TTR and obesity due to melanocortin 4 receptor deficiency: Indeed, genes involved in retinol and lipoprotein transport were suppressed, and RNA in situ hybridization confirmed reduced expression of retinol transporters Ttr, Rbp4, and Stra6, and lipoprotein transporter Apoa1 in visceral yolk sac.<h4>Conclusion</h4>Obesity during pregnancy causes early transcriptional dysregulation that impairs retinoic acid and lipoprotein transport at the maternal-fetal interface, suggesting a mechanism through which maternal obesity could influence long-term developmental outcomes.