[Placental PHLDA2 gene imprinting in patients with pre-eclampsia]

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.

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.

No heterozygote was found in placental tissues in relation to C/T polymorphism in PHLDA2 exon 1. Differences in heterozygote in relation to G/A polymorphism in PHLDA2 exon 2 were found between pre-eclampsia (4/19) and normal pregnancy(5/21), but without statistical significance. PHLDA2 cDNA from heterozygotes (PHLDA2-2) were all exclusively monoallelically expressed.

Similargene polymorphism of PHLDA2 (PHLDA2-1 and PHLDA2-2) in placental tissues was found between pre-eclampsia and normal pregnancies. No loss of imprinting (LOI) of PHLDA2 was found in this study.