Case of late diagnosis of DiGeorge syndrome (22q11.2 deletion syndrome) in a patient with chronic nonspecific lung diseases

Abstract

   Introduction. DiGeorge syndrome (22q11.2 deletion) is a genetic disorder characterized by wide phenotypic polymorphism. Its main manifestations include congenital heart defects, immunodeficiency due to thymic hypoplasia, and hypocalcemia resulting from parathyroid gland dysfunction. High variability of clinical combinations often masks the syndrome as transsyndromic comorbidity, substantially complicating its timely verification.    Aim. To describe a clinical case of incomplete 22q11.2 deletion syndrome (DiGeorge syndrome) diagnosed in a 15-year-old patient with chronic nonspecific lung diseases, in order to familiarize physicians with the clinical features of the disease and current diagnostic capabilities.    Materials and methods. A retrospective analysis of the medical record of a patient followed up at the Khabarovsk Branch of the Far Eastern Scientific Center of Physiology and Pathology of Respiration – Research Institute of Maternity and Child Protection was performed.    Results. A rare genetic pathology – incomplete form of DiGeorge syndrome – is described. Disease manifestation occurred at the age of seven months. The clinical picture developed against the background of a congenital malformation of the respiratory organs and was characterized by a complicated pulmonological history (recurrent pneumonia, bronchial asthma). The patient was also diagnosed with thymic hypoplasia, selective immunoglobulin A deficiency, relative T-helper cell deficiency, and hypoparathyroidism. The diagnosis was verified only at the age of 15 years based on whole-genome sequencing results, which revealed a heterozygous deletion of the 22q11.2 region.    Conclusion. This case report demonstrates the difficulty of timely detection of the incomplete form of DiGeorge syndrome in the absence of early molecular genetic screening.