OBJECTIVE: To analyze the results of prenatal diagnosis for fetuses with a high risk for sex chromosome aneuploidies (SCAs) indicated by non-invasive prenatal testing (NIPT), and to assess the influence of maternal chromosomal factors on the results of NIPT. METHODS: A retrospective analysis was conducted on the clinical data of 454 pregnant women with a high risk for SCAs indicated by NIPT undergoing invasive prenatal diagnosis at the Medical Genetics Center of Northwest Women's and Children's Hospital from January 2022 to September 2024. The data has included prenatal diagnosis indications, results, pregnancy outcomes, and the chromosomal results of pregnant women. RESULTS: Among the 454 women (including 10 with twin pregnancy) with a high risk for SCAs indicated by NIPT, 149 (including 4 twin cases) were diagnosed with SCAs through invasive prenatal diagnosis. These had included 47,XXX (37 cases), 47,XXY (56 cases), 47,XYY (29 cases), 45,X (1 case), 48,XXYY (1 case), mosaicism (20 cases), sex chromosome structural abnormalities (6 cases), and small-scale pathogenic copy number variations (3 cases). 383 pregnant women (including 7 with twin pregnancy) had accepted chromosomal karyotyping analysis. In total 49 cases of SCAs abnormalities were detected. Among them, 41 cases were pregnant women with SCAs but normal fetal chromosomes, which yielded a false positive rate for NIPT caused by maternal factors by 10.7%. In addition, 8 cases (including 1 twin case) had SCAs abnormalities in both the pregnant woman and the fetus. Among the 383 pregnant women, 129 cases (including 3 twin cases) of fetal SCAs were diagnosed, which yielded an overall positive predictive value (PPV) of NIPT for SCAs by 33.7% (129/383). With the 41 false positive cases caused by maternal SCAs abnormalities excluded, the PPV of NIPT for SCAs will be increased to 37.7% (129/342). Among the 454 pregnant women, twin pregnancies have accounted for 2.2% (10/454). Among the confirmed cases of SCAs abnormalities, twin cases accounted for 2.7% (4/149). Among the 383 pregnant women undergoing chromosomal karyotyping, twin cases accounted for 1.8% (7/383). Among the detected cases of chromosomal abnormalities, twin cases accounted for 2.0% (1/49). By calculation, the proportion of singleton pregnant women with a high risk for SCAs indicated by NIPT was approximately 32.1%, and the proportion of twin pregnant women was approximately 38.6%, indicating that twin pregnancies could increase the positive rate of NIPT. CONCLUSION NIPT can improve the screening efficiency for SCAs, but its PPV is limited. Therefore, pregnant women with a high risk for SCAs indicated by NIPT need to undergo invasive prenatal diagnosis for a definite diagnosis, and twin pregnancies can increase the positive rate of NIPT. The study confirmed that chromosomal abnormalities in pregnant women can significantly affect the accuracy of NIPT in detecting fetal SCAs. Therefore, when NIPT indicates SCAs abnormalities, it is recommended to simultaneously conduct chromosomal testing on the pregnant women. The combined application of chromosomal karyotyping analysis, fluorescence in situ hybridization, and copy number variation detection techniques can significantly improve the diagnostic accuracy for SCAs, especially for the detection of mosaicisms.
Humans ; Female ; Pregnancy ; Sex Chromosome Aberrations ; Adult ; Retrospective Studies ; False Positive Reactions ; Prenatal Diagnosis/methods* ; Noninvasive Prenatal Testing/methods* ; Aneuploidy ; Male ; Sex Chromosome Disorders/genetics*

OBJECTIVE: To explore a case of abnormal fetal development due to a rare paternal t(10;14)(p11.2;p11) translocation. METHODS: A fetus undergoing prenatal diagnosis at Northwest Women's and Children's Hospital on June 21,2024 was selected as the study subject. Clinical data were collected. Amniotic fluid sample of the fetus and peripheral venous blood samples of its parents were collected for chromosomal karyotyping and copy number variation (CNV) analysis. This study was approved by the Ethics Committee of the hospital (Ethics No.: 2024-132). RESULTS: Ultrasound scan at 23⁺⁴ gestational weeks revealed nasal bone dysplasia. Amniotic fluid analysis revealed that the fetus has a karyotype of 46,X?,der(14)t(10;14)(p11.2;p11)dpat, while its father had a 46,XY,t(10;14)(p11.2;p11) karyotype. No chromosomal abnormality was found in its mother. CNV analysis revealed that the fetus had a 30.46 Mb duplication in the 10p15.3-p11.23 region. Based on the guidelines from the American College of Medical Genetics and Genomics (ACMG), the duplication was classified as pathogenic. CONCLUSION By combining conventional cytogenetic methods with molecular techniques, the fetus was diagnosed with partial trisomy 10p syndrome caused by a rare paternal t(10;14)(p11.2;p11) translocation. Above finding holds significant clinical value for genetic counseling and prenatal diagnosis for the family.
Humans ; Translocation, Genetic ; Female ; Pregnancy ; Male ; Phenotype ; Chromosomes, Human, Pair 10/genetics* ; Adult ; Chromosomes, Human, Pair 14/genetics* ; Prenatal Diagnosis ; Karyotyping ; DNA Copy Number Variations/genetics* ; Fetus/abnormalities*