SPARC and obesity due to melanocortin 4 receptor deficiency: However, recent studies have revealed pathologic roles for SPARC in adulthood, such as adipose fibrosis, age‐related inflammation, metabolic dysfunction, obesity, and diabetes and diabetic nephropathy and retinopathy (Kos and Wilding 2010; Xu et al. 2013; Ryu et al. 2022).