Objective: To ascertain the frequency of 22q11 deletions in a represen
tative population of conotruncal heart defects (CTD) and determine whi
ch children are at risk of having a deletion. Methodology: A clinical
and laboratory evaluation of 90 children with CTD, including isolated
and syndromic cases. Results: Fifteen children (17%) were shown to hav
e 22q11 deletions by fluorescence in situ hybridization (FISH) studies
with the Oncor probe N25. Varying degrees of developmental delay/lear
ning disabilities and facial dysmorphism were common in these children
. None of the isolated cases without dysmorphism had a deletion. Concl
usion: 22q11 deletions are a significant cause of a specific form of c
ongenital heart disease, CTD. It is important to have a high index of
suspicion of the 22q11 deletion disorders in children with CTD and oth
er extracardiac manifestations so that the diagnosis can be made early
and appropriate interventions implemented.