1例Ⅱ型猫眼综合征的产前诊断

Prenatal diagnosis of a fetus with type Ⅱ cat eye syndrome

目的通过产前诊断确诊1例II型猫眼综合征胎儿,探讨单核苷酸微阵列芯片(SNP-array)技术在标记染色体遗传学诊断中的应用价值。方法无创基因检测(NIPT)孕妇外周血,采用超声仪对胎儿结构进行筛查,并进一步核型分析羊水细胞及其双亲外周血,结合SNP-array检测羊水细胞。结果NIPT提示胎儿22号染色体长臂q11.1q11.21(17.5 Mb-21.5 Mb)位置存在长约4 Mb的微重复。超声发现胎儿复杂型先天性心脏病及胃泡未显示。核型分析胎儿父母染色体未见明显异常,胎儿核型为47,XY,+mar,胎儿SNP-array结果为46,XN,dup(22q11.1-q11.21).[GRCH37/hg19](17.42 Mb-21.46 Mb)×4。结论SNP-array技术对标记染色体可提供更准确的遗传学信息,结合临床表型能够为猫眼综合征诊断以及遗传咨询提供有力依据。

Objective To explore the application of single nucleotide polymorphism array(SNP-array) technique in genetic diagnosis of supernumerary small marker chromosomes(sSMCs) through prenatal diagnosis of a fetus with type Ⅱ cat eye syndrome. Methods Non-invasive prenatal testing(NIPT) was performed on peripheral blood of pregnant woman, ultrasound was used to screen the fetal structure, karyotype analysis was carried out on the amniotic fluid cell of the fetus and peripheral blood of its parents, and amniotic fluid cells were detected by SNP-array. Results NIPT result suggested that 22q11.1q11.21(17.5 Mb-21.5 Mb) had a 4 Mb microduplication. Ultrasound revealed complex congenital heart disease and absent stomach bubble in the fetus. Karyotype analysis showed no obvious abnormalities in his parents, the fetal karyotype was 47,XY,+mar, and the SNP-array result were 46,XN,dup(22q11.1-q11.21).[GRCH37/hg19](17.42 Mb-21.46 Mb)×4. Conclusion SNP-array could provide more accurate genetic information for sSMCs, and provide a strong basis for diagnosis and genetic counseling of cat’s eye syndrome in combination with clinical phenotype.