However, in a study of a family with the complex genotype p.Gln792Ser‐p.Glu668Lys‐p.Leu611Val, functional testing of NPP activity for SaSO2 osteosarcoma cell lines bearing the missense variant p.Glu668Lys were normal and the patient's phenotype was therefore attributed to the p.Leu611Val variant (Rutsch et al., 2003). The gene discussed is POMC; the disease is osteosarcoma.