Prenatal diagnosis and counseling of fetal chromosomes with structural abnormalities

Abstract

Objectives To explore the pregnancy, fertility risk and genetic suggestions of pregnant women with complex structural abnormalities of fetal chromosomes. Study Design Amniotic fluid puncture, chromosome culture of amniotic fluid and chromosome G banding analysis were performed on 9867 pregnant women who came to our hospital for prenatal diagnosis from 2012 to 2023, CMA was performed in 8 pregnant women with complex structural abnormalities in amniotic fluid. Results Chromosome G banding analysis showed that the karyotypes of all 8 cases were structural abnormalities, with deletion and duplication, combined with CMA results, comprehensive analysis showed that case 1 was derived chromosome 3 with deletionof 3p13p14. In case 2, 7q11.23q21.3 was inserted at 4q31.3. Case 3 was derived chromosom 16 with deletion of 16p13.3 and duplication of 18q12.3q23. Case 4 was derived chromosome 9 with duplication of 20p12.1p13. Case 5 was derived chromosome 21 with duplication of 2p22.2p25.3 and 21q11.2q21.3. Case 6 was derived chromosome21 with duplication of 18q12.3q23; Case 7 was derived chromosome 4 with duplication of 4q26q35.2(116376542_188138856) and deletion of 4q35.2(188155531_190957460), and case 8 was derived chromosome X with duplication of Xp22.31p11.1(9041083_58455353) and deletion of Xp22.33p22.31(168552_9040480). Conclusion The combination of G-banding analysis technology and CMA can not only detect the complex structural abnormalities of the amniotic fluid chromosomes, but also determine whether the missing or repeated regions contain important genetic genes. Then, by referring to the results of the parents' chromosomes or the results of ultrasound examination, the abnormalities of fetal chromosomes are summarized and analyzed, so as to obtain clinical consultation opinions.