When copying the HTT gene, DNA polymerase can basically lose track of which CAG it's on and accidently add extra CAGs.

当HTT基因复制时，DNA聚合酶基本上无法识别校对CAG序列，意外地导致CAG序列重复。

In most people, a gene called huntingtin or HTT on chromosome 4, contains a triplet repeat, where the nucleotides C, A, and G are repeated 10-35 times in a row.

大多数人体内，位于4号染色体上的HTT基因，有一段三核苷酸重复序列，即核苷酸CAG，连续重复拷贝10-35次。