A recent nationwide genomic analysis conducted in Japan for undiagnosed diseases (Initiative on Rare and Undiagnosed Diseases; IRUD) identified the frameshift variant, c.119_120del, p.(Ser40Phefs*2), in the KNTC1 gene of a woman diagnosed with ovarian cancer with histology of adenocarcinoma (hereafter referred to as ‘the patient’). The gene discussed is KNTC1; the disease is ovarian cancer.