Prenatal Diagnosis of 22q11.2 Deletion Syndrome Using Fluorescence <i>In Situ</i> Hybridization (FISH)

Objectives: 22q11.2 deletion syndrome (22q11.2DS), also known as DiGeorge or velocardiofacial syndrome, is the most common chromosomal microdeletion disorder in humans. Prenatal detection is critical for pregnancy management, as affected individuals may present with congenital heart defects, immune dysfunction, craniofacial anomalies, developmental delay, and neuropsychiatric disorders. Material and Methods: A retrospective study was conducted from January 21 to June 24 on 70 pregnancies with suspected congenital structural heart defects. Fluorescence in situ hybridization (FISH) analysis was performed on amniotic fluid samples using a DiGeorge syndrome specific probe targeting the 22q11.2 region, following the manufacturer’s instructions. At least, 30 interphase nuclei were evaluated per case. Results: Conventional cytogenetic analysis revealed normal karyotypes in all 70 cases. However, FISH analysis detected 22q11.2 microdeletions in 3 cases (4.3%). These findings align with previous reports indicating a significant association between conotruncal cardiac anomalies and 22q11.2 deletions. Conclusion: FISH is a rapid, specific, and reliable technique for the prenatal detection of 22q11.2DS, particularly in pregnancies at risk. While it does not provide information on deletion size or detect other chromosomal abnormalities, it remains an invaluable diagnostic tool when combined with comprehensive genetic counseling. Early identification enables timely medical planning and psychosocial support, ultimately improving perinatal outcomes.