巨颅伴皮层下海绵样囊肿性脑白质病的病变基因定位于染色体22q13.3上250kb区域内

目的 :巨颅伴皮层下海绵样囊肿性脑白质病 (MLC)是近来被证实的一种新的常染色体隐性遗传病 ,该病的可能病变基因被确定在染色体 2 2qtel上的 3 cM区域内 ,通过研究将病变基因的可能范围进一步缩小。方法 :收集 3 3个家庭中的 3 9例MLC病人 ,对其中能提供丰富遗传信息的 1 2例家庭成员 ,运用 7个微卫星标识和 4个单核苷酸多态性标识进行连锁分析和单倍体型分析。结果 :在重组值为 0 0 2下微卫星标识 3 55c1 8的最大两点LOD值是6 65;采用单倍体型分析进一步将位于 2 2qtel上的MLC病变基因的关键位置缩小在 2 50kb内。结论 :MLC病变基因位于 2 2qtel上 2 50kb内 ,有 4个候选基因被考虑。另外 ,由于其中一个家庭成员存在遗传异质性 ,故考虑MLC可能存在第二个病变基因位点。

The Gene of Megalencephalic Leukoencephalopathy with Subcortical Cysts is Mapped on Chromosome 2 2q 13.3 with 2 5 0 kb Interval

Objective: Vacuolating megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a recently described syndrome with autosomal recessive mode of inheritance. Its possible gene was located on chromosomal 22q tel with 3-cM. The purpose of this study was to narrow down the genetical distance on chromosomal 22q tel with MLC. Methods: Thirty-nine MLC patients in 33 families were collected,and the linkage analysis and haplotype analysis of twelve informative families were done, using seven microsatellite markers and four SNP markers. Results: The maximum tow-point LOD score for marker 355c18 was 6.65 at recombination fraction 0.02. The haplotype analysis narrowed down the critical region of MLC to 250 kb on chromosomal 22q tel. Conclusion: One of the causing genes of MLC was located on chromosomal 22q tel with 250 kb. Four candidate genes were considered. The heterogeneity of one informative family indicated possible existence of a second locus for MLC.