JAMA : the journal of the American Medical Association
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The selection of individuals for hereditary nonpolyposis colorectal cancer (HNPCC) genetic testing is challenging. Recently, the National Cancer Institute outlined a new set of recommendations, the revised Bethesda guidelines, for the identification of individuals with HNPCC who should be tested for microsatellite instability. ⋯ The revised Bethesda guidelines constitute a useful approach to identify patients at risk for HNPCC. In patients fulfilling these criteria, both microsatellite instability testing and immunostaining are equivalent and highly effective strategies to further select those patients who should be tested for MSH2/MLH1 germline mutations.
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Approximately 60% of families that meet the Amsterdam-I criteria (AC-I) for hereditary nonpolyposis colorectal cancer (HNPCC) have a hereditary abnormality in a DNA mismatch repair (MMR) gene. Cancer incidence in AC-I families with MMR gene mutations is reported to be very high, but cancer incidence for individuals in AC-I families with no evidence of an MMR defect is unknown. ⋯ Families who fulfill AC-I criteria but who have no evidence of a DNA MMR defect do not share the same cancer incidence as families with HNPCC-Lynch syndrome (ie, hereditary MMR deficiency). Relatives in such families have a lower incidence of colorectal cancer than those in families with HNPCC-Lynch syndrome, and incidence may not be increased for other cancers. These families should not be described or counseled as having HNPCC-Lynch syndrome. To facilitate distinguishing these entities, the designation of "familial colorectal cancer type X" is suggested to describe this type of familial aggregation of colorectal cancer.
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Clinicians must be able to diagnose myasthenia gravis, since delays in establishing the diagnosis may put patients at risk for complications from this treatable disease. ⋯ Items in the history and physical examination along with results of certain simple tests performed in the office (ice test, sleep test, and edrophonium test) are useful in predicting the likelihood of myasthenia gravis. These results must be interpreted with caution, however, given the high prevalence of disease in the populations reported in clinical studies. This review is limited by the small number of signs and symptoms scientifically studied and reported in the literature. Future studies evaluating the value of common historical features and easy maneuvers commonly known and practiced by experts in the clinical diagnosis of myasthenia are needed.
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Low birth weight is associated with increased cardiovascular disease in adulthood, and differences in the molecular weight, composition, and quantity of lipoprotein subclasses are associated with coronary artery disease. ⋯ Because apo C-I-enriched HDL, and purified apo C-I alone, promotes apoptosis in vitro, increased amounts of this particle may have physiological significance and identify a novel group of low-birth-weight infants apparently distinct from traditionally classified small-for-gestational-age infants.