Prenatal cardiac findings and 22q11.2 deletion syndrome: Fetal detection and evaluation

Abstract

Clinical features of 22q11.2 microdeletion syndrome (22q11.2DS) are highly variable between affected individuals and frequently include a subset of conotruncal and aortic arch anomalies. Many are diagnosed with 22q11.2DS when they present as a fetus, newborn or infant with characteristic cardiac findings and subsequently undergo genetic testing. The presence of an aortic arch anomaly with characteristic intracardiac anomalies increases the likelihood that the patient has 22q11.2 DS, but those with an aortic arch anomaly and normal intracardiac anatomy are also at risk. It is particularly important to identify the fetus at risk for 22q11.2DS in order to prepare the expectant parents and plan postnatal care for optimal outcomes. Fetal anatomy scans now readily identify aortic arch anomalies (aberrant right subclavian artery, right sided aortic arch or double aortic arch) in the three-vessel tracheal view. Given the association of 22q11.2DS with aortic arch anomalies with and without intracardiac defects, this review highlights the importance of recognizing the fetus at risk for 22q11.2 deletion syndrome with an aortic arch anomaly and details current methods for genetic testing. To assist in the prenatal diagnosis of 22q11.2DS, this review summarizes the seminal features of 22q11.2DS, its prenatal presentation and current methods for genetic testing.

FIGURE 1

Low copy repeats and genes within the 22q11.2 deletion.

FIGURE 2

Prevalence of different cardiac defects in 22q11.2 deletion syndrome.

FIGURE 3

Concurrent aortic arch anomalies with intracardiac defect increase the likelihood of 22q11.2DS. Aortic arch anomalies in addition to intracardiac defects increases the likelihood that a patient has 22q11.2 deletion syndrome. Arch anomaly, left sided aortic arch with aberrant right subclavian artery or right sided aortic arch with any branching pattern; IAA-B, interrupted aortic arch type B; LAA-nl branch, normal left sided aortic arch with normal branching pattern; TA, truncus arteriosus; TOF, tetralogy of Fallot; VSD, conoventricular septal defect.