Despite a strong association between POU5F1/OCT4 and HNF1A mRNA levels, we did not observe a significant association between POU5F1/OCT4 mRNA and any of the PDA subpopulations, indicating that factors other than HNF1A modulate the levels of POU5F1/OCT4 mRNA in different PDA subpopulations (data not shown). Here, HNF1A is linked to Patent ductus arteriosus.