The Journal of Allergy and Clinical Immunology: In Practice
Review and Feature ArticleThe Diverse Clinical Features of Chromosome 22q11.2 Deletion Syndrome (DiGeorge Syndrome)
Section snippets
Key Phenotypic Features
The cardiac defects are generally apparent shortly after birth, and the repair of these anomalies is usually the most significant aspect of clinical care in the first few weeks of life.5 Another feature that can present in the first 1 or 2 weeks of life is hypocalcemia. Chromosome 22q11.2 deletion syndrome is the most common cause of congenital hypoparathyroidism, and prompt attention to the calcium levels as well as vitamin D replacement is warranted. Although conotruncal cardiac anomalies and
The Immune Deficiency
The basis for the phenotype of chromosome 22q11.2 deletion syndrome is the abnormal development of the third pharyngeal pouch. It can result in agenesis or hypoplasia of the parathyroid glands and the thymus. In very few patients, <1% with chromosome 22q11.2 deletion syndrome, the thymus and the T cells are absent, and this is referred to as complete DiGeorge syndrome. In 75% of patients, the immune system is affected to some degree, which leaves approximately 20% of patients with normal T-cell
Transplantation
Immune system reconstitution is essential for patients with complete DiGeorge syndrome and can be accomplished by 2 means, by thymus tissue transplantation or, alternatively, by a fully matched peripheral blood T-cell transplantation.50 As expected, hematopoietic cell transplantation does not result in ongoing T-cell lymphopoiesis with the majority having persistent CD4+ T-cell lymphopenia and a skewed T-cell receptor repertoire.51, 52 Although it is not clear if the lack of lymphopoiesis
Allergic and Autoimmune Disease
Allergic disease appears to be more common in patients with chromosome 22q11.2 deletion syndrome compared with the general population and could contribute to the increased frequency of upper respiratory infections,61 which may be explained by preferential differentiation of Th2 cells in the homeostatic expansion of T cells as has been observed in mice.62 Autoimmune disease is seen in approximately 10% of patients with deletion syndrome.17 Most commonly reported are hematologic autoimmune
The Opening Vignette
The immunologic evaluation of the 2-year-old boy described in the abstract demonstrated a low-for-age T-cell count (CD3), at 848 cells/mm3, with a CD4+ T-cell count of 573 cells/mm3. His naive-to-memory T-cell ratio was advanced, which had a higher proportion of memory T cells than expected for his age, but his quantitative immunoglobulin levels were normal as well as were antibody titers to pneumococcal, diphtheria, and tetanus vaccines. He was cleared to receive live viral vaccines and was
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2022, Forensic Science InternationalCitation Excerpt :In fact, the diagnosis of DGS is challenging because of the diversity of its clinical phenotype, especially for those without obvious malformations. According to the present studies, up to 50% of patients have ‘nontypical’ malformations and multiple phenotypes associated with 22q11.2 deficiency, including ophthalmology, genitourinary, endocrine, vascular and musculoskeletal disease [37]. A review of 54 patients with complete DGS reported that only 57% of the patients had congenital heart disease [38].
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2022, The Chromosome 22q11.2 Deletion Syndrome: A Multidisciplinary Approach to Diagnosis and TreatmentPulmonary Manifestations of Immunodeficiency and Immunosuppressive Diseases Other than Human Immunodeficiency Virus
2021, Pediatric Clinics of North AmericaCitation Excerpt :These disorders are characterized by defects of lymphocyte function and/or number, cytokine production, or immune activation, in association with characteristic clinical phenotypes or congenital anomalies. The presentation of this condition is often multisystemic, but cardiac and immune abnormalities are seen in more than 70% of patients.21 The immunologic defects are mainly related to variable thymic hypoplasia with lower than normal T-cell numbers, although normal T-cell proliferation is present in most patients.
Supported by the Wallace Chair of Pediatrics.
Conflicts of interest: The authors declare that they have no relevant conflicts of interest.
Cite this article as: Maggadottir SM, Sullivan KE. The diverse clinical features of chromosome 22q11.2 deletion syndrome (DiGeorge syndrome). J Allergy Clin Immunol Pract 2013;1:589-94. http://dx.doi.org/10.1016/j.jaip.2013.08.003.