Other potential genes that were studied in patients with DISH and chondrocalcinosis (DISH/CC) include R-spondin 4 (RSPO4), LEM domain-containing 3 (LEMD3), and protein phosphatase 2 regulatory subunit beta delta 2 (PPPR2RD) (Table 1, Figure 1) [13,14]. The gene discussed is RSPO4; the disease is diffuse idiopathic skeletal hyperostosis.