RIGI and obesity due to melanocortin 4 receptor deficiency: Interestingly, we observed a decreased expression of RIG-I and IFIH1, the MDA-5 protein precursor gene, in the placental tissue of the mothers with obesity (Figure 4A; p = 0.0249; p = 0.0108, respectively), compared to the non-obese group, during ZIKV infection.