing methods, and clinical HSC transplant procedures have led nearly all ADA SCID gene therapy patients to achieve consistently beneficial immune restoration with stable engraftment of ADA gene-corrected HSC over the duration of observation (as long as 20 years). One gene therapy for ADA SCID is approved by the European Medicines Agency (EMA) in the European Union (EU) and another is being advanced to licensure in the U.S. and U.K. Despite the clear-cut benefits and safety of this curative gene and cell therapy, it remains challenging to achieve sustained availability and access, especially for rare disorders like ADA SCID.

Neurological phenotype of adenosine deaminase 2 deficient patients: a cohort study.

Patients with adenosine deaminase 2 (ADA2) deficiency can present with various neurological manifestations due to vasculopathies and autoinflammation. These include ischaemic and hemorrhagic stroke, but less clearly defined neurological symptoms have also been reported. In this cohort study, patients with confirmed ADA2 deficiency from seven university hospitals in the Netherlands were included. The frequency and recurrence rates of neurological manifestations before and after initiation of tumor necrosis factor α (TNF-α) inhibiting therapy were analyzed. Twenty-nine patients were included with a median age at presentation of 5 years (interquartile range 1-17). Neurological manifestations occurred in 19/29 (66%) patients and were the presenting symptom in 9/29 (31%) patients. Transient ischaemic attack (TIA)/ischaemic stroke occurred in 12/29 (41%) patients and was the presenting symptom in 8/29 (28%) patients. In total, 25 TIAs/ischaemic strokes occurred in 12 patients, one after initiation of TNF-α inhibiting therapy and one whilst switching between TNF-α inhibitors. None was large-vessel occlusion stroke. Two hemorrhagic strokes occurred: one aneurysmatic subarachnoid hemorrhage and one spontaneous intracerebral hemorrhage. Most neurological symptoms, including cranial nerve deficits, vertigo, ataxia and seizures, were caused by TIAs/ischaemic strokes and seldom recurred after initiation of TNF-α inhibiting therapy. Neurological manifestations, especially TIA/ischaemic stroke, are common in patients with ADA2 deficiency and frequently are the presenting symptom. Because it is a treatable cause of young stroke, for which antiplatelet and anticoagulant therapy are considered contraindicated, awareness amongst neurologists and pediatricians is important. Screening for ADA2 deficiency in young patients with small-vessel ischaemic stroke without an identified cause should be considered.

Cerebral Aneurysms and Recurrent TIAs in a 42-Year-Old Patient With DADA2 Mutation: A Case Report.

Deficiency of adenosine deaminase 2 (DADA2) is a rare, recessively inherited autoinflammatory disease with a wide clinical spectrum of manifestations, including strokes and vasculitis. We report a case of a patient with DADA2 who presented with neurologic manifestations. A 42-year-old woman with a known diagnosis of polyarteritis nodosa experienced several episodes of TIAs. Neuroimaging revealed 2 aneurysms in unusual locations. Her young age, ethnic origin, absent of cardiovascular risk factors, and skin involvement raised the suspicion of DADA2. Genetic testing confirmed the diagnosis, and a directed treatment with anti-TNF was initiated. DADA2, although thought to be rare, needs to be borne in mind when evaluating patients with a combination of neurologic and systemic symptoms, as early diagnosis and treatment are imperative in preventing permanent disability.

Whole exome sequencing reveals a missense mutation in the ADA gene causing severe combined immune deficiency in a Pakistani family ADA gene mutation causing SCID

BACKGROUND &amp; OBJECTIVE: Human adenosine deaminase deficiency, OMIM 102700 (ADA deficiency) is a genetic disorder which causes severe combined immunodeficiency (SCID). The enzyme adenosine deaminase is a housekeeping in nature and is involved in purine catabolism by catalyzing irreversible deamination of adenosine and deoxyadenosine. The SCID patients’ immune system is unable to fight off most of the bacterial and fungal infections due to profound lymphopenia (T-B-NK+). About 20% of the SCID patients are genetically homozygous for defective ADA gene. In our study we aimed to find out genetic variant in ADA gene in a family carrying severe combined immune deficiency. Objective in the current study is to unravel and characterize the molecular cause of the patient suffering from by birth SCID.&#x0D; METHODOLOGY: In the present study we enrolled a 6-month-old female SCID patient belonging to highly consanguineous Pakistani family. Patient clinical features included repeated chest infection with failure to thrive, fever and chronic diarrhea. Whole blood samples from patient, parents and healthy siblings were acquired in EDTA tubes. DNA was extracted from all the blood samples.&#x0D; RESULTS: Flowcytometry revealed lymphopenia (T-B-NK+) type of SCID. Whole Exome Sequencing (WES) identified a one nucleotide change (c.716G&gt;A) in ADA gene exon 8. The segregation of the identified variant in the family was confirmed through Sanger Sequencing.&#x0D; CONCLUSION: In this study, we presented detailed clinical and genetic description of patient suffering from severe combined immune deficiency. The immunological and genetic findings presented in this study will facilitate early diagnosis of the disease. Segregation of the identified variant in the family members will also aid in genetic counseling the family.

Computational 3D structure prediction followed by molecular docking to reveal the novel drug targets against ADA

Adenosine deaminase (ADA) is a functional enzyme that transforms deoxyadenosine and adenosine into deoxyinosine and inosine respectively. ADA deficiency causes toxic purine degradation byproducts to build up in the body, which has a particularly negative impact on lymphocytes and results in adenosine deaminase-deficient severe combined immunodeficiency. Different in silico techniques including threading, ab initio and homology modeling for 3D structure prediction were applied for the prediction of ADA structures. Following the three-dimensional structure prediction analyses, an extensive computational assessment of all predicted structures for reliability was performed. The overall quality factor of the predicted ADA structures was observed 62.45% in the predicted 3D models. A Ramachandran plot was created, and 94.80% of the residues were found in the allowed and favored regions of the protein structure plot. The molecular docking analyses were performed in order to identify the potential therapeutic medication targets against ADA. The virtually examined molecules through a virtually high throughput screening may have the ability the regulation the ADA activity. The least binding energy was calculated through the molecular docking analyses and the energy values were observed -8.7 Kcal/mol. The binding residues (Lys-367, Glu-424, Asp-422, Phe-381, Ile-377, Ser-430 and Glu-374) were conserved in all the interactional analyses of the docked complexes. Finding the effective binding domain in a protein three-dimensional structure is crucial for understanding of its structural makeup and determining its functions.