Aim. The aim of this study was to identify genetic causes of a hereditary cancer in Ukrainian pedigree. Conclusions. The efficacy of next-generation sequencing for the diagnosis of hereditary cancers was exemplified using a familial case with a dual genetic predisposition for cancer. It was determined that the P's son, who is 25 years of age, is a carrier of the MSH6 c.2150_2153del mutation. With the implementation of proper monitoring planning and a responsible attitude on the part of the patient, an early diagnosis strategy can be implemented, which will result in the potential cancer being diagnosed at an early stage.