Zhu Danqing, Burke Christopher, Leslie Anthony, Nicholson Garth A
Neurobiology Department, ANZAC Research Institute, University of Sydney, Concord Hospital, Concord, NSW, Australia.
Mov Disord. 2002 May;17(3):585-9. doi: 10.1002/mds.10175.
Friedreich's ataxia (FRDA) is the most common hereditary ataxia, affecting about 1 in 50,000 individuals. It is caused by mutations in the frataxin gene; 98% of cases have homozygous expansions of a GAA trinucleotide in intron 1 of the frataxin gene. The remaining 2% of patients are compound heterozygotes, who have a GAA repeat expansion in one allele and a point mutation in the other allele. FRDA patients with point mutation have been suggested to have atypical clinical features. We present a case of compound heterozygotes in a FRDA patient who has a deletion of one T in the start codon (ATG) of the frataxin gene and a GAA repeat expansion in the other allele. The patient presented with chorea and subsequently developed FRDA symptoms. The disease in this case is the result of both a failure of initiation of translation and the effect of the expansion. This novel mutation extends the range of point mutations seen in FRDA patients, and also broadens the spectrum of FRDA genotype associated with chorea.
弗里德赖希共济失调（FRDA）是最常见的遗传性共济失调，每5万人中约有1人受其影响。它由铁调素基因的突变引起；98%的病例在铁调素基因第1内含子中有GAA三核苷酸的纯合扩增。其余2%的患者为复合杂合子，他们在一个等位基因中有GAA重复扩增，而在另一个等位基因中有一个点突变。有研究表明，携带点突变的FRDA患者具有非典型临床特征。我们报告了一例FRDA复合杂合子患者，该患者铁调素基因起始密码子（ATG）缺失一个T，另一个等位基因中有GAA重复扩增。该患者最初表现为舞蹈症，随后出现FRDA症状。此病例中的疾病是翻译起始失败和扩增效应共同作用的结果。这种新突变扩展了FRDA患者中所见点突变的范围，也拓宽了与舞蹈症相关的FRDA基因型谱。
