Alterations of PHOX2B function is associated with a wide range of diseases, including congenital central hypoventilation syndrome (CCHS) and neural crest-derived tumors, from low-grade (ganglioneuromas) to malignant forms (neuroblastomas). We report a case bearing a novel nonpolyalanine repeat PHOX2B pathogenic variant presenting both as high-risk neuroblastoma and late-onset CCHS. CCHS was revealed upon severe respiratory decompensation while the patient was administered the anti-GD2 antibody dinutuximab-beta, as part of neuroblastoma treatment. From this experience, we make propositions for the management of patients with high-risk neuroblastoma and a constitutional pathogenic variant of PHOX2B.