title: Linkage analysis of multiple endocrine neoplasia type 2A (MEN-2A) and three DNA markers on chromosome 20: evidence against synteny.
abstract: Members of four families in which multiple endocrine neoplasia type 2A (MEN-2A) is segregating were genotyped for three chromosome #20 DNA markers. Close linkage is excluded for the genetic locus of MEN-2A (MEN2A) with each marker locus tested. Using multipoint analysis, the MEN2A locus was excluded from a region 32.5 cM in length encompassing D20S5 and D20S6, two loci that previously had been mapped to the chromosome 20p12.2 region containing the putative deletion associated with MEN-2. In total, we excluded approximately 90.5 cM of chromosome #20 as a possible location of the MEN2A locus. The data from this study do not support increased recombination on the short arms of chromosome #20 and were insufficient to support heterogeneity of MEN-2A as possible explanations for failure to detect linkage between MEN2A and D20S5 or D20S6.
mesh_terms: D002871:Chromosome Banding; D002874:Chromosome Mapping; D002890:Chromosomes, Human, Pair 20; D004247:DNA / Q000235:genetics*; D008040:Genetic Linkage; D005819:Genetic Markers; D006801:Humans; D007621:Karyotyping; D009377:Multiple Endocrine Neoplasia / Q000235:genetics*
chemical_list: D005819:Genetic Markers; D004247:DNA