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Visualization using NIPTviewer support the clinical interpretation of noninvasive prenatal testing results.

BACKGROUND: Noninvasive prenatal testing (NIPT) is increasingly used to screen for fetal chromosomal aneuploidy by analyzing cell-free DNA (cfDNA) in peripheral maternal blood. The method provides an opportunity for early detection of large genetic abnormalities without an increased risk of miscarriage due to invasive procedures. Commercial applications for use at clinical laboratories often take advantage of DNA sequencing technologies and include the bioinformatic workup of the sequence data. The interpretation of the test results and the clinical report writing, however, remains the responsibility of the diagnostic laboratory. In order to facilitate this step, we developed NIPTviewer, a web-based application to visualize and guide the interpretation of NIPT data results. RESULTS: NIPTviewer has a database functionality to store the NIPT results and a web interface for user interaction and visualization. The application has been implemented as part of a novel analysis pipeline for NIPT in a diagnostic laboratory at Uppsala University Hospital. The validation data set included 84 previously analyzed plasma samples with known results regarding chromosomes 13, 18, 21, X and Y. They were sequenced in six different experiments, uploaded to NIPTviewer and assigned to a clinical laboratory geneticist for interpretation. The results of all previously analyzed samples were replicated. CONCLUSION: NIPTviewer facilitates NIPT results interpretation and has been implemented as part of a NIPT analysis routine that was accredited by the national accreditation body for Sweden (Swedac).

Humans

Different options for prenatal testing for Huntington's disease using DNA probes.

The discovery of DNA markers closely linked to the gene for Huntington's disease (HD) has allowed development of predictive and prenatal testing programmes for HD. This report describes four different approaches to prenatal testing for HD which have arisen during a pilot predictive and prenatal testing program in British Columbia, Canada. In the first approach (exclusion testing), the at risk parent cannot or prefers not to learn of his/her HD status. Two other approaches involve definitive testing of a fetus when a parent is determined to be at increased risk to have inherited the HD gene or is affected with Huntington's disease. The fourth approach is a stepwise combination of the above two methods which we refer to as 'exclusion-definitive' testing. These different approaches introduce a variety of challenging counselling and ethical issues. The role of each approach to prenatal testing in the management of Huntington's disease awaits the results of this and other predictive and prenatal testing programmes.

Adult

Analysis of prenatal diagnosis and pregnancy outcomes for rare autosomal trisomies detected by non-invasive prenatal testing in 33,079 cases.

BACKGROUND: Non-invasive prenatal testing is widely used for screening common fetal aneuploidy disorders such as trisomy 21, trisomy 18, and trisomy 13. However, its ability to detect rare autosomal trisomies has introduced a new layer of complexity and clinical uncertainty. METHODS: A retrospective analysis was conducted on the prenatal diagnostic results and pregnancy outcomes of cases identified as high-risk for rare autosomal trisomies through non-invasive prenatal testing at the reproductive medicine center, Renmin hospital, Hubei university of medicine, from 2015 to 2023. RESULTS: 66 cases identified as high-risk for rare autosomeal trisomies, yielding a detection rate of 0.20% (66/33,079). 7 declined amniocentesis, while the others underwent the procedure. Prenatal diagnostic procedures did not confirm the presence of the corresponding rare autosomal trisomy in any of these cases. Among the 66 cases of rare autosomal trisomies (RATs), 5 cases were lost to follow-up, and 1 case underwent termination of pregnancy (TOP) for personal reasons, leaving 60 cases with valid pregnancy outcomes. Of these 60 valid outcomes, 50 (83.33%) resulted in full-term births, while 10 (16.67%) experienced adverse pregnancy outcomes. CONCLUSION: Prenatal diagnosis for high-risk rare autosomal trisomies typically reveals a normal karyotype with no detectable chromosomal abnormalities, and most cases can achieve full-term pregnancy outcomes. However, adverse pregnancy outcomes such as preterm birth, fetal demise, placental abnormalities, and intrauterine growth restriction are common and should be given clinical attention and consideration.

Humans

At-risk persons' attitudes toward presymptomatic and prenatal testing of Huntington disease in Michigan.

One hundred fifty-five individuals at 50% risk of inheriting Huntington disease (HD) were given a questionnaire surveying their sociodemographic characteristics, experience with HD, and attitudes toward presymptomatic and prenatal testing in HD. About two-thirds (63.2%) of the persons indicated they would take a presymptomatic test even if no specific treatment was available. Although one-half (49%) of the respondents stated they would make use of a prenatal test, only 43% of these individuals would decide to terminate a heterozygous fetus. Presymptomatic test results indicating carrier status would influence some of the respondents' decisions about marriage and childbearing. This strong interest of at-risk persons to make use of both presymptomatic and prenatal diagnosis in HD indicates the need for well-organized testing programs. These programs must be designed to address the genetic, psychosocial, and ethical issues that may arise in the use of this type of genetic test.

Adult

Detection of balanced chromosome rearrangements in 445 couples with repeated abortion and cytogenetic prenatal testing in carriers.

