Sankila E M, Sistonen P, Cremers F, de la Chapelle A
Department of Medical Genetics, University of Helsinki, Finland.
Hum Genet. 1991 Jul;87(3):348-52. doi: 10.1007/BF00200918.
We report linkage studies in 18 choroideremia (TCD) families using four closely linked polymorphic markers. Probe pZ11, which is known to be deleted in several unrelated patients with TCD, showed no recombinations (zeta max 15.63 at theta = 0.00). In contrast, one recombination was observed with DXS367, which is also physically very close to TCD. Loci DXS95 and DXYS69 each showed more than one recombination with TCD. Moreover, these analyses revealed a double crossover between TCD and DXYS1, changing the previously reported very close linkage to a recombination fraction of 0.04 with a lod score of 9.93. Multipoint linkage analysis placed TCD proximal to DXS95-DXYS69 and very close to DXS367-pZ11 with almost identical multipoint lod score maxima either proximal to DXS367 (zeta max = 23.43) or proximal to pZ11 (zeta max = 23.36). These results provide a refined linkage map around TCD and will also be useful in DNA diagnostics of the disease.
我们使用四个紧密连锁的多态性标记，对18个无脉络膜症（TCD）家族进行了连锁研究。已知在几名无关的TCD患者中缺失的探针pZ11未显示重组（在θ = 0.00时，ζ最大值为15.63）。相比之下，观察到与同样在物理位置上非常接近TCD的DXS367有一次重组。DXS95和DXYS69位点与TCD均显示出不止一次重组。此外，这些分析揭示了TCD与DXYS1之间的双交换，将先前报道的非常紧密的连锁关系改变为重组率为0.04，lod值为9.93。多点连锁分析将TCD定位在DXS95 - DXYS69近端，且非常接近DXS367 - pZ11，在DXS367近端（ζ最大值 = 23.43）或pZ11近端（ζ最大值 = 23.36）具有几乎相同的多点lod值最大值。这些结果提供了围绕TCD的精细连锁图谱，也将有助于该疾病的DNA诊断。
