[22q11.2 deletion syndrome and complex congenital heart defects]

Area of Science:

• Genetics
• Pediatric Cardiology
• Medical Diagnostics

Context:

• Complex congenital heart disease (CCHD) affects numerous infants, often associated with genetic syndromes.
• 22q11 deletion syndrome (22q11DS) is a known genetic cause of CCHD, but its precise frequency in specific CCHD subtypes requires further elucidation.
• Accurate diagnosis of 22q11DS is crucial for appropriate patient management and genetic counseling.

Purpose:

• To determine the prevalence of 22q11DS in a cohort of pediatric patients diagnosed with complex congenital heart defects.
• To assess the association between specific types of congenital heart defects, particularly conotruncal malformations, and the presence of 22q11DS.
• To evaluate the diagnostic yield of fluorescence in situ hybridization (FISH) for detecting 22q11DS in this patient population.

Summary:

• A prospective study evaluated 66 pediatric patients with complex heart defects. High-resolution karyotyping and FISH analysis for 22q11 microdeletion were performed.
• Overall, 22q11 microdeletion was identified in 2 out of 65 patients (3.1%). In patients with conotruncal malformations (n=52), the frequency of 22q11DS was 3.9% (2 out of 51).
• The identified cases of 22q11DS presented with tetralogy of Fallot, a type of conotruncal malformation.

Impact:

• This research underscores that 22q11DS is a significant genetic abnormality in children with complex and conotruncal heart defects.
• The findings suggest that genetic screening for 22q11DS should be considered in pediatric patients presenting with these cardiac conditions.
• Variability in reported 22q11DS frequencies across studies may be attributed to differences in patient selection criteria and population characteristics.