APECED in Turkey: A case report and insights on genetic and phenotypic variability

Primary immune regulatory disorders (PIRD): expanding the mutation spectrum in Turkey and identification of sixteen novel variants

Human Inborn Errors of Immunity (IEIs) encompass a clinically and genetically heterogeneous group of disorders, ranging from mild cases to severe, life-threatening types. Among these, Primary Immune Regulatory Disorders (PIRDs) constitute a subset of IEIs characterized by diverse clinical phenotypes, prominently featuring severe atopy, autoimmunity, lymphoproliferation, hyperinflammation, autoinflammation, and susceptibility to malignancies. According to the latest report from the International Union of Immunological Societies (IUIS), PIRDs arise from mutations in various genes including LYST, RAB27A, AP3B1, AP3D1, PRF1, UNC13D, STX11, STXBP2, FAAP24, SLC7A7, RASGRP1, CD70, CTPS1, RLTPR, ITK, MAGT1, PRKCD, TNFRSF9, SH2DIA, XIAP, CD27 (TNFRSF7), FAS (TNFRSF6), FASLG (TNFSF6), CASP10, CASP8, FADD, LRBA, STAT3, AIRE, ITCH, ZAP70, TPP2, JAK1, PEPD, FOXP3, IL2RA, CTLA4, BACH2, IL2RB, DEF6, FERMT1, IL10, IL10RA, IL10RB, NFAT5, TGFB1, and RIPK1 genes. We designed a targeted next-generation sequencing (TNGS) workflow using the Ion AmpliSeq™ Primary Immune Deficiency Research Panel to sequence 264 genes associated with IEIs on the Ion S5™ Sequencer. In this study, we report the identification of 38 disease-causing variants, including 16 novel ones, detected in 40 patients across 15 distinct PIRD genes. The application of next-generation sequencing enabled rapid and precise diagnosis of patients with PIRDs.

Early recognition of the APECED rash can accelerate the diagnosis of APECED

Autoimmune-Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy (APECED) is a monogenic autoimmune disease most often resulting from biallelic loss-of-function variants in the autoimmune regulator (AIRE) gene. Although typically characterized by the classic triad of chronic mucocutaneous candidiasis, hypoparathyroidism, and adrenal insufficiency, we have recently reported that the clinical spectrum of the syndrome is far broader that previously described and that incorporation of an adjunct triad of APECED rash, autoimmune enteritis-associated intestinal dysfunction, and enamel hypoplasia in the classic triad manifestations could lead to earlier diagnosis. Among the adjunct triad manifestations, APECED rash occurs in 66% of American APECED patients by age 3, most often developing in the first year of life. Here, we describe the clinical and histological features of protracted APECED rash manifesting together with recurrent mucocutaneous candidiasis as the first two disease components of APECED in a 10-month-old girl.

APECED and the place of AIRE in the puzzle of the immune network associated with autoimmunity

In the last 20 years, discoveries about the autoimmune regulator (AIRE) protein and its critical role in immune tolerance have provided fundamental insights into understanding the molecular basis of autoimmunity. This review provides a comprehensive overview of the effect of AIRE on immunological tolerance and the characteristics of autoimmune diseases in Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy (APECED), which is caused by biallelic AIRE mutations. A better understanding of the immunological mechanisms of AIRE deficiency may enlighten immune tolerance mechanisms and new diagnostic and treatment strategies for autoimmune diseases. Considering that not all clinical features of APECED are present in a given follow-up period, the diagnosis is not easy in a patient at the first visit. Longer follow-up and a multidisciplinary approach are essential for diagnosis. It is challenging to prevent endocrine and other organ damage compared with other diseases associated with multiple autoimmunities, such as FOXP3, LRBA, and CTLA4 deficiencies. Unfortunately, no curative therapy like haematopoietic stem cell transplantation or specific immunomodulation is present that is successful in the treatment.

In Search for the Missing Link in APECED-like Conditions: Analysis of the AIRE Gene in a Series of 48 Patients

Autoimmune diseases are a heterogeneous group of disorders of the immune system. They can cluster in the same individual, revealing various preferential associations for polyendocrine autoimmune syndromes. Clinical observation, together with advances in genetics and the understanding of pathophysiological processes, has further highlighted that autoimmunity can be associated with immunodeficiency; autoimmunity may even be the first primary immunodeficiency manifestation. Analysis of susceptibility genes for the development of these complex phenotypes is a fundamental issue. In this manuscript, we revised the clinical and immunologic features and the presence of AIRE gene variations in a cohort of 48 patients affected by high polyautoimmunity complexity, i.e., APECED-like conditions, also including patients affected by primary immunodeficiency. Our results evidenced a significant association of the S278R polymorphism of the AIRE gene with APECED-like conditions, including both patients affected by autoimmunity and immunodeficiency and patients with polyautoimmunity compared to healthy controls. A trend of association was also observed with the IVS9+6 G>A polymorphism. The results of this genetic analysis emphasize the need to look for additional genetic determinants playing in concert with AIRE polymorphisms. This will help to improve the diagnostic workup and ensure a precision medicine approach to targeted therapies in APECED-like patients.

