trisomy syndrome
noun [ U ] medical specialized uk/ˈtrɪ.sə.mi ˌsɪn.drəʊm/ us/ˈtraɪ.soʊ.mi ˌsɪn.droʊm/
三体综合症
a condition in which someone has three rather than two chromosomes in some or all of the body cells
Trisomy 21 syndrome, also called Down's syndrome, affects physical and mental development. 21-三体综合征，又称唐氏综合症，影响身体和精神的发育。