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Li-Fraumeni syndrome is a rare disorder that greatly increases the risk of developing several types of cancer, particularly in children and young adults.
The cancers most often associated with Li-Fraumeni syndrome include breast cancer, a form of bone cancer called osteosarcoma, and cancers of soft tissues (such as muscle) called soft tissue sarcomas. Other cancers commonly seen in this syndrome include brain tumors, cancers of blood-forming tissues (leukemias), and a cancer called adrenocortical carcinoma that affects the outer layer of the adrenal glands (small hormone-producing glands on top of each kidney). Several other types of cancer also occur more frequently in people with Li-Fraumeni syndrome.
A very similar condition called Li-Fraumeni-like syndrome shares many of the features of classic Li-Fraumeni syndrome. Both conditions significantly increase the chances of developing multiple cancers beginning in childhood; however, the pattern of specific cancers seen in affected family members is different.
The exact prevalence of Li-Fraumeni is unknown. One U.S. registry of Li-Fraumeni syndrome patients suggests that about 400 people from 64 families have this disorder.
The CHEK2 and TP53 genes are associated with Li-Fraumeni syndrome.
More than half of all families with Li-Fraumeni syndrome have inherited mutations in the TP53 gene. TP53 is a tumor suppressor gene, which means that it normally helps control the growth and division of cells. Mutations in this gene can allow cells to divide in an uncontrolled way and form tumors. Other genetic and environmental factors are also likely to affect the risk of cancer in people with TP53 mutations.
A few families with cancers characteristic of Li-Fraumeni syndrome and Li-Fraumeni-like syndrome do not have TP53 mutations, but have mutations in the CHEK2 gene. Like the TP53 gene, CHEK2 is a tumor suppressor gene. Researchers are uncertain whether CHEK2 mutations actually cause these conditions or are merely associated with an increased risk of certain cancers (including breast cancer).
Li-Fraumeni syndrome is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to increase the risk of developing cancer. In most cases, an affected person has a parent and other family members with cancers characteristic of the condition.
'''Li-Fraumeni syndrome''' is a rare autosomal dominant hereditary disorder. It is named after Frederick Pei Li and Joseph F. Fraumeni, who originally described the syndrome. It greatly increases susceptibility to cancer. The syndrome is a mutation in the p53 tumor suppressor gene, which normally helps control cell growth.