Autoimmune Cytopenias and Dysregulated Immunophenotype Act as Warning Signs of Inborn Errors of Immunity: Results From a Prospective Study

Inborn errors of immunity (IEI) are genetic disorders characterized by a wide spectrum of clinical manifestations, ranging from increased susceptibility to infections to significant immune dysregulation. Among these, primary immune regulatory disorders (PIRDs) are mainly presenting with autoimmune manifestations, and autoimmune cytopenias (AICs) can be the first clinical sign. Significantly, AICs in patients with IEI often fail to respond to first-line therapy. In pediatric patients, autoimmune cytopenias can be red flags for IEI. However, for these cases precise indicators or parameters useful to suspect and screen for a hidden congenital immune defect are lacking. Therefore, we focused on chronic/refractory AIC patients to perform an extensive clinical evaluation and multiparametric flow cytometry analysis to select patients in whom PIRD was strongly suspected as candidates for genetic analysis. Key IEI-associated alterations causative of STAT3 GOF disease, IKAROS haploinsufficiency, activated PI3Kδ syndrome (APDS), Kabuki syndrome and autoimmune lymphoproliferative syndrome (ALPS) were identified. In this scenario, a dysregulated immunophenotype acted as a potential screening tool for an early IEI diagnosis, pivotal for appropriate clinical management and for the identification of new therapeutic targets.

Autoimmune Polyendocrinopathy-Candidiasis-Ectodermal Dystrophy

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), also known as autoimmune polyglandular syndrome type-1 (APS-1), is a rare monogenic autoimmune disease caused by loss-of-function mutations in the autoimmune regulator (AIRE) gene. AIRE deficiency impairs immune tolerance in the thymus and results in the peripheral escape of self-reactive T lymphocytes and the generation of several cytokine- and tissue antigen-targeted autoantibodies. APECED features a classic triad of characteristic clinical manifestations consisting of chronic mucocutaneous candidiasis (CMC), hypoparathyroidism, and primary adrenal insufficiency (Addison's disease). In addition, APECED patients develop several non-endocrine autoimmune manifestations with variable frequencies, whose recognition by pediatricians should facilitate an earlier diagnosis and allow for the prompt implementation of targeted screening, preventive, and therapeutic strategies. This review summarizes our current understanding of the genetic, immunological, clinical, diagnostic, and treatment features of APECED.

Report of two siblings with APECED in Serbia: is there a founder effect of c.769C>T AIRE genotype?

BACKGROUND

Autoimmune polyendocrinopathy-candidiasis-ectodermal-dystrophy (APECED) or autoimmune polyglandular syndrome Type 1 is a rare autosomal recessive syndrome. The disorder is caused by mutations in the AIRE (AutoImmune Regulator) gene. According to the classic criteria, clinical diagnosis requires the presence of at least two of three main components: chronic mucocutaneous candidiasis, hypoparathyroidism and primary adrenal insufficiency. Furthermore, patients are often affected by other endocrine or non-endocrine associated autoimmune conditions. The enrichment of the non-classical triad seems to occur differently in different cohorts. Screenings of the population revealed that homozygous AIRE mutations c.769C > T, c.415C > T and c.254A > G have a founder effect in Finnish, Sardinian and Iranian Jew populations respectively.

CASE PRESENTATION

We report here the clinical and genetic characteristics of two new Serbian APECED siblings, one male and one female, actual age of 27 and 24 respectively, born from non-consanguineous parents. Addison's disease was diagnosed in the male at the age of 3.5 and hypoparathyroidism at the age of 4. The female developed hypoparathyroidism at 4 years of age. She presented diffuse alopecia, madarosis, onychomycosis, teeth enamel dysplasia. She further developed Addison's disease at the age of 11 and Hashimoto's thyroiditis at the age of 13.5. She had menarche at the age of 14 but developed autoimmune oophoritis and premature ovarian failure at the age of 16. A treatment with hydrocortisone, fludrocortisone and alfacalcidiol was established for both siblings; L-T4 (levo-thyroxine) for thyroid dysfunction and levonorgestrel and etinilestradiol for POF were also administered to the female. Genetic screening revealed a homozygous c.769C > T (R257X (p.Arg257X)) AIRE mutation. We additionally reviewed the literature on 11 previously published Serbian patients and evaluated the frequency of their main diseases in comparison to Finnish, Sardinian, Turkish, Indian and North/South American cohorts.

