SPARC and obesity due to melanocortin 4 receptor deficiency: This family includes molecules, such as SPARC, SPARCL-like 1 (SPARCL1), thrombospondin 1 and 2, and osteopontin, all of which have been implicated in the development of obesity, insulin resistance, and chronic liver diseases (Bai et al., 2020; Icer and Gezmen-Karadag, 2018; Kos and Wilding, 2010).