Jianrong Li, Yinglong Liu, Xiaodong Lv, Cuntao Yu, Bin Cui, Bo Wei
Cardiovascular Institute and Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
Birth Defects Res A Clin Mol Teratol. 2006 Apr;76(4):262-5. doi: 10.1002/bdra.20246.
Some patients with conotruncal heart defects (CTDs) have a chromosome 22q11.2 deletion, but we do not know whether patients with CTDs who are missing the peripheral blood-cell chromosome 22q11.2 deletion are also missing the 22q11.2 deletion in myocardial cells, and whether patients with the 22q11.2 deletion can show a different 22q11.2 deletion in peripheral blood cells and myocardial cells due to a postzygotic mutation during the embryonic period.
A total of 32 Chinese pediatric nonsyndromic CTD patients (21 with tetralogy of fallot [TOF], 9 with double outlet right ventricle [DORV], 1 with pulmonary artery atresia with ventricular septal defect [PAA/VSD], and 1 with congenitally corrected transposition of the great arteries [CCTGA]), 12 females and 20 males ranging in age from 5 months to 7 years, were included in our study. We used fluorescence in situ hybridization (FISH) to find the chromosome 22q11.2 deletion in peripheral blood cells and compared genotypes of 15 short tandem repeat (STR) markers within 22q11.2 between peripheral blood cells and myocardial cells to search for genetic mosaicism of the chromosome 22q11.2 deletion.
Three patients, 2 with TOF and 1 with DORV, were determined to have the peripheral blood cell chromosome 22q11.2 deletion. There was no STR genotypic difference observed between peripheral blood cells and myocardial cells in patients with or without the chromosome 22q11.2 deletion.
Genetic mosaicism may not play a major role in the etiology of isolated CTDs.
部分圆锥动脉干心脏缺陷（CTD）患者存在22号染色体q11.2缺失，但我们尚不清楚外周血细胞不存在22号染色体q11.2缺失的CTD患者，其心肌细胞中是否也不存在该缺失，以及22号染色体q11.2缺失的患者是否会因胚胎期的合子后突变，在外周血细胞和心肌细胞中表现出不同的22号染色体q11.2缺失。
本研究纳入了32例中国儿童非综合征性CTD患者（21例法洛四联症[TOF]、9例右心室双出口[DORV]、1例室间隔缺损合并肺动脉闭锁[PAA/VSD]、1例先天性矫正型大动脉转位[CCTGA]），年龄5个月至7岁，其中女性12例，男性20例。我们采用荧光原位杂交（FISH）检测外周血细胞中的22号染色体q11.2缺失，并比较外周血细胞和心肌细胞中22q11.2区域内15个短串联重复序列（STR）标记的基因型，以寻找22号染色体q11.2缺失的遗传嵌合现象。
3例患者被确定存在外周血细胞22号染色体q11.2缺失，其中2例TOF患者，1例DORV患者。无论有无22号染色体q11.2缺失，患者外周血细胞和心肌细胞之间均未观察到STR基因型差异。
遗传嵌合现象可能在孤立性CTD的病因中不起主要作用。
