Yamagishi H, Ishii C, Maeda J, Kojima Y, Matsuoka R, Kimura M, Takao A, Momma K, Matsuo N
Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan.
Am J Med Genet. 1998 Jul 24;78(4):319-21.
We report on male monozygotic twins with 22q11.2 deletion and discordant phenotypes. The twins had twin-to-twin transfusion syndrome. Twin 1, the smaller of the pair, had Tetralogy of Fallot, a characteristic facial appearance, swallowing dysfunction, anal atresia, short stature, and mental retardation, whereas twin 2 had a characteristic facial appearance but no other signs of the 22q11 deletion syndrome. Fluorescence in situ hybridization analysis showed a microdeletion on chromosome 22q11.2 in both twins. Zygosity analysis gave a probability of monozygosity greater than 99.999%. These observations indicate that environmental factors or postzygotic events play a role in the phenotypic variability in the twins.
我们报告了一对患有22q11.2缺失且表型不一致的男性同卵双胞胎。这对双胞胎患有双胎输血综合征。双胞胎1是较小的那个，患有法洛四联症、典型的面部外观、吞咽功能障碍、肛门闭锁、身材矮小和智力发育迟缓，而双胞胎2有典型的面部外观，但没有22q11缺失综合征的其他体征。荧光原位杂交分析显示，两个双胞胎的22号染色体q11.2区域均存在微缺失。合子性分析得出同卵性概率大于99.999%。这些观察结果表明，环境因素或合子后事件在双胞胎的表型变异中起作用。
