什么是唐氏综合征　唐氏综合征是以JohnLangdonDown命名的 ,于 1 86 6年第一次被描述 ,这是一种存在额外的 2 1号染色体遗传改变 ,唐氏综合征共有 3种主要类型 :即完型 2 1三体 ;嵌合体型 2 1三体 ;易位型 2 1三体。病症　双眼上斜 ;双眼内呲之间 ,皮肤有垂直方向上折叠 (内呲 What is Down Syndrome Down Syndrome is named after John Langdon Down and was first described in 1886 as an additional genetic change in chromosome 2 1 with three major types of Down Syndrome : Complete type 2 1 trisomy; chimera type 2 1 trisomy; translocation type 2 1 trisomy. Illness eyes oblique; eyes bared between the skin fold in the vertical direction (within the bared