A novel, unstable DNA mutation cracks decades-old clinical enigma
Article Abstract:
A new type of genetic mutation may cause fragile X syndrome, myotonic dystrophy and Kennedy disease. This mutation involves a continuous repetition of the same three nucleotides, in the same order, in a sequence of DNA on a gene. Several hundred to more than a thousand of these repeat sequences occur in patients with fragile X syndrome, myotonic dystrophy or Kennedy disease. Increased numbers of these sequences create areas of instability characterized by ongoing genetic change in successive generations. Some individuals may have increased numbers of these sequences without developing a genetic disease, but their children suffer from a severe form of the disorder. An increase in severity and an earlier age of onset may be associated with an increased number of repeat sequences. Physicians have noticed since the early 1900s that certain genetic disorders may increase in severity through successive generations of the same family.
Publication Name: JAMA, The Journal of the American Medical Association
Subject: Health
ISSN: 0098-7484
Year: 1993
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Family tree can yield lifesaving knowledge for patients at risk for hereditary cancers
Article Abstract:
Individuals may learn more about their risk of inheriting certain types of cancer by examining their family tree. Between 5% and 10% of patients who develop cancer may have an inherited form of the disease. Hereditary cancer often occurs earlier in life and follows the laws of classic Mendelian genetics. Henry Lynch of Creighton University's Hereditary Cancer Institute has been trying to identify patients with hereditary cancer since 1961. Most physicians at that time believed that cancer was caused by environmental factors, but many started to change their attitude in the mid-1970s. Two hundred inherited cancer syndromes have been identified including two that have been named after Henry Lynch. Individuals from a family with a high incidence of a certain type of cancer should undergo routine screening beginning at an early age.
Publication Name: JAMA, The Journal of the American Medical Association
Subject: Health
ISSN: 0098-7484
Year: 1992
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