Placental gene expression profiling for the identification of subtypes of human fetal growth restriction

Fetal growth restriction (FGR) is a heterogeneous disorder of pregnancy associated with pathologically low fetal and neonatal weights. We hypothesized that FGR consists of multiple placental subtypes, similar to what we have observed in preeclampsia. To address this hypothesis, we assembled a fetal growth-focused human placental microarray data set (N=97) consisting of 20 new normotensive suspected FGR samples (below), in addition to term controls (N=26) and hypertensive suspected FGR samples (N=51) from GSE75010. FGR was defined as an SGA infant (birthweight <10th percentile for gestational age and sex based on a Canadian growth reference) with signs of placental insufficiency, and 20 normotensive suspected FGR placentas were purchased from a biobank. Genome-wide mRNA expression was assessed by Affymetrix Human Gene 1.0 ST Array chips and aggregated with samples from GSE75010. Unsupervised clustering analysis was applied to the combined dataset (N=97), followed by pathway enrichment analysis and correlative analysis with clinical information and histological lesions in these placentas.