先天型愚型中G/G易位型占3.3％。我们发现一例21/21易位型先天愚型,现介绍如下: 冯××,男,2(1/2)岁,以反复呼吸道感染及肺炎多次外院治疗。本次患肺炎后口唇紫绀,,呼吸困难遂入我院。患儿系第二胎,第二产,足月顺产,出生体重不详。一岁会坐,现仍不会站立,不会说话。父母非近亲婚配。其母为医药公司仓库保管员,孕期频繁接触多种化学药品;其母智力正常。母系中无痴呆者。其父初中毕业,智力正常;其姐智力正常。父系中两个姑姑智力落后,身 Congenital foolish G / G translocation accounted for 3.3%. We found a case of 21/21 translocation type Down’s syndrome, are described below: Feng × ×, male, 2 (1/2) years old, in order to repeatedly respiratory tract infections and pneumonia multiple external hospital treatment. After suffering from cyanotic lips cyanosis, then into my hospital dyspnea. Children with a second child, the second birth, term full-term birth, birth weight unknown. One year old will sit, still can not stand, can not speak. Parents non-relatives marriage. His mother is a medical company warehouse custodian, frequent contact with multiple chemicals during pregnancy; the mother of normal intelligence. No maternal dementia. His father graduated from junior high school, normal intelligence; sister normal intelligence. Two sons in the father’s intelligence behind, body