目的 对1个连续两次发生胎儿1p31.1区拷贝数异常(微缺失和微重复各一次)的家系进行检测和分析,明确其原因,探讨单核苷酸多态性微阵列芯片(single nucleotide polymorphism array,SNParray)联合G显带染色体核型分析在临床遗传学诊断中的应用价值.方法 对同一孕妇的两次妊娠分别进行羊膜腔穿刺和绒毛膜穿刺.采用SNP array对胎儿进行全基因组扫描,对胎儿的双亲进行外周血染色体G显带联合SNP-array分析.结果 孕妇第1次妊娠胎儿SNP-array结果为1p31.1(70 164 686~83 474 843)×1;第2次妊娠胎儿SNP-array结果为1p31.1(70 164 686~83 479 747)×3.胎儿双亲外周血SNP array结果正常,但胎儿母亲染色体G显带结果为46,XX,inv(1)(p31.1p32.1).结论 胎儿母亲1号染色体臂内倒位可能是导致胎儿1p31.1区拷贝数连续两次异常的原因.SNP-array联合染色体G显带分析适用于同一染色体区带微缺失微重复的产前诊断,为遗传咨询提供依据.
Objective To analyze a family with recurrent fetal copy number variations (microdeletion and microduplication,respectively) of 1p31.1 using single nucleotide polymorphisrn based array (SNP array) and G banding chromosomal karyotyping.Methods Amniocentesis and chorionic villus sampling were performed for a woman during the two pregnancies.Whole genome SNP array was used to detect genomic imbalance of the fetus.The couple was also subjected to G-banding chromosomal analysis and SNP-array analysis.Results SNP array showed a 1p31.1 (70 164 686 83 474 843) × 1 and a 1p31.1 (70 164 686-83 479 747) × 3 in the fetuses during the two pregnancies,respectively.SNP array results of the couple appeared to be normal.The mother of the fetuses had a 46,XX,inv(1)(p31.1p32.1) karyotype.Conclusion The paracentric inversion in chromosome 1 in the gravida probably underlies the recurrent 1p31.1 copy number variations in the fetuses.SNP-array combined with G banding chromosomal analysis are suitable for prenatal diagnosis for recurrent microdeletion and microduplication in the same chromosomal region,and can provide detailed information for genetic counseiing.