Nørby S, Schwartz M
Clin Genet. 1987 Mar;31(3):192-7. doi: 10.1111/j.1399-0004.1987.tb02794.x.
During diagnostic segregation analysis for seven DNA markers, linked to and flanking the locus for Duchenne muscular dystrophy (DMD), a family was identified in which a boy with a recombinant X chromosome had inherited his maternal grandmother's alleles at the loci DXS43 (D2/Pvu II) and DXS28 (C7/Eco RV), and his maternal grandfather's alleles at DXS67 (B24/Msp I) and DXS84 (754/Pst I). Combined with earlier data this finding strongly suggests the locus order DXS28-DXS67-DMD. Another recombination event, identified in the same family, supports the previously established order DMD-DXS84-OTC. The diagnostic importance of flanking markers, and the likelihood of false diagnostic conclusions due to possible double crossovers, with and without demonstrable neighbouring single crossover events, are discussed.
在对与杜兴氏肌营养不良症（DMD）基因座相连并位于其两侧的七个DNA标记进行诊断性分离分析时，发现了一个家系，其中一名具有重组X染色体的男孩在DXS43（D2/Pvu II）和DXS28（C7/Eco RV）基因座上继承了其外祖母的等位基因，在DXS67（B24/Msp I）和DXS84（754/Pst I）基因座上继承了其外祖父的等位基因。结合早期数据，这一发现强烈提示基因座顺序为DXS28 - DXS67 - DMD。在同一家系中发现的另一个重组事件支持了先前确定的顺序DMD - DXS84 - OTC。讨论了侧翼标记的诊断重要性，以及由于可能的双交换（无论有无可证实的相邻单交换事件）导致错误诊断结论的可能性。
