Clinical application and evaluation of health economics for non-invasive prenatal testing of fetuses in Tianjin / 中华医学遗传学杂志

OBJECTIVE@#To assess the clinical efficacy and health economic value of non-invasive prenatal testing (NIPT) for the prenatal screening of common fetal chromosomal aneuploidies.@*METHODS@#10 612 pregnant women from October 2017 to December 2019 presented at the antenatal screening clinic of the General Hospital of Tianjin Medical University were selected as the study subjects. Results of NIPT and invasive prenatal diagnosis and follow-up outcome for the 10 612 pregnant women were retrospectively analyzed and compared. Meanwhile, NIPT data for two periods were analyzed for assessing the health economic value of NIPT as the second- or first-tier screening strategy for the prenatal diagnosis of fetal trisomies 21, 18 and 13.@*RESULTS@#The NIPT was successful in 10 528 (99.72%) subjects, with the sensitivity for fetal trisomies 21, 18 and 13 being 100%, 92.86% and 100%, and the positive predictive value (PPV) being 89.74%, 61.90% and 44.44%, respectively. The PPV of NIPT for sex chromosome aneuploidies was 34.21%. Except for one false negative case of trisomy 18, the negative predictive value for trisomy 21, trisomy 13 and other chromosomal abnormalities were 100%. For pregnant women with high risk by serological screening, advanced maternal age or abnormal ultrasound soft markers, NIPT has yielded a significantly increased high risk ratio. There was no statistical difference in the PPV of NIPT among pregnant women from each subgroup. NIPT would have higher health economic value as a second-tier screening until 2019, while compared to 2015 ~ 2017, its incremental cost-effectiveness ratio as a first-tier screening had declined clearly.@*CONCLUSION@#The screening efficacy of NIPT for trisomies 21, 18 and 13 for a mixed population is significantly better than conventional serological screening, but it is relatively low for sex chromosomal abnormalities. NIPT can also be recommended for populations with relatively high risks along with detailed pre- and post-test genetic counselling. From the perspective of health economics, except for open neural tube defects, it is possible for NIPT to replace the conventional serological screening in the future as its cost continues to decrease.

Genetic analysis of a fetus with mosaicism Y chromosome aberration / 中华医学遗传学杂志

OBJECTIVE@#To carry out prenatal diagnosis for a fetus with mosaicism Yq deletion.@*METHODS@#A fetus with high risk of sex chromosomes indicated by non-invasive prenatal testing (NIPT) at Tianjin Medical University General Hospital in July 2021 was selected as the study subject. Prenatal diagnosis of the fetus was performed with combined G-banded chromosomal karyotyping, fluorescence in situ hybridization (FISH), copy number variation sequencing (CNV-seq), real-time fluorescence PCR (QF-PCR), and ultrasound examination.@*RESULTS@#Analysis of the amniocytes at 23 gestational weeks had yielded a 45,X karyotype. However, FISH had shown signals of Y chromosome. Re-examination by cordocentesis had shown a mosaicism of 46,X,+mar[33]/45,X[17]. FISH showed that 69% of the cells had contained Y chromosome signals. The result of CNV-seq was seq[19]del(Y)(q11.1q12)(mos) chrY: g.13200001_ 28820000del (mosaicism rate = 64%), which suggested mosaicism for a Yq deletion, which encompassed the azoospermia factor (AZF) region. Deletion of the AZF region was verified by QF-PCR. The fetal karyotype was ultimately determined as mos46,X,del(Y)(q11.1)[33]/45,X[17]. Although ultrasound examination had shown no abnormality in the fetus, the couple had opted to terminate the pregnancy, and the induced fetus had a normal male appearance.@*CONCLUSION@#The combined use of multiple techniques is beneficial for accurate and rapid prenatal diagnosis. For fetuses with mosaicism chromosomal abnormalities, it may be difficult to accurately predict the postnatal phenotype. It is therefore necessary to further explore their genotype-phenotype correlation in order to provide better guidance upon genetic counseling.

Genetic polymorphisms of HPRTB, DXS6803 and DXS6809 STR loci in Tianjin Han female population / 天津医药

Objective To investigate genetic polymorphisms of HPRTB, DXS6803 and DXS6809 STR loci in Tianjin Han female population, and to provide experimental data in the prenatal diagnosis of aneuploidies accurately and rapidly. Methods A total of 150 blood samples were collected in Tianjin Han population. QF-PCR and capillary electrophoresis were used in this study. The relevant data were analyzed by ABI Prism GeneMapper v3.0 software. Two homozygotes were se?lected from each locus for sequencing. The frequencies of the genotypes were checked using Chi-square test to verify Hardy-Weinberg Equilibrium. Data of genetic polymorphisms were calculated by PowerStatsV12 software. Results A total of 150 samples were successfully amplified in 24 hours. The 10, 6 and 10 alleles and 22, 12 and 29 genotypes were found respec?tively in HPRTB, DXS6803 and DXS6809 loci. The most common alleles were 14, 13 and 14. The higher frequencies of gen?otypes were 14-14, 12-13 and 13-14. No significant deviations from the Hardy-Weinberg equilibrium were observed in these three STR loci (χ2=10.554, 5.783 and 15.355, respectively, P>0.05). Values of He were 0.748, 0.649 and 0.806 for these three STR loci respectively. Values of Ho were 0.607, 0.700 and 0.713 respectively. Values of PIC were 0.706, 0.599 and 0.775 respectively. Values of PD were 0.894, 0.814 and 0.931 respectively. And values of PE were 0.299, 0.428 and 0.449 respectively. Conclusion HPRTB, DXS6803 and DXS6809 STR loci were highly polymorphic, which are favorable genetic markers on chromosome X and can be used in rapid prenatal genetic diagnosis.