Definition for View source for Li-Fraumeni syndrome

Li–Fraumeni syndrome is an extremely rare autosomal dominant hereditary disorder. Named after Frederick Pei Li and Joseph F. Fraumeni, Jr., the American physicians who first recognized and described the syndrome, Li–Fraumeni syndrome greatly increases susceptibility to cancer. This syndrome is also known as the Sarcoma, breast, leukaemia and adrenal gland (SBLA) syndrome.

The syndrome is linked to germline mutations of the TP53 tumor suppressor gene, which normally helps control cell growth. The mutations can be inherited or can arise de novo early in embryogenesis or in one of the parent's germ cells.

The TP53 gene is responsible for initiating DNA repair mechanisms and/or apoptosis upon detection of DNA damage." P53 is a dominant negative mutation, so the mutant protein can inactivate the normal protein, meaning the mutant protein is dominant. Because of this, Li–Fraumeni syndrome, with one of the two p53 copies already mutated, predisposes a person to cancer development. Persons with Li–Fraumeni syndrome have an approximately 25-fold increased risk of developing a malignant tumor by age 50 than the population average, and are at risk for a wide range of malignancies, with particularly high occurrences of breast cancer, brain tumors, acute leukemia, soft tissue sarcomas, bone sarcomas, and adrenal cortical carcinoma.