Clinical aspects of 22q11.2 microdeletion syndrome

Introduction: The 22q11.2 microdeletion syndrome is the most common cause of DiGeorge syndrome, showing a wide phenotypic spectrum and has an estimated incidence of 1/4000–6000 livebirths. Objective: Detailed characterization of the clinical signs/symptoms associated with 22q11.2 deletion, estimation of the national incidence via establishing a Hungarian register. Method: Retrospective data between 2005 and 2019 from the 2nd Department of Paediatrics, Semmelweis University and from national database of congenital anomalies were obtained. Phenotypic abnormalities were described using the Human Phenotype Ontology nomenclature. Results: A cohort of 114 DiGeorge patients and 113 patients negative for FISH testing were included. The mean age of patients at diagnosis was 5.88 (± 9.66 SD) years and 54.9% of patients had at least one heart surgery until diagnosis. The main identified symptoms were ventricular septal defect, low-set ears, recurrent infections, high narrow palate and motor development delay. Discussion: The estimated incidence of DiGeorge syndrome in Hungary is 1/12 500 births, the frequency of infants at high risk and in need for surgery is high. Diagnosis is established 2–3 years earlier as compared to the international average. Conclusion: Based on the established Hungarian register, the incidence is lower compared to international data. In the case of conotruncal heart anomaly and ventricular septal defects, cytogenetic testing is recommended for the increased probability of DiGeorge syndrome. For second-tier testing, comparative genome hybridization or multiplex ligation-dependent probe amplification are recommended to identify atypical microdeletions. Newborns with DiGeorge syndrome require special care in perinatal intensive centers including pediatric cardiology and genetic counseling. Orv Hetil. 2022; 163(1): 21–30.