Hu L J, Blumenfeld-Heyberger S, Hanauer A, Weissenbach J, Mandel J L
Laboratoire de Génétique Moléculaire des Eucaryotes du CNRS, Unité 184 de Génétique Moléculaire de l'INSERM, Faculté de Médecine, Strasbourg, France.
Am J Med Genet. 1994 Jul 15;51(4):569-74. doi: 10.1002/ajmg.1320510455.
We have previously reported linkage analysis in 3 families with non-specific X-linked mental retardation (XLMR). This used RFLPs and was limited by the relatively low informativeness and density of markers available. We have performed a new linkage analysis using microsatellites (including new Genethon markers) in the two most informative families. In the MRX2 family, a lod score of 2.61 at theta = 0.05 had previously been obtained with DXS85 in Xp22.2. We now report a tighter linkage with AFM 135xe7 (DXS989, z = 4.62 at theta = 0.00) and established the order DXS85-DXS207-DXS999 (AFM234 y12)-MRX2, DXS365, DXS1052 (AFM 163yh2), DXS989-DXS1065 (AFM224zf2), DMD 3'. The localization of MRX2 in Xp22.2-p22.1 is thus clearly different from the more distal MRX gene defined by patients with contiguous gene syndromes. In the MRX4 family, a maximum lod score of 2.53 at theta = 0.00 had been obtained with DXS159 in Xq13. Our present study did not show recombination from ALAS2 in Xp11.21 to DXS441 in Xq13.3 (z = 3.38 at theta = 0.00 for the latter marker) and the closest flanking markers are DXS255 in Xp11.22 and DXYS1 in Xq21.3. Reduced recombination around the centromere prevents precise mapping. The localisation of MRX4 overlaps with that of several other MRX families.
我们之前报道过对3个患有非特异性X连锁智力迟钝（XLMR）家族的连锁分析。该分析使用了限制性片段长度多态性（RFLP），但受到可用标记相对较低的信息含量和密度的限制。我们在两个信息含量最高的家族中使用微卫星（包括新的Genethon标记）进行了新的连锁分析。在MRX2家族中，之前使用位于Xp22.2的DXS85在θ = 0.05时获得了2.61的连锁对数。我们现在报告与AFM 135xe7（DXS989，在θ = 0.00时z = 4.62）有更紧密的连锁，并确定了顺序为DXS85 - DXS207 - DXS999（AFM234 y12） - MRX2，DXS365，DXS1052（AFM 163yh2），DXS989 - DXS1065（AFM224zf2），DMD 3'。因此，MRX2在Xp22.2 - p22.1的定位明显不同于由连续性基因综合征患者定义的更靠远端的MRX基因。在MRX4家族中，使用位于Xq13的DXS159在θ = 0.00时获得了2.53的最大连锁对数。我们目前的研究未显示从Xp11.21的ALAS2到Xq13.3的DXS441之间发生重组（对于后一个标记，在θ = 0.00时z = 3.38），最紧密的侧翼标记是Xp11.22的DXS255和Xq21.3的DXYS1。着丝粒周围重组减少妨碍了精确作图。MRX4的定位与其他几个MRX家族的定位重叠。
