title: Linkage analysis of families with fragile-X mental retardation, using a novel RFLP marker (DXS 304).
abstract: 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.
authors.affiliation: Department of Medical Genetics, University of Uppsala, Sweden.
authors.forename: N
authors.initials: N
authors.lastname: Dahl
authors.forename: P
authors.initials: P
authors.lastname: Goonewardena
authors.forename: H
authors.initials: H
authors.lastname: Malmgren
authors.forename: K H
authors.initials: KH
authors.lastname: Gustavson
authors.forename: G
authors.initials: G
authors.lastname: Holmgren
authors.forename: E
authors.initials: E
authors.lastname: Seemanova
authors.forename: G
authors.initials: G
authors.lastname: Annerén
authors.forename: A
authors.initials: A
authors.lastname: Flood
authors.forename: U
authors.initials: U
authors.lastname: Pettersson
mesh_terms: D002874:Chromosome Mapping; D005260:Female; D005600:Fragile X Syndrome / Q000235:genetics*; D006580:Genetic Carrier Screening; D008040:Genetic Linkage; D005819:Genetic Markers; D006801:Humans; D008297:Male; D010375:Pedigree; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D011995:Recombination, Genetic; D012729:Sex Chromosome Aberrations / Q000235:genetics*; D014960:X Chromosome
chemical_list: D005819:Genetic Markers