一例t（1；2），t（6；7）非平衡易位伴智力障碍孕妇的遗传学分析与产前诊断

Genetic analysis and prenatal diagnosis for a pregnant woman with an unbalanced t（1;2）,t（6;7） translocation and intellectual disability

目的对1例染色体易位伴智力障碍的孕妇进行遗传学分析，并为其胎儿提供产前诊断。方法采用常规G显带法分析孕妇及胎儿的染色体核型，并应用微阵列比较基因组杂交技术 （ arraycomparative genomic hybridization, array-CGH） 对孕妇及胎儿进行染色体拷贝数分析。结果孕妇的染色体核型为46，XX，t（1；2）（p22；p23），t（6；7）（q21；p15），胎儿羊水细胞的染色体核型为46，XY，t（6；7）（q21；p15）mat。array-CGH检测显示孕妇及胎儿均携带arr[hg19]6q22．1q22．31（115311507—119332956）片段缺失，长度约4Mb。考虑到染色体6q22．1-q22．31微缺失可能与孕妇的临床表型相关，孕妇家属决定终止妊娠。引产胎儿为男性，外观未见明显异常。结论对于染色体易位伴智力障碍孕妇的产前诊断是一项充满挑战的工作，染色体核型分析和array-CGH的联合应用将有助于明确诊断和遗传咨询。

Objective To provide genetic analysis for a pregnant woman with chromosomal translocations and intellectual disability, and to provide prenatal diagnosis for her fetus. Methods Routine G-banding was performed to analyze the karyotypes of the woman and her fetus. Copy number variants were determined with array comparative genomic hybridization （array-CGH）. Results The pregnant woman has carried an apparently balanced translocation involving chromosomes 1, 2, 6 and 7, with a karyotype of 46, XX, t （ 1 ; 2） （ p22 ; p23 ）, t （ 6 ; 7 ） （ q21 ; p15 ）. The karyotype of her fetus was ascertained as 46, XY, t （ 6 ; 7 ） （q21;p15）mat. Array-CGH has detected a 4 Mb mierodeletion at 6q22.1-q22.31 （115 311 507-119 332 956） in both individuals. As the 6q22. 1-q22. 31 microdeletion may be associated with the main clinical manifestations of the woman, the family decided to terminate the pregnancy. The fetus was male and appeared to have no obvious abnormality. Conclusion Prenatal diagnosis for pregnant women with translocations and mental retardation is a challenging task. Combined application of cytogenetic analysis and array-CGH may facilitate the diagnosis and genetic counseling.