To further identify the clinical significance of SLC3A2 level in OA, we first detected the relative RNA expression of SLC3A2 in the cartilage of the damaged area and undamaged area in 30 OA patients (Figure 6a) and then used the Sankey diagram to visualize the relationships between the expression level of SLC3A2 in the damaged area and clinical factors, including age, gender, obesity grade, K-L grade (Figure 6b,c). The gene discussed is SLC3A2; the disease is obesity due to melanocortin 4 receptor deficiency.