CONCLUSION

A founder effect was discovered for the R257X genotype detected in the DNA of 10 homozygous and 2 heterozygous patients. Of note, all Serbian APECED patients were affected by adrenal insufficiency and 10 out of 13 patients presented CMC.

Late-onset autoimmune polyendocrine syndrome type 1: a case report and literature review

Autoimmune polyendocrine syndrome type 1 (APS-1), also referred to as autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), a rare monogenic disorder, is classically characterized by a triad of chronic mucocutaneous candidiasis, hypoparathyroidism, and primary adrenal insufficiency. The identified causative gene is autoimmune regulator (AIRE), which encodes a critical transcription factor and is essential for self-tolerance. Here, we describe a late-onset Chinese case who presented with symptoms of persistent tetany due to hypocalcemia. Extensive clinical evaluations revealed that the patient manifested beyond the classic triad of the disease, and next-generation sequencing identified a known homozygous AIRE mutation (p.R139X). APS-1 is a rare inherited immunodeficiency disease with high clinical and genetic heterogeneity. By retrospectively analyzing the disease, we comprehensively reviewed the phenotypic features, summarized the genotype spectrum, and discussed the possible immunological mechanisms of the disease to enhance earlier recognition and implement targeted preventive and therapeutic strategies.

Autoimmune polyendocrine syndrome type 1 (APECED) in the Indian population: case report and review of a series of 45 patients

BACKGROUND

Autoimmune polyendocrinopathy-candidiasis-ectodermal-dystrophy (APECED) or autoimmune polyglandular syndrome type 1 (APS-1) is a rare autosomal recessive genetic disease due to mutations in the AIRE (AutoImmune REgulator) gene. The clinical diagnosis is classically based on the presence of at least two of the three main components: chronic mucocutaneous candidiasis, hypoparathyroidism and primary adrenal insufficiency. Patients often suffer from other endocrine or non-endocrine autoimmune conditions throughout life. APECED etiopathogenesis is mediated by T lymphocytes. Autoantibodies against proteins of the affected organs are found in the serum of APECED patients as well as neutralizing antibodies against cytokines. We report here the clinical and genetic characteristics of 45 Indian APECED patients in comparison to Finnish, Sardinian, Turkish and North/South American cohorts from their published results. We also report a new case of APECED of Indian origin, a 2-year old child suffering from chronic mucocutaneous candidiasis since the age of 8 months, with confirmatory AIRE homozygous mutation c.274C > T (p.R92W).

CONCLUSION

With the inherent limitations of a retrospective study, analysis of Indian APECED patients suggested that compared to classic criteria, application of Ferre/Lionakis criteria validated in North/South American patients could help in earlier diagnosis in 3 of 8 (37.5%) patients for whom adequate information for evaluation was available.

Autoimmune Addison's Disease as Part of the Autoimmune Polyglandular Syndrome Type 1: Historical Overview and Current Evidence

The autoimmune polyglandular syndrome type 1 (APS1) is caused by pathogenic variants of the autoimmune regulator (AIRE) gene, located in the chromosomal region 21q22.3. The related protein, AIRE, enhances thymic self-representation and immune self-tolerance by localization to chromatin and anchorage to multimolecular complexes involved in the initiation and post-initiation events of tissue-specific antigen-encoding gene transcription. Once synthesized, the self-antigens are presented to, and cause deletion of, the self-reactive thymocyte clones. The clinical diagnosis of APS1 is based on the classic triad idiopathic hypoparathyroidism (HPT)—chronic mucocutaneous candidiasis—autoimmune Addison's disease (AAD), though new criteria based on early non-endocrine manifestations have been proposed. HPT is in most cases the first endocrine component of the syndrome; however, APS1-associated AAD has received the most accurate biochemical, clinical, and immunological characterization. Here is a comprehensive review of the studies on APS1-associated AAD from initial case reports to the most recent scientific findings.

