title: Close linkage of random DNA fragments from Xq 21.3-22 to X-linked agammaglobulinaemia (XLA).
abstract: Linkage analysis of 15 families affected by X-linked agammaglobulinaemia (XLA) showed close linkage with three probes located towards the centre of the long arm of the X chromosome. No cross-overs were found using pXG12 (DXS94) lod 6.6 or S21 (DXS17) lod 4.4. One cross-over was found with 19.2 (DXS3). This confirms and extends a previous linkage study (Kwan et al. 1986) which demonstrated linkage with S21 and 19.2. Of the families 14 were informative for either pXG12 or S21 and these probes should thus be of great diagnostic value. No evidence of heterogeneity was found in the XLA families but several cross-overs within this region were detected in a family with the X-linked hyper-IgM syndrome confirming this disease as a separate clinical entity.
mesh_terms: D000361:Agammaglobulinemia / Q000235:genetics*; D002874:Chromosome Mapping; D004247:DNA / Q000235:genetics*; D005260:Female; D008040:Genetic Linkage; D005819:Genetic Markers; D006801:Humans; D008297:Male; D010375:Pedigree; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D014960:X Chromosome
chemical_list: D005819:Genetic Markers; D004247:DNA