Yamagata H, Kinoshita M, Komori T, Kondo I, Miki T
Department of Geriatric Medicine, Ehime University School of Medicine, Onsengun, Japan.
Clin Genet. 1998 Oct;54(4):354-7. doi: 10.1034/j.1399-0004.1998.5440416.x.
Here we report two families with myotonic dystrophy (DM) in which the asymptomatic parent proved to be in a pre-mutation state. Polymerase chain reaction (PCR) analysis of the region spanning the CTG expansion demonstrated that one father of the proband possessed (CTG)n repeats of n = 12 and 44 copies and the other of 15 and 47. Clinical examination showed no definite signs of DM in these two men. Haplotype analysis of DNA markers close to the DM protein kinase (DMPK) gene suggested a common ancestral DM mutation. A continuous gradient of repeat sizes from normal to abnormal range can explain this phenomenon.
在此，我们报告了两个患有强直性肌营养不良（DM）的家族，其中无症状的父母被证明处于前突变状态。对跨越CTG扩增区域进行聚合酶链反应（PCR）分析表明，先证者的一位父亲拥有n = 12和44个拷贝的（CTG）n重复序列，另一位父亲拥有15和47个拷贝。临床检查显示这两名男性没有明确的DM体征。对靠近DM蛋白激酶（DMPK）基因的DNA标记进行单倍型分析提示存在一个共同的祖传DM突变。从正常到异常范围的重复序列大小的连续梯度可以解释这一现象。