A Patient With AIRE Mutation Who Presented With Severe Diarrhea and Lung Abscess

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) (polyglandular endocrinopathy type 1) is a rare autosomal recessive disorder caused by mutations in the autoimmune regulator gene (AIRE). The major clinical features of APECED are hypoparathyroidism, adrenal insufficiency (Addison disease), and chronic mucocutaneous candidiasis. This disease is also associated with multiple other and uncommon autoimmune (autoimmune hepatitis, autoimmune enteropathy, atrophic gastritis with or without pernicious anemia, gonadal failure, diabetes mellitus, hypothyroidism, functional hyposplenism), ectodermal (alopecia and vitiligo), and inflammatory (intestinal lung disease, nephritis) features. Here, we report a case of a 13-year-old Turkish boy who presented wih enteropathy and lung abscess. Molecular genetic analysis demonstrated a homozygous frameshift mutation (p.Asp70fs, c.208_209insCAGG) in exon 2, in AIRE gene. APECED may present with severe, life-threatening infections due to functional hyposplenism. Multidisciplinary approach, careful follow-up, and molecular genetic studies are needed.

Primary Immunodeficiencies in Russia: Data From the National Registry

Introduction: Primary immunodeficiencies (PID) are a group of rare genetic disorders with a multitude of clinical symptoms. Characterization of epidemiological and clinical data via national registries has proven to be a valuable tool of studying these diseases. Materials and Methods: The Russian PID registry was set up in 2017, by the National Association of Experts in PID (NAEPID). It is a secure, internet-based database that includes detailed clinical, laboratory, and therapeutic data on PID patients of all ages. Results: The registry contained information on 2,728 patients (60% males, 40% females), from all Federal Districts of the Russian Federation. 1,851/2,728 (68%) were alive, 1,426/1,851 (77%) were children and 425/1,851 (23%) were adults. PID was diagnosed before the age of 18 in 2,192 patients (88%). Antibody defects (699; 26%) and syndromic PID (591; 22%) were the most common groups of PID. The minimum overall PID prevalence in the Russian population was 1.3:100,000 people; the estimated PID birth rate is 5.7 per 100,000 live births. The number of newly diagnosed patients per year increased dramatically, reaching the maximum of 331 patients in 2018. The overall mortality rate was 9.8%. Genetic testing has been performed in 1,740 patients and genetic defects were identified in 1,344 of them (77.2%). The median diagnostic delay was 2 years; this varied from 4 months to 11 years, depending on the PID category. The shortest time to diagnosis was noted in the combined PIDs-in WAS, DGS, and CGD. The longest delay was observed in AT, NBS, and in the most prevalent adult PID: HAE and CVID. Of the patients, 1,622 had symptomatic treatment information: 843 (52%) received IG treatment, mainly IVIG (96%), and 414 (25%) patients were treated with biological drugs. HSCT has been performed in 342/2,728 (16%) patients, of whom 67% are currently alive, 17% deceased, and 16% lost to follow-up. Three patients underwent gene therapy for WAS; all are currently alive. Conclusions: Here, we describe our first analysis of the epidemiological features of PID in Russia, allowing us to highlight the main challenges around PID diagnosis and treatment.

Delay in the Diagnosis of APECED: A Case Report and Review of Literature from Iran

Autoimmune polyendocrinopathy candidiasis ectodermal dystrophy (APECED) syndrome is a rare monogenic autosomal recessive disorder caused by biallelic mutations in the AIRE (autoimmune regulator) gene. Patients with APECED present with heterogeneous endocrine and non-endocrine manifestations. In this study, we report an Iranian patient who presented with Addison disease, chronic mucocutaneous candidiasis, alopecia totalis, keratopathy and asplenia treated as an isolated endocrinopathy for 25 years. In the adulthood, the diagnosis of APECED was made by genetic analysis which demonstrated homozygous nonsense p.R257* (c.769C>T) mutation of AIRE. APECED has been shown to be frequent in some ethnicities including Iranian Jews. Therefore, we reviewed 39 Iranian APECED patients published in the literature. We found that most of the Iranian patients were of Jewish ethnic background and presented hypoparathyroidism, adrenal insufficiency, and candidiasis as the main clinical manifestation.

Lessons from primary immunodeficiencies: Autoimmune regulator and autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy

The discovery of the autoimmune regulator (AIRE) protein and the delineation of its critical contributions in the establishment of central immune tolerance has significantly expanded our understanding of the immunological mechanisms that protect from the development of autoimmune disease. The parallel identification and characterization of patient cohorts with the monogenic disorder autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED), which is typically caused by biallelic AIRE mutations, has underscored the critical contribution of AIRE in fungal immune surveillance at mucosal surfaces and in prevention of multiorgan autoimmunity in humans. In this review, we synthesize the current clinical, genetic, molecular and immunological knowledge derived from basic studies in Aire-deficient animals and from APECED patient cohorts. We also outline major advances and research endeavors that show promise for informing improved diagnostic and therapeutic approaches for patients with APECED.