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Argument in Favor of Reporting Adult-onset Conditions in Prenatal Diagnosis.

Prenatal genomic sequencing can detect far more than clinicians conventionally report. Whether adult-onset conditions diagnosed in the fetus should be disclosed prenatally remains debated, and most laboratories and guidelines restrict reporting to childhood-onset disease. We argue that this restriction is not supported by available evidence. Prospective parents consistently elect to receive adult-onset findings, most often to plan for a child's future health. Pediatric and newborn sequencing studies have not demonstrated the psychological, relational, or developmental harms critics anticipated, and pregnancy offers an unmatched opportunity to reach an otherwise unscreened population. Policy should be guided by informed consent and patient autonomy.

adult-onset conditions

Prenatal diagnosis of galactosemia.

Prenatal diagnosis of disorders of galactose metabolism was done in one instance in a family with a known galactokinase deficiency and in six cases in five families at risk for galactosemia. The galactokinase activity in cultured amniotic cells was found to be normal, and the diagnosis was confirmed postnatally. In the six pregnancies at risk for galactosemia, four were considered to be unaffected and two to be affected. Of the latter, one was carried to term, and the erythrocyte transferase activity of the baby was shown to be absent. The other pregnancy was terminated, and examination of fetal tissues by biochemical studies confirmed the diagnosis. This experience substantiates the concept that prenatal diagnosis of disorders of galactose metabolism is feasible.

Amniotic Fluid

The prenatal diagnosis of genetic disorders.

Prenatal diagnosis has proven highly effective in assessing the status of fetuses at risk of all cytogenetic and of several biochemical and structural disorders with genetic etiologies. The original methodology, based on the cytogenetic and biochemical analysis of cultured amniotic fluid cells, has now been complemented by a wide variety of new techniques. These include several methods for fetal visualization (sonography, fetoscopy, x ray), sampling of fetal blood, and analysis of very small quantities of material. Additional approaches, based on these and other technologies, are likely to permit the prenatal diagnosis of an ever increasing number of genetic disorders. At the same time, the number of pregnancies monitored will increase as greater resources become available and as screening programs identify couples at risk of having genetically abnormal children prior to the birth of an affected child. Prenatal diagnosis is already a powerful means of preventing the birth of individuals with significant genetic defects, thereby sparing both individuals and society from the burdens that such disorders produce. In the future, it is likely to be even more effective.

Amniotic Fluid

Prenatal diagnosis of propionic acidemia.

Prenatal diagnosis of a fetus with propionic acidemia has been accomplished by the detection of methylcitrate, a unique metabolite, in the amniotic fluid by liquid partition chromatography and gas chromatography-mass spectrometry. The diagnosis was confirmed by demonstration of deficient activity of propionyl-CoA carboxylase in cells cultured from the amniotic fluid and in fetal tissues. In two subsequent pregnancies, methylcitrate was not present in amniotic fluid. Enzyme assay indicated that one fetus was heterozygous and the other was normal, and healthy infants were born at term. The analysis of organic acids in amniotic fluid permits very rapid prenatal diagnosis, usually within 48 hours after obtaining the fluid. It may provide a general method in conditions in which an unusual metabolite can be identified.

Abortion, Therapeutic

Prenatal diagnosis of classic hemophilia.

Prenatal diagnosis of classic hemophilia (hemophilia A) in mid-trimester was achieved by means of immunoradiometric assays for factor VIII on fetal plasma and amniotic-fluid mixtures obtained by fetoscopy. Samples were analyzed from six male fetuses at risk for severe hemophilia and from nine control fetuses for which fetoscopy was carried out to attempt prenatal diagnosis of other genetic disorders. The factor VIII coagulant-antigen values for the control (non-hemophilic) samples were 17 to 94, and the factor VIII related-antigen concentrations were 50 to 155 U per deciliter. Three of the fetuses at risk for hemophilia had factor VIII values in the control range, and these infants were normal at birth. The other three fetuses had low concentrations of factor VIII coagulant antigen but normal concentrations of factor VIII related antigen. These values and the diagnoses of severe hemophilia were confirmed with blood from the abortuses.

Amniotic Fluid

Prenatal diagnosis of the hemoglobinopathies: ethical issues.

Prenatal diagnosis of the hemoglobinopathies has been increasingly reported. This article discusses those ethical issues stemming from pregnancy studies by fetoscopy or placental aspiration: diagnostic accuracy and safety for mother and fetus, abortion of the fetus diagnosed as homozygous for thalassemia or sickle cell diseases, and access to prenatal diagnosis for those who cannot afford it. The author's position on these issues attempts to mediate between the poles in current ethical debate on abortion in public policy.

Abortion, Therapeutic

Prenatal diagnosis of the Meckel syndrome.

Prenatal diagnosis of the Meckel syndrome was made at 20 weeks of gestation from the findings of a biparietal diameter smaller than expected for gestational age, a grossly raised amniotic fluid alphafetoprotein level and a rapid growth of foetal macrophages after 20 hours culture. Termination at 23 weeks of gestation resulted in a male foetus with an occipital encephalocele, microcephaly, polydactyly, and bilateral polycystic kidneys. This case report emphasies the importance for genetic counselling of delineating the Meckel syndrome from the multifactorial cases of neural tube defects, and also illustrates, at least in some cases, that the syndrome can be diagnosed in utero.

