There were no cancers observed either among the 31 IC1-GOM patients (268.9 PY; 0.0449 cases expected), the 12 duplication/deletion patients or the six patients with a pathogenetic variant in CDKN1C. The cancer risk up to the 15th birthday was 4.4% in the entire cohort, 17.6% for patients with UPDpat and 1.6% for patients with IC2-LOM. The gene discussed is CDKN1C; the disease is cancer.