Replication of a genome-wide association study of birth weight in preterm neonates

OBJECTIVE: To examine associations in a preterm population between rs9883204 in ADCY5 and rs900400 near LEKR1 and CCNL1 with birth weight. Both markers were associated with birth weight in a term population in a recent genome-wide association (GWA) study by Freathy et al. STUDY DESIGN: A meta-analysis of mother and infant samples was performed for associations of rs900400 and rs9883204 with birth weight in 393 families from the U.S., 265 families from Argentina and 735 mother-infant pairs from Denmark. Z scores adjusted for infant sex and gestational age were generated for each population separately and regressed on allele counts. Association evidence was combined across sites by inverse-variance weighted meta-analysis. RESULTS: Each additional C allele of rs900400 (LEKR1/CCNL1) in infants was marginally associated with a 0.069 standard deviation (SD) lower birth weight (95% CI = −0.159 – 0.022, P = 0.068). This result was slightly more pronounced after adjusting for smoking (P = 0.036). There were no significant associations identified with rs9883204 or in maternal samples. CONCLUSIONS: These results indicate the potential importance of this marker on birth weight irrespective of gestational age