目的　检测心脏圆锥干畸形Tbx1基因杂合性缺失情况。方法　以Tbx1基因部分片段为探针 ,用分子细胞遗传学的荧光原位杂交技术检测了 2 2例心脏圆锥干畸形患者 ,其中综合征型 5例 ,孤立型 17例。结果　 5例综合征型患者中有 2例存在2 2q11 2位点上的Tbx1基因的杂合性缺失 ,其余患者中无此现象。另外 ,Northern杂交表明人Tbx1基因在胎心、胎肾以及成人的睾丸、骨骼肌中表达。结论　Tbx1基因可能为上述综合征中某一发育异常的致病基因 ,与心脏圆锥干畸形致病基因的关系有待于无杂合性缺失患者的突变检测 Objective To investigate the loss of heterozygosity of Tbx1 gene in cardiac conical deformity. Methods Twenty-two cases of cardiac concentric deformity were detected by molecular cytogenetics and fluorescence in situ hybridization using partial fragment of Tbx1 gene as a probe. Among them, 5 were syndrome type and 17 were isolated type. Results There were 2 heterozygous deletion of Tbx1 gene at 2 2q11 locus in 2 out of 5 patients with syndrome, and the other patients had no such phenomenon. In addition, Northern blotting indicates that the human Tbx1 gene is expressed in fetal heart, fetal kidney and adult testes, skeletal muscle. Conclusion Tbx1 gene may be a causative gene of some dysplasia in the above syndrome and the relationship with the congenital heart disease congenital malformation gene needs to be detected in patients without loss of heterozygosity