FLT1 and obesity due to melanocortin 4 receptor deficiency: Moreover, risk factors are considered the genetic predisposition, such as mutations in the fms related receptor tyrosine kinase 1 (FLT1) gene and trisomy 13, immunological abnormalities, such as imbalance between decidual natural killers and regulatory T cells, maternal comorbidities—such as diabetes, obesity, and chronic kidney disease, in vitro fertilization, as well as older maternal age [167,168].