Differential stability of the (GAA)(n) tract in the Friedreich ataxia (STM7) gene
Differential stability of the (GAA)(n) tract in the Friedreich ataxia (STM7) gene
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DOI：
10.1007/s004390050458
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发表时间：
1997-06-01
期刊：
影响因子：
5.3
通讯作者：
Schols, L
中科院分区：
文献类型：
--
作者：
Epplen, C;Epplen, JT;Schols, L
弗里德里希共济失调（FA）是一种常染色体隐性遗传病。以多嘌呤三核苷酸扩增为特征的神经退行性疾病。（GAA）(n)基序位于染色体9q13上STM7基因的18号内含子（以前认为是X25基因的1号内含子）上。我们研究了178名健康个体的多态（GAA）(n)重复束的分布概况。三核苷酸片段的重复次数从7到29不等。在三个个体中，GAA基序的重复次数超过29次。其中两个人将被诊断为FA突变（GAA大小为bbbb90）的携带者，而第三个人的状态是GAA（58）。目前看来不太清楚。因此，可以假设德国人口的FA携带率为1/60至1/90。此外，一个中等大小的等位基因（GAA）（38）被发现在一个母亲的两个患病的孩子。（GAA）（38）等位基因在传播过程中至少扩展到（GAA）（66）和（GAA）（bbb400）。因此，已知最短的STM7等位基因是（GAA）（66）。这些新的事实必须考虑鉴别诊断和FA携带者状态的定义。
Friedreich ataxia (FA) is an autosomal recessive. neurodegenerative disorder characterized by polypurine trinucleotide expansion. The (GAA)(n) motif is located in intron 18 of the STM7 gene (previously considered as intron 1 of the X25 gene) on chromosome 9q13. We studied the distribution profile of the polymorphic (GAA)(n) repetitive tract in 178 healthy individuals. The number of repeats of the trinucleotide block ranged from 7 to 29. In three individuals there were more than 29 repetitions of the GAA motif. While two of the individuals would be diagnosed as carriers of the FA mutation (GAA size > 90), the status of the third person, with a (GAA)(58) tract. appears less clear at present. Thus an FA carrier rate of 1/60 to 1/90 can be assumed for the German population. In addition an intermediate-sized allele, (GAA)(38) was identified in a mother with two affected children. The (GAA)(38) allele appears to be expanded during transmission to at least (GAA)(66) and (GAA)(> 400) in her two FA-affected offspring. Therefore the shortest known STM7 allele conferring FA is (GAA)(66). These novel facts have to be considered for differential diagnosis and definition of the FA carrier state.