DiGeorge Syndrome: Assessment of Thymic Aplasia, Immunodeficiency, and Differentiation of Hypoparathyroidism in 22q11 Deletion

The DiGeorge syndrome, also known as 22q11 deletion, is a genetic disorder characterized by a wide range of clinical manifestations, including immunodeficiency and hypoparathyroidism. This syndrome results from a microdeletion on chromosome 22, specifically in the 22q11.2 region, affecting the development of structures derived from the pharyngeal arches during embryogenesis. The estimated prevalence is 1 in every 4,000 to 6,000 live births.

Diving Deeper into DiGeorge Syndrome

The DiGeorge syndrome presents significant phenotypic variability, which can complicate its early diagnosis. The most common features include congenital heart defects, hypocalcemia due to hypoparathyroidism, and immunodeficiency caused by thymic aplasia or hypoplasia. The absence or hypoplasia of the thymus is particularly concerning, as this organ is crucial for the development of T lymphocytes, essential for an adequate immune response. In severe cases, complete absence of the thymus can lead to a form of severe combined immunodeficiency (SCID) [1].

The assessment of immunodeficiency in patients with this syndrome is fundamental. The implementation of T-cell receptor excision circles (TRECs) evaluation in newborn screening has improved the early detection of the 22q11.2 deletion syndrome, allowing for timely intervention [2]. Additionally, the hypocalcemia resulting from hypoparathyroidism can be managed with calcium and vitamin D supplements, although in some cases, correcting hypoparathyroidism may be more complex [3].

Conclusions

Management of DiGeorge syndrome requires a multidisciplinary approach that includes pediatrics, immunology, cardiology, and endocrinology, among other specialties. Early identification and appropriate management of immunological and endocrine complications are crucial for improving long-term outcomes in these patients. The variability in clinical presentation underscores the importance of accurate diagnosis and ongoing follow-up [4].

Referencias

• [1] DiGeorge Syndrome
• [2] Chromosome 22q11.2 Deletion (DiGeorge Syndrome): Immunologic Features, Diagnosis, and Management
• [3] Correction of both immunodeficiency and hypoparathyroidism by thymus transplantation in complete DiGeorge syndrome
• [4] Clinical and Immunological Defects and Outcomes in Patients with Chromosome 22q11.2 Deletion Syndrome

Created 13/1/2025