HIF1A and osteochondritis dissecans: However, we showed that in fibroblasts from probands with germline variants in VHL (Proband 12), IDH2 (Proband 17), KDM4C (Proband 18), and CDKN2A (Proband 21), the expression of HIF-1 regulated genes is impaired under hypoxia, supporting the role of variants at these loci in the pathogenesis of OD and MS.