Our second representative case was a female patient with osteosarcoma, diagnosed at 10, who carried a pathogenic variant in GJB2 in addition to a germline duplication of DDX10, the latter, a known marker somatically associated with poor prognosis for osteosarcoma (Table 1; Fig. 1c; Supplementary Fig. 3a). Here, GJB2 is linked to osteosarcoma.