Prenatal diagnosis of women with an adverse reproductive history using both traditional karyotyping and SNP-array

Abstract

Objective: To explore the occurrence of fetal chromosomal abnormalities among pregnant women with an adverse reproductive history using traditional karyotyping and single nucleotide polymorphism microarray (SNP-array) technology. Methods: Totally 94 in 2 163 (4.35%) cases of singleton pregnant women with an adverse reproductive history were performed amniocentesis in Jinhua Maternal and Child Health Care Hospital from June 2015 to June 2017. Traditional karyotyping and SNP-array were employed simultaneously for prenatal diagnosis, and the detection rates of the two methods were compared. Results: All of the 94 specimens were successfully analyzed, 11 cases were found with chromosomal anomaly, the overall detection rate was 11.7%(11/94). Seven (7.4%,7/94) abnormalities cases were detected by karyotyping, and 7(7.4%) by SNP-array. The karyotyping results of trisomy 21, and 45,X and the deletion of chromosome 13 were consistent with SNP-array. Only 3 (3.2%, 3/94) microdeletion/duplications (the sizes of duplications and deletions were between 422.4-1 708.4 kb) and 1 (1/4) loss of heterozygosity were detected by SNP-array, but were missed by karyotyping. Furthermore, 2 cases' copy number variation were found pathogenic gene related, while the other 2 were considered benign or variant of uncertain significance. Four cases (4/7) of abnormalities were detected by karyotyping, while confirmed balanced translocation and inversion by SNP-array. All patients were informed and chosen to continue the pregnancy. Conclusions: The rate of abnormal fetal chromosomes in pregnant women with an adverse reproductive history is still high. SNP-array is a new molecular genetic technique, and combined with use of traditional karyotyping, it could improve the detection rate of fetal chromosomal abnormalities and reduce abortion rate, thus providing a basis for genetic counseling and prenatal diagnosis.