ABSTRACT: BACKGROUND: Babies born at lower gestational ages or smaller birthweights have a greater risk of poorer health in later life. Both the causes of these sub-optimal birth outcomes and the mechanism by which the effects are transmitted over decades are the subject of extensive study. We investigated whether a transcriptomic signature of either birthweight or gestational age could be detected in umbilical cord RNA. METHODS: The gene expression patterns of 32 umbilical cords from Singaporean babies of Chinese ethnicity across a range of birthweights (BW, 1698-4151g) and gestational ages (GA, 35-41 weeks) were determined. We confirmed the differential expression pattern by gestational age for 12 genes in a series of 127 umbilical cords of Chinese, Malay and Indian ethnicity. RESULTS: We found that the transcriptome is substantially influenced by gestational age; but less so by birthweight. We show that some of the expression changes dependent on gestational age are enriched in signal transduction pathways, such as Hedgehog and in genes with roles in cytokine signalling and angiogenesis. We show that some of the gene expression changes we report are reflected in the epigenome. CONCLUSIONS: We studied the umbilical cord which is peripheral to disease susceptible tissues. The results suggest that soma-wide transcriptome changes, preserved at the epigenetic level, may be a mechanism whereby birth outcomes are linked to the risk of adult metabolic and arthritic disease and suggest that greater attention be given to the association between premature birth and later disease risk. 8 umbilical cords form low birth weight babies, 8 umbilical cords from high birth weight babies, 14 umbilical cords from normal birth weigth babies, 7 matching the gestational ages of the low birth weigth group (norm1) and 7 matching the getsational ages of the high birth weight group (norm2). Replicates for array, cRNA and slide spotting REPLICATES: biological replicate: LBW_1, LBW_2, LBW_3A, LBW_3B, LBW_3C, LBW_4, LBW_5, LBW_6, LBW_7, LBW_8A, LBW_8B biological replicate: HBW_1, HBW_2A, HBW_2B, HBW_2C, HBW3, HBW4, HBW5, HBW6, HBW7, HBW8 biological replicate: norm1_1, norm1_2, norm1_3, norm1_4, norm1_5, norm1_7A, norm1_7B, norm1_7C, norm1_7D biological replicate: norm2_1, norm2_2, norm2_3, norm2_4, norm2_5, norm2_6A, norm2_6B, norm2_7 technical replicate: HBW_2A, HBW_2B, HBW_2C technical replicate: LBW_3A, LBW_3B, LBW_3C technical replicate: LBW_8A, LBW_8B techical replicate: norm1_7A, norm1_7B, norm1_7C, norm1_7D technical repliacte: norm2_6A, norm2_6B
