[Distribution of amniotic chromosomal abnormalities and optimization of prenatal diagnosis strategies for pregnant women in Liangshan region].

OBJECTIVE

To investigate the characteristics of chromosomal abnormalities in amniotic fluid among pregnant women in Liangshan Prefecture and explore strategies for optimizing prenatal diagnosis.

METHODS

A retrospective analysis was conducted on 1 024 amniocentesis samples collected at the Prenatal Diagnosis Center of Liangshan Prefecture Maternal and Child Health Care Hospital between February 2022 and December 2024. Chromosome karyotyping analysis (3 cases had failed culture, 1 021 valid samples) was combined with high-throughput chromosome sequencing analysis (CNV-seq) for the detection. This study was approved by the Medical Ethics Committee of the hospital (Ethics No.: 2023-07).

RESULTS

The overall detection rate of chromosomal karyotype abnormalities in the amniotic fluid cells was 4.02% (41/1 021), with numerical abnormalities accounting for 80.49% (33/41) and structural abnormalities for 19.51% (8/41). Numerical abnormalities were primarily trisomy 21 (16/41, 39.02%) and 47,XXY (6/41, 14.63%). Structural abnormalities included translocations (6 cases) and mosaicism (2 cases). CNV-seq detected 22 pathogenic or likely pathogenic copy number variations, whilst the undetection rate for balanced translocations reached 100% (7/7). The combined application of karyotyping and CNV-seq, leveraging complementary strengths, can enhance the overall detection rate.

CONCLUSION

The distribution characteristics of chromosomal abnormalities in amniotic fluid from pregnant women in Liangshan exhibit regional specificity. A combined testing strategy significantly optimizes prenatal diagnosis efficacy, providing crucial evidence for enhancing the effectiveness of prenatal diagnosis in ethnic minority regions.