Prenatal diagnosis of interruption of the aortic arch and its association with deletion of chromosome 22q11

Abstract

Differentiation of interruption of the aortic arch (IAA) type A from type B by prenatal echocardiography is possible but difficult. We report nine consecutive cases of the prenatal detection of IAA and evaluate the feasibility of making a correct prenatal diagnosis with fetal echocardiography. The incidence of 22q11 microdeletion in our series, detected using fluorescent in situ hybridization (FISH) analysis, was determined. Echocardiography and FISH for the DiGeorge critical region (22q11) were performed in all cases. The findings were confirmed by autopsy (three cases) or at postnatal surgery (six cases). On fetal echocardiography we identified six type B cases and three type A. FISH detected microdeletions in 22q11 in five of nine fetuses (four type B cases and an unusual association with type A in one case). Our report confirms the feasibility of making a correct prenatal diagnosis of IAA and its different types, based on echocardiographic examination. Furthermore our data are consistent with previous reports indicating that type A and type B are distinct entities. In more than 50% of fetuses with IAA type B, 22q11 microdeletion and DiGeorge or velo-cardio-facial syndromes may be expected. IAA type A is not commonly associated with 22q11 hemizygosity.