Placental PHLDA2 Gene Imprinting in Patients with Pre-eclampsia

Objective To observe the imprinting status of maternally expressed gene pleckstrin homology-like domain, family A, member 2 (PHLDA2) in placental tissues from patients with pre-eclampsia. Methods Samples of placental tissues were collected from women with normal pregnancy (n=21) and pre-eclampsia (n=19). We examined two single nucleotide polymorphism (SNPs) which are prone to variation in PHLDA2: the C/T polymorphism in exon 1 and the G/A polymorphism in exon 2, corresponding to rs13390 (PHLDA2-1) and rs1056819 (PHLDA2-2), respectively. DNA PCR-direct sequencing and cDNA RT-PCR-direct sequencing were applied to detect the special-allelic imprinting status of PHLDA2. Results No heterozygote was found in placental tissues in relation to C/T polymorphism in PHLDA2exon 1.Differences in heterozygote in relation to G/A polymorphism in PHLDA2 exon 2 were found betweenpre-eclampsia(4/19) and normal pregnancy(5/21), but without statistical significance. PHLDA2 cDNA from heterozygotes (PHLDA2-2) were all exclusively monoallelically expressed. Conclusion Similargene polymorphism of PHLDA2 (PHLDA2-1 and PHLDA2-2) in placental tissues was found between pre-eclampsiaand normal pregnancies.No loss of imprinting (LOI) of PHLDA2 was found in this study.