Prenatal diagnosis of a fetus with mosaic trisomy 2 and uniparental disomy of chromosome 2 / 中华围产医学杂志

ABSTRACT

This paper presented the prenatal genetic analysis of a case of mosaic trisomy 2 combined with uniparental disomy 2. The pregnant women underwent non-invasive prenatal testing in Zhuhai Center for Maternal and Child Health Care on February 2019, which indicated an increased number of chromosome 2. Subsequently, amniocentesis was performed at 21 +2 weeks for prenatal diagnosis. No abnormalities were detected through the karyotype analysis of amniotic fluid cells. Chromosome microarray analysis of uncultured amniotic fluid cells revealed a duplication of 2.3 copies in chromosome 2 and 64.3 Mb regions of homozygosity in the 2q21.2q33.1 region. The comparison of single nucleotide information on fetus-parent chromosome 2 showed that the regions of homozygosity of the fetal 2q21.2q33.1 was paternal uniparental isodisomy (2), with the rest of chromosome 2 being paternal uniparental heterodisomy (2).Ultrasound results at 27 +6, 31 +6, and 34 +5 weeks of gestation showed continued exacerbation of fetal growth retardation with placental abnormalities and fetal blood flow spectrum abnormalities. Due to threatened preterm delivery at 35 +3 weeks, The pregnant woman chose to give up the fetus and delivered a stillbirth.