Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0012872 (DNA marker)
 929 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Diagnosis of the carrier status of the fragile X [fra(X)] syndrome was made in 2 unrelated women who did not express the fragile site. Both were related to several individuals with a typical fra(X) phenotype and the marker X chromosome. A restriction fragment length polymorphism (RFLP) approach was used with probes that flank the fra(X) locus (FRAXA). The loci used for risk calculations of the fra(X) genotype were DXS98 and DXS105 on the centromeric side and a recently characterized locus, DXS304, on the telomeric side. Coincidence correction for the distances between marker loci and FRAXA was made according to the Kosambi function. The DNA marker test gave the risk for one female to be a carrier of 99.7-99.9%. In another family a female was excluded from being a carrier with a probability of greater than 99.7%. The DNA marker U6.2, defining the locus DXS304, has increased the reliability of DNA based diagnosis of carrier status for females-at-risk. It is concluded that DNA analysis can serve as a valuable complement to chromosome analysis in families informative for the more closely linked flanking markers.
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PMID:Carrier detection of the fragile X syndrome using flanking loci DXS98, DXS105, and DXS304. 167 4

A new polymorphic DNA marker RN1, defining locus DXS369, was recently isolated. Using different somatic cell hybrids, RN1 was mapped between markers 4D-8 and U6.2. We have narrowed the localization of RN1 to the region between 4D-8 and FRAXA by genetic mapping in fragile X [fra(X)] families. Combined with information from other reports, the following order of loci on Xq27-q28 is suggested: cen-F9-(DXS105-DXS152)-DXS98-DXS369-FRAXA- DXS304-(DXS52-DXS15-F8)-tel. The locus DXS369 is closely linked to FRAXA, with a peak lodscore of 18.5 at a recombination fraction of 0.05. Therefore, RN1 is a useful probe for carrier detection and prenatal diagnosis in fra(X) families.
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PMID:Mapping of a new RFLP marker RN1 (DXS369) close to the fragile site FRAXA on Xq27-q28. 167 6

A new polymorphic DNA marker U6.2, defining the locus DXS304, was recently isolated and mapped to the Xq27 region of the X chromosome. In the previous communication we describe a linkage study encompassing 16 fragile-X families and using U6.2 and five previously described polymorphic markers at Xq26-q28. One recombination event was observed between DXS304 and the fragile-X locus in 36 informative meioses. Combined with information from other reports, our results suggest the following order of the examined loci on Xq: cen-F9-DXS105-DXS98-FRAXA-DXS304-(DXS52-F8 -DXS15). The locus DXS304 is closely linked to FRAXA, giving a peak lod score of 5.86 at a corresponding recombination fraction of .00. On the basis of the present results, it is apparent that U6.2 is a useful probe for carrier and prenatal diagnosis in fragile-X families.
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PMID:Linkage analysis of families with fragile-X mental retardation, using a novel RFLP marker (DXS 304). 256 70

We report the isolation and characterization of a novel DNA marker (1A1) in Xqter in the region of the fragile X. Genetic studies in families segregating for the fragile X syndrome suggest that 1A1 lies between the disease mutation and the distal locus, DXS52. Studies in normal and fragile X families show that 1A1 is tightly linked to DXS52 (Zmax = 17.20; theta max = 0.03) and F8 (Zmax = 7.01; theta max = 0.08). Multipoint mapping of families supports the order Xcen-DXS105-FRAXA-1A1-DXS52-(F8, DXS115)-Xqter. Pulsed-field gel electrophoresis (PFGE) studies demonstrate that 1A1 defines a new region of at least 2 Mb of DNA not physically linked to DXS52 or F8, thus extending the physical map of Xq27-qter to over 4 Mb. Complex partial digestion PFGE patterns, probably due to differing degrees of methylation, are observed with 1A1 in unrelated normal and fragile-X-positive individuals, whereas other distal markers give uniform digestion profiles. Physical data suggest that 1A1 lies in a region less CpG rich than other distal markers in Xq27-qter.
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PMID:Genetic and physical mapping of a novel region close to the fragile X site on the human X chromosome. 274 66