Pregnancy with de novo 9q34.3 microdeletion and Kleefstra syndrome in the fetus may be associated with an abnormal maternal serum screening result

摘要

A 32-year-old, primigravid woman underwent amniocentesis in the second trimester due to an abnormal maternal serum screening result of a Down syndrome risk of 1/44 calculated from a level of 0.78 multiples of the median (MoM) of α-fetoprotein (AFP), a level of 3.05 MoM of free β-human chorionic gonadotrophin (β-hCG), a level of 2.66 MoM of inhibin A, and a level of 0.98 MoM of unconjugated estriol (E3) at 15 weeks of gestation. Amniocentesis revealed a karyotype of 46,XY. Prenatal ultrasound findings were unremarkable, and the pregnancy was uneventful. A male baby was delivered smoothly at term with a body weight of 3674 g and a body length of 49 cm. The infant postnatally manifested characteristic facial appearance of Kleefstra syndrome, intellectual disability, and developmental delay. Array comparative genomic hybridization (aCGH) analysis of the peripheral blood revealed an 8.08-kb 9q34.3 microdeletion or arr 9q34.3 (140,687,823–140,695.906)×1 encompassing an OMIM gene of EHMT1 consistent with the diagnosis of Kleefstra syndrome.