PDGFRA and obesity due to melanocortin 4 receptor deficiency: Subsequent studies including both male and female animals will be required to determine whether any aspects of obesity-associated diaphragm remodeling or FAP complement are sexually dimorphic (81) — a critical issue given recent reports of estradiol signaling to promote pro-fibrotic responses in Pdgfra-expressing mesenchymal cells of the abdominal wall musculature (82).