多重连接探针扩增技术在先天性心脏病22q11微缺失/微重复综合征诊断中的应用

Diagnosis of 22q11 deletion and duplication in congenital heart disease by multiplex ligation-dependent probe amplification

摘要:

目的:染色体22q11区域基因拷贝数异常是先天性心脏病（CHD）的遗传病因之一，由其引起的CHD预后不良。该研究主要探讨多重连接探针扩增技术用于CHD 22q11微缺失或微重复遗传病因诊断的实用性，并了解22q11微缺失或微重复在CHD中的发生情况。方法:选择25个位于染色体22q11低重复拷贝序列A-H区域内、7个位于其周围（CES、22q13）和16个位于4、8、10、17号染色体上的基因位点共计48个探针组成多重连接探针，对181例外科手术前的CHD儿童和14例严重CHD或包括CHD的多发性畸形胎儿进行了22q11微缺失或微重复的检测，并进行了染色体核型分析。结果:195例患儿中，共检出22q11微缺失者7例（LCR A-D区6例，LCR A-C区1例），22q11微重复1例（LCR B-D区），涉及的CHD类型包括室间隔缺损、房室间隔缺损、肺动脉狭窄和法洛四联征。同时染色体核型分析还发现了6例异常：1例21q部分缺失［46，XY，21q-］，1例嵌合性8-三体［47，XY，+8/46，XY（1∶2）］，4例21-三体。其中1例21-三体与22q11微重复同时存在。结论:染色体22q11区域高密度多重连接探针检测技术能快速、灵敏、精确定位诊断染色体22q11区域基因拷贝数异常，适合于CHD的遗传学诊断；此外，22q11微缺失或微重复引起的CHD类型多种多样，建议所有CHD患者应常规进行遗传学检测。［中国当代儿科杂志，2009，11（11）：892-896］

Abstract:

OBJECTIVE: To investigate the clinical utility of multiplex ligation-dependent probe amplification (MLPA) for detecting 22q11 deletion and duplication in congenital heart disease (CHD) cases and to study the incidence of 22q11 deletion and duplicaton in different kinds of CHD. METHODS: Forty-eight probes of which 25 located in 22q11 low copy number region (LCR 22s A-H), 7 in 22q11 surrounding region (CES, 22q13) and 16 in chromosomes 4, 8, 10 and 17 were selected to detect 22q11 deletion and duplication in 181 preoperative children with CHD and 14 fetuses with serious CHD or CHD with multiple malformations. In these cases, karyotype analysis was also performed. RESULTS: MLPA demonstrated that 7 cases had 22q11 deletion ［6 cases from CLTCL1 to LZTR1(LCR A-D) and 1 case from CLTCL1 to PCQAP (LCR A-C)］ and that 1 case had 22q11 duplication，spanning from ZNF74 to LZTR1(LCR B-D). The phenotypes of heart defect included ventricular septal defect, atrioventricular septal defect, pulmonary stenosis and tetralogy of Fallot. Karyotype analysis showed that 1 case had 21q deletion ［46, XY, 21q］, 1 case had mosaic trisomy 8 ［ 47,XY,+8/46, XY(1∶2)］ and 4 cases had trisomy 21. One of the 4 cases with trisomy 21 had concurrent 22q11 duplication. CONCLUSIONS: MLPA is a rapid, sensitive, site-specific and relatively inexpensive method for diagnosis of 22q11 deletion and duplication in CHD. 22q11 deletion and duplication may cause various kinds of CHD, suggesting that genetic detection should be performed routinely in CHD patients.［Chin J Contemp Pediatr, 2009, 11 (11):892-896］