KRT4 and obesity due to melanocortin 4 receptor deficiency: Therefore, the lipoma-like Tg(krt4:Hsa.myrAkt1)cy18 reported in this study serves as a good disease model for modeling obesity-induced chronic disease according to the following phenotypic signatures: a great increase in weight gain (Figs. 4A and 4B) and whole body triglyceride content (Table 1), a symptom of muscle contraction weakness (Fig. 8B) and osteoporosis by adipocyte infiltration (Fig. 5J), high neutrophil infiltration (Fig. 6E), glucose intolerance (Fig. 7), and short life span (Fig. 8C).