Algerian Registry for Inborn Errors of Immunity in Children: Report of 887 Children (1985-2021).

INTRODUCTION: Inborn errors of immunity (IEI) represent a heterogeneous large group of genetic disorders characterized by susceptibility of affected individuals to recurrent infections, autoimmune/inflammatory diseases, allergy, and malignancy. We aimed to report for the first time the Algerian registry for IEI in children. METHODS: We described the characteristics of IEI in Algerian children from the data collected in the Algerian registry for IEI between 1985 and 2021. RESULTS: Over a period of 37 years, we included 887 children (530 male, 59.6%) with a mean age at diagnosis of 3.23 years and a mean diagnosis delay of 2 years. The prevalence rate was estimated at 1.97/100,000 inhabitants or 5.91/100,000 children. The parental consanguinity was found in 52.6%. The most prevalent category was combined immunodeficiencies (CID) (35.5%), followed by predominantly antibody deficiencies (24.5%) and CID with syndromic features (18.3%). The most predominant diseases were severe CID (134 cases), MHC II deficiency (99 cases), agammaglobulinemia (82 cases), common variable immunodeficiency (78 cases), hyper IgE syndromes (61 patients), ataxia-telangiectasia (46 patients), Wiskott-Aldrich syndrome (40 patients) and chronic granulomatous disease (39 cases). The clinical presentation was dominated by lower respiratory tract infections (69%), failure to thrive (38.3%), and chronic diarrhea (35.2%). Genetic analysis was performed in 156 patients (17.6%). The global mortality rate was 28.4% mainly caused by CID. CONCLUSION: This is the first report of the Algerian registry for IEI in children. Data is globally similar to that of the Middle East and North African (MENA) registries with high consanguinity, predominance of CID, and significant mortality. This registry highlights the weak points that should be improved in order to provide better patient care.

Consensus Middle East and North Africa Registry on Inborn Errors of Immunity.

BACKGROUND: Inborn errors of immunity (IEIs) are a heterogeneous group of genetic defects of immunity, which cause high rates of morbidity and mortality mainly among children due to infectious and non-infectious complications. The IEI burden has been critically underestimated in countries from middle- and low-income regions and the majority of patients with IEI in these regions lack a molecular diagnosis. METHODS: We analyzed the clinical, immunologic, and genetic data of IEI patients from 22 countries in the Middle East and North Africa (MENA) region. The data was collected from national registries and diverse databases such as the Asian Pacific Society for Immunodeficiencies (APSID) registry, African Society for Immunodeficiencies (ASID) registry, Jeffrey Modell Foundation (JMF) registry, J Project centers, and International Consortium on Immune Deficiency (ICID) centers. RESULTS: We identified 17,120 patients with IEI, among which females represented 39.4%. Parental consanguinity was present in 60.5% of cases and 27.3% of the patients were from families with a confirmed previous family history of IEI. The median age of patients at the onset of disease was 36 months and the median delay in diagnosis was 41 months. The rate of registered IEI patients ranges between 0.02 and 7.58 per 100,000 population, and the lowest rates were in countries with the highest rates of disability-adjusted life years (DALY) and death rates for children. Predominantly antibody deficiencies were the most frequent IEI entities diagnosed in 41.2% of the cohort. Among 5871 patients genetically evaluated, the diagnostic yield was 83% with the majority (65.2%) having autosomal recessive defects. The mortality rate was the highest in patients with non-syndromic combined immunodeficiency (51.7%, median age: 3.5 years) and particularly in patients with mutations in specific genes associated with this phenotype (RFXANK, RAG1, and IL2RG). CONCLUSIONS: This comprehensive registry highlights the importance of a detailed investigation of IEI patients in the MENA region. The high yield of genetic diagnosis of IEI in this region has important implications for prevention, prognosis, treatment, and resource allocation.