Only about one in every four million kids has this disease, and in a simple way, what happens is, because of a mutation in a particular gene, a protein is made that's toxic to the cell and it causes these individuals to age at about seven times the normal rate.
大概四百万分之一的小孩会得这种疾病。 简单说来，其实实际情况就是： 因为某个特定的基因突变， 产生一种对细胞有害的蛋白质， 这对蛋白质造成这些个体衰老。 速度大概是正常衰老速度的七倍。