Genetic analysis of 387 cases of fetal sex chromosome abnormalities detected from amniotic fluid samples / 中华围产医学杂志

ABSTRACT

Objective:To analyze fetal sex chromosome abnormalities in prenatal diagnosis based on amniotic fluid cell culture.Methods:Clinical data of 12 164 pregnant women who underwent amniocentesis in Maternal and Child Health Hospital of Hunan Province from January 2017 to December 2020 were retrospectively analyzed. For those diagnosed with fetal sex chromosome abnormalities, the results of karyotyping and chromosome microarray analysis (CMA) were analyzed and described.Results:(1) Among the 12 164 cases, fetal sex chromosome abnormalities were detected in 387 cases (3.2%), including 351 cases with abnormal sex chromosome karyotype and 36 with sex chromosome microdeletion/microduplication. (2) High-risk patients indicated by non-invasive prenatal test (NIPT) had the highest proportion of sex chromosomes abnormalities (74.2%, 287/387), followed by those with other ultrasound abnormalities (8.5%, 33/387), high risk of Down syndrome screening (7.0%, 27/387), advanced maternal age (4.7%, 18/387), history of adverse pregnant or delivery (3.3%, 13/387), and nuchal translucency thickening or cervical lymphatic hygroma (2.3%, 9/387). (3) Detected chromosome karyotype abnormalities included numerical abnormalities [73.2%(257/351)], mosaicism [18.8(66/351)], and structural abnormalities [8.0%(28/351)], among which, 47,XXY [46.7%(120/257)], 45,X/46,XX[48.5%(32/66)], and X chromosome deletion [39.3%(11/28)] were the most common, respectively. Among 36 sex chromosome microdeletions/microduplications cases, 15(41.7%) were with pathogenic copy number variation (CNV), including 14 cases of X chromosome microdeletion/microduplication; 7(19.4%) with benign CNV, and 14(38.9%) with CNV of unknown clinical significance. The fragment size [ M (min-max)] of the 15 pathogenic CNV was 1.68 Mb(0.37-9.20 Mb). Of the nine cases with microdeletions, seven were found with deletion in the Xp22.31 region. Conclusions:Numerical abnormalities are the most common fetal sex chromosome abnormalities detected from amniotic fluid samples. Others included mosaicism and chromosome structure abnormalities.