title: Linkage analysis in the fragile X syndrome using multiple distal Xq polymorphic DNA markers.
abstract: Linkage data using the polymorphic loci F9, DXS105, DXS98, DXS52, DXS15, and F8 and the DNA probe 1A1 are presented from 14 families segregating for fragile X [fra(X)] syndrome. Recombination fractions corresponding to the maximum LOD scores obtained by two-point linkage analysis suggest that DXS98 (Zmax = 3.23, theta = 0.0) and DXS105 (Zmax = 2.09, theta = 0.0) are the closest markers proximal to FRAXA and that DXS52 is the closest distal marker (Zmax = 3.55, theta = 0.16). FRAXA is located within a 25 cM interval between F9 and DXS52, coincident with DXS98, on multipoint linkage analysis. Phase-known three way crossover information places F8 outside the cluster (DXS52, DXS15, 1A1). Confidence limits for the markers DXS98 and DXS52 are relatively wide (0.0-0.15 and 0.06-0.31, respectively), but when used in combination with cytogenetic examination offer improved carrier detection in comparison with cytogenetic analysis alone.
authors.affiliation: University Department of Medical Genetics, Royal Hospital for Sick Children, Yorkhill, Glasgow, Scotland.
authors.forename: I A
authors.initials: IA
authors.lastname: Glass
authors.forename: L A
authors.initials: LA
authors.lastname: Pirrit
authors.forename: E M
authors.initials: EM
authors.lastname: White
authors.forename: M V
authors.initials: MV
authors.lastname: Bell
authors.forename: K E
authors.initials: KE
authors.lastname: Davies
authors.forename: F
authors.initials: F
authors.lastname: Cockburn
authors.forename: J M
authors.initials: JM
authors.lastname: Connor
mesh_terms: D015139:Blotting, Southern; D004247:DNA / Q000032:analysis; D015342:DNA Probes; D005600:Fragile X Syndrome / Q000235:genetics*; D005819:Genetic Markers; D006801:Humans; D008126:Lod Score; D010375:Pedigree; D012150:Polymorphism, Restriction Fragment Length
chemical_list: D015342:DNA Probes; D005819:Genetic Markers; D004247:DNA