Previously proposed skeletal complication (such as osteonecrosis, bone damage, or metabolic changes in bone tissue) biomarkers in GD1 according to the literature were primarily chemokines: C-C motif chemokine 3 (CCL3 gene, MIP-1α), cathepsin K (CTSK gene), C-C motif chemokine 4 (CCL4 gene, MIP-1β), osteocalcin (BGLAP gene), interleukin-8 (CXCL8 gene), C-C motif chemokine 18 (CCL18 gene) and C-C motif chemokine 5 (CCL5 gene). The gene discussed is CTSK; the disease is osteonecrosis.