Cytogenetic studies were performed in 445 couples presenting because of repetitive abortion. The authors detected a balanced translocation in 19 (4.2%) of the couples, pericentric inversions in 8 (1.8%), and polymorphisms in 52 (11.4%). The results were compared with those obtained in a series of 600 consecutive normal liveborns. Significantly higher frequencies for translocations and polymorphisms were present in couples with repetitive abortion. No sex predominance in translocation carriers was observed, and reciprocal translocations were more common (16 of 19) than the robertsonian type (3 of 19). Contrary to other reports, all of the translocations and inversions were detected among couples without previous abnormal offspring. Cytogenetic prenatal testing in 17 pregnancies from a carrier parent showed that none of the fetuses had the unbalanced karyotype, 13 carried the balanced rearrangement, and 4 had a normal karyotype. Although a risk profile can be obtained for these couples, prenatal testing must be offered to avoid anxiety and unjustified pregnancy interruptions.

Abortion, Habitual

Impact of prenatal testing on maternal-fetal bonding: chorionic villus sampling versus amniocentesis.

The process of maternal-fetal attachment, considered vital for normal infant development, begins during pregnancy and can be affected by a number of external factors. In this study the impact of prenatal testing on maternal-fetal bonding was evaluated in 253 women undergoing either first-trimester chorionic villus sampling (n = 101) or second-trimester genetic amniocentesis (n = 152). The women were evaluated by means of a modification of the Cranley Maternal-Fetal Attachment Scale, administered before and after the results of the prenatal diagnostic testing were made known to them (mean gestational ages of 10.6 and 15.7 weeks for the chorionic villus sampling group and 16.5 and 21.1 weeks for the amniocentesis group). The results showed: (1) that maternal-fetal attachment begins as early as 10 weeks' gestation and increases significantly as the pregnancy progresses, (2) that maternal-fetal attachment increases significantly, once the results are known to be normal, for both groups (p less than 0.001), (3) that this increase occurs about 5 weeks earlier for patients with chorionic villus sampling in comparison to those undergoing amniocentesis (p less than 0.001). Thus, with regard to the process of maternal-fetal attachment, first-trimester chorionic villus sampling appears to be preferable to second-trimester amniocentesis.

Amniocentesis

A prenatal test for the cerebro-hepato-renal (Zellweger) syndrome by demonstration of the absence of catalase-containing particles (peroxisomes) in cultured amniotic fluid cells.

In this paper we show that whereas acyl-CoA: dihydroxyacetone phosphate acyltransferase, a membrane-bound peroxisomal enzyme, is deficient in homogenates of cultured amniotic fluid cells of fetuses with Zellweger syndrome, catalase a soluble peroxisomal matrix enzyme is present in normal amounts. Digitonin titration experiments revealed a striking difference in the percentage of particle-bound catalase in control and Zellweger amniocytes: in Zellweger amniocytes all catalase activity was found to be present in the soluble cytoplasm, (less than 5% particle-bound), whereas in control amniocytes catalase was found to be predominantly particle-bound (62% +/- 8%, n = 5). Measurement of the percentage of particle-bound catalase by means of digitonin titrations thus provides a simple prenatal test for Zellweger syndrome via the direct demonstration of the presence or absence of catalase-containing particles (peroxisomes).

Acyltransferases

Cost-effectiveness of prenatal testing for Chlamydia trachomatis.

We investigated the cost-effectiveness of strategies for screening pregnant women for Chlamydia trachomatis. Screening was not cost-effective unless certain conditions were met. Direct antigen testing of all pregnant women would be cost-effective if the test cost less than $6.30 or the prevalence of infection exceeded 6%. However, the positive predictive value of the test was only 51%. Culturing was not cost-effective until the prevalence of infection exceeded 14.8%. If a direct antigen test cost less than $3.90 or prevalence exceeded 8.7%, direct antigen testing of all women and using culture to confirm positive direct antigen tests would be cost-effective. If a direct antigen test cost $8.00 and culture cost $25.00, the excess cost of performing a direct antigen test in all women and confirming positive results with culture would be $2.09 per pregnant woman. Screening all pregnant women for chlamydia is not cost-effective, but the excess cost is modest when direct antigen tests are used.

Chlamydia Infections

Prenatal testing for birth defects and nursing practice.

Recent advances in the prenatal diagnosis of birth defects including amniocentesis, ultrasound and fetoscopy are discussed. Indications, technical considerations and limitations are presented. Parental reactions to the stresses encountered during the process of prenatal diagnosis are related. Implications are identified for nursing care practice in different clinical settings including prenatal diagnostic units, paediatric services, obstetrical services and in the community.

Chromosome Aberrations

Prenatal tests for Sanfilippo disease type B in four pregnancies.

We report the prenatal diagnosis of two fetuses with Sanfilippo disease type B. In both pregnancies there were excessive amounts of heparan sulphate in amniotic fluid and the activity of N-acetyl-alpha-D-glucosaminidase was undetectable in cultured amniotic fluid cells. The predictions were confirmed by enzyme assay of cultured skin fibroblasts from the aborted fetus or the affected infant. The disorder was excluded for two other pregnancies at risk and the predictions are considered to be correct because of the normal progress of the healthy children.

Acetylglucosaminidase