Prenatal diagnosis of 22q11.2 deletion syndrome in two consecutive pregnancies: a case report / 中华围产医学杂志

ABSTRACT

This article reports the prenatal diagnosis of 22q11.2 deletion syndrome (22q11.2 DS) in two consecutive pregnancies of a woman. Echocardiography on the first fetus at 24 +4 gestational weeks identified the right aortic arch, and right-sided ductus arteriosus with aberrant left subclavian artery. Subsequently, an amniocentesis was performed, and chromosomal microarray analysis (CMA) of amniotic fluid revealed a 2.181 Mb heterozygous microdeletion of 22q11.21, which indicated the presence of 22q11.2 DS in the fetus. After genetic counseling, the pregnant woman decided to terminate the pregnancy and declined genetic testing. During her second pregnancy, ultrasound at 21 +5 weeks detected interrupted aortic arch type B with aberrant left subclavian artery, ventricular septal defect, and enlarged posterior fossa in the fetus and further CMA of amniotic fluid indicated fetal 22q11.2 DS. CMA was performed on peripheral blood of the woman, which found the same deletion on 22q11.21. The woman had nasal sounds and velopharyngeal insufficiency with normal phenotype. Following the genetic counseling regarding the risk of recurrence, the pregnant woman opted to terminate the pregnancy and was suggested to undergo preimplantation genetic diagnosis in future pregnancies. One year after the second pregnancy termination, the woman's father developed heart failure at the age of 53 and was also found to have nasal sounds. Low-depth whole genome copy number variation sequencing in venous blood confirmed 22q11.2 DS in her father. For those with a prenatal diagnosis of 22q11.2 DS, genetic testing of the fetal parents is recommended to help assess the risk of recurrence and facilitate genetic counseling.