Chapter 3 - Combined immunodeficiencies with associated or syndromic features

Abstract

Combined immune deficiencies (CIDs) are a heterogeneous group of inherited immune disorders characterized by impaired development, function, or both of T lymphocytes, with variable B cell defects. Among CIDs, a group of disorders is associated with syndromic features. The term CID syndromes apply to disorders in which other clinical features are present in addition to immunodeficiency. CID with associated or syndromic features comprises nine major categories including congenital thrombocytopenia, DNA repair defects, immunoosseous dysplasias (IODs), thymic defects with additional congenital anomalies, hyper-immunoglobulin E syndromes, dyskeratosis congenital, defects of vitamin B12 and folate metabolism, anhidrotic epidermodysplasia with ID and others. Most patients belonging to this group of primary immunodeficiency disorders manifest severe infections caused by opportunistic organisms, chronic diarrhea, failure to thrive, and recurrent and chronic respiratory infections. These patients present with less severe complications in the first year of life than severe CID patients, as evidence of immunodeficiency may be initially absent, whereas other clinical complications are present. Because syndromic CID can present initially with nonimmunologic manifestation, the various medical specialists involved in these cases should be aware of the signs and symptoms of this PID category.