SMAD3 and osteoarthritis, hip: In addition, the HSM4 and hip osteoarthritis GWAS signals around rs12901499 colocalised with each other (PP 99%) and the HSM4 GWAS signal colocalised with SMAD3 mRNA expression in both healthy and degraded human cartilage (PP 98% in both tissues, Supplementary Table 13, Supplementary Figs. 13 and 14).