Keats B J, Pollack M S, McCall A, Wilensky M A, Ward L J, Lu M, Zoghbi H Y
Department of Biometry and Genetics, Louisiana State University Medical Center, New Orleans 70112.
Am J Hum Genet. 1991 Nov;49(5):972-7.
A locus for an autosomal dominant form of spinocerebellar ataxia (SCA1) has been assigned to the short arm of chromosome 6 on the basis of linkage to the major histocompatibility system (HLA). In this study of a five-generation American black family, close linkage between the disease locus and both HLA and the coagulation factor XIIIA (F13A1) locus was excluded, and lod scores for all locations of the disease locus between HLA and F13A1 were less than -1.4. These results suggest that the locus causing spinocerebellar ataxia in this family is not in this region. However, the disease locus was found to be closely linked to a microsatellite polymorphism, D6S89, which is between HLA and F13A1. The maximum lod score for SCA1 and D6S89 is 4.90 at a recombination fraction of 0, both in males and in females. These data show that exclusion of close linkage to the HLA complex and F13A1 in a kindred with spinocerebellar ataxia does not rule out the possibility that the disease locus in that family is on 6p. Accordingly, all families segregating a dominantly inherited ataxia should be evaluated for linkage to D6S89, to determine whether the locus causing the disease is SCA1.
基于与主要组织相容性系统（HLA）的连锁关系，已将常染色体显性遗传性脊髓小脑共济失调（SCA1）的一个基因座定位于6号染色体短臂。在对一个五代美国黑人家庭的这项研究中，排除了疾病基因座与HLA及凝血因子 XIIIA（F13A1）基因座之间的紧密连锁关系，并且疾病基因座在HLA和F13A1之间所有位置的连锁值均小于-1.4。这些结果表明，该家族中导致脊髓小脑共济失调的基因座不在此区域。然而，发现疾病基因座与一个微卫星多态性D6S89紧密连锁，D6S89位于HLA和F13A1之间。男性和女性中，SCA1与D6S89在重组率为0时的最大连锁值均为4.90。这些数据表明，在一个脊髓小脑共济失调家族中排除与HLA复合体和F13A1的紧密连锁关系，并不能排除该家族中疾病基因座位于6p上的可能性。因此，应对所有分离显性遗传性共济失调的家族进行与D6S89连锁关系的评估，以确定导致该疾病的基因座是否为SCA1。
