BACKGROUNDA study of prenatal genetic diagnosis for 22q11.2 microdeletion, which has a wide phenotypic spectrum that involves almost all organs, is rarely reported in China. This study aimed to explore the prevalence of 22q11.2 microdeletion in congenitally malformed fetuses via the fluorescent in situ hybridization (FISH) technique and to investigate the feasibility of use of amniocytes to diagnose 22q11.2 microdeletion syndrome prenatally.

METHODSThe study enrolled 23 cases of fetal cardiac malformation, as indicated by ultrasound in Beijing Anzhen Hospital and 14 cases of non-cardiac malformation, as determined by type-B ultrasound in Beijing Anzhen Hospital and other hospitals. Amniotic fluid was obtained by amniocentesis before odinopoeia, and the stillborn fetuses of the induced labor were preceded to autopsy. The amniotic fluid of 20 cesarean deliveries during the same period of time was used as a control. The TUPLE1 gene in the amniotic fluid of malformed and normal fetuses was assessed by the FISH method.

RESULTSThe prevalence rates of the TUPLE1 gene deletion in the amniotic fluid cells from fetuses with cardiac deformations and fetuses without such malformations were 43.5% and 57.1%, respectively. The deletion of TUPLE1 was significantly associated with fetal malformation.

CONCLUSIONChromosome 22q11.2 microdeletion is one of the major factors leading to fetal congenital malformations, and prenatal FISH screening for 22q11.2 microdeletion syndrome is technically feasible using amniocytes.