Aim: Differences in children's development and susceptibility to diseases and exposures have been observed by sex, yet human studies of sex differences in miRNAs are limited.
Materials & methods: The genome-wide miRNA expression was characterized by sequencing-based EdgeSeq assay in cord blood buffy coats from 89 newborns, and 564 miRNAs were further analyzed.
Results: Differential expression of most miRNAs was higher in boys. Neurodevelopment, RNA metabolism and metabolic ontology terms were enriched among miRNA targets. The majority of upregulated miRNAs (86%) validated by nCounter maintained positive-fold change values; however, only 21% reached statistical significance by false discovery rate.
Conclusion: Accounting for host factors like sex may improve the sensitivity of epigenetic analyses for epidemiological studies in early childhood.
Keywords: cord blood; early life; epigenetics; filtering; miRNA; miRNAome; newborns; next-generation sequencing; normalization procedures; sex differences.