Abnormalities, Multiple

Evaluation of the efficacy of optical genome mapping in prenatal diagnosis: a retrospective cohort study.

BACKGROUND: Optical genome mapping (OGM) is an emerging cytogenetic method for concurrently detecting structural variants (SVs) and copy number variants (CNVs). However, its clinical application in prenatal diagnosis remains underexplored. METHODS: This study retrospectively evaluated the clinical validity of OGM in prenatal diagnosis by comparing with two routine genetic testing methods: karyotyping and chromosomal microarray analysis (CMA). Both positive and negative cases detected by routine genetic methods were enrolled to evaluate the technical concordance of OGM and its capability to improve diagnostic rate in negative cases. The exclusion criteria were balanced centromeric translocations, mosaic cases with cellular fractions&#x2009;<&#x2009;20%, and loss of heterozygosity (LOH)&#x2009;<&#x2009;25&#xa0;Mb. All samples subjected to OGM testing were anonymized and analyzed blindly. The results from OGM were compared with those from routine genetic testing, and statistical analyses were performed to assess technical concordance and diagnostic rate. RESULTS: Of 217 samples (166 positive samples and 51 negative samples for routine genetic testing), all were successfully tested with OGM, including 2 umbilical cord blood samples, 4 chorionic villi samples, and 211 cultured amniotic fluid samples. Of the 207 reportable chromosomal aberrations from 166 positive samples, the blinded concordance between OGM and CMA, karyotyping, and combination of karyotyping plus CMA was 97.81%, 96.36%, and 97.10%, respectively. OGM missed six aberrations initially, including one LOH, two marker chromosomes, and three microdeletions. However, after reanalysis, its concordance improved to 100% with CMA and 99.03% with karyotyping plus CMA. OGM also diagnosed one additional case of a 3-kb deletion in 51 negative samples, improving the diagnostic rate by 1.96%. Moreover, OGM reclassified the pathogenicity of two microdeletions from pathogenic to uncertain significance in 2 positive cases. Furthermore, OGM clarified the diagnosis suspected by routine genetic testing and improved diagnostic accuracy in some cases. CONCLUSION: As far as we know, this is the largest retrospective study on OGM in prenatal diagnosis, and it includes a broad range of sample types. The results showed that OGM exhibits high concordance among the tested methods and increases the diagnostic rate. Thus, OGM has the potential to become a first-line technique for prenatal diagnosis in the future.

Humans

[Clinical, preclinical and prenatal diagnosis of congenital sphingolipidoses by determining lysosomal hydrolases (author's transl)].

Sphingolipidoses in infancy and adulthood and associated metabolic disturbances are caused by a recessively inherited, circumscribed lysosomal enzyme deficiency in the catabolism of various structural tissue substances. After presenting detailed methods for the quantitative assay of activities of lysosomal hydrolytic enzymes in leukocytes, serum , fibroblasts, urine and organ tissue with the aid of synthetic chromogenic and fluorescent substrates the signigicance of these methods for clinical diagnosis, for the detection of homozygote persons before developing clinical symptoms (preclinical diagnosis), for the preventive prenatal diagnosis and forthe detection of heterozygote carriers is described for the following diseases: Deficiency of hexosaminidase A and B, deficiency of beta-glucosidase, deficiency or arylsulfatase A, deficiency of alpha-galactosidase, deficiency of alpha-glucosidase.

Clinical Enzyme Tests

[Fetography and amniography in prenatal diagnosis of genetic disorders].

68 patients were transfered to the prenatal diagnosis. Both the alpa-fetorotein-estimation and the fetography or amniography were performed in 13 patients. The indication for fetography is the exclusion of neural tube defects and other serious visible defects. The amniography can especially carried out in the prenatal diagnosis of defects of intestinal tract. A program is proposed to the prenatal detection of neural tube defects: 1. Examination of all of the pregnacies with ultra sonic B scan. 2. At suspicions ultra sonic B scan and after birth of a child with neural tube defect alpha-fetoproteinestimation at the 16th week of pregnancy and fetography at the 24th week of pregnancy.

Amnion

Amniotic fluid alpha-fetoprotein as a marker in prenatal diagnosis of neural tube defects.

The prenatal diagnosis of anencephaly and spina bifida (neural tube defect, NTD) through amniotic fluid analysis for alpha-fetoprotein (AFP) is gradually gaining clinical recognition. AFP concentrations were determined in 237 amniotic fluids from normal pregnancies ranging between 7 and 42 weeks of gestation. A steady decline in AFP from 26 mug/ml at 7-9 weeks to 155 ng/ml at term is observed. AFP concentration was determined in 35 amniotic fluids from 33 confirmed neural tube defective pregnancies. In 14 cases where amniotic fluid was examined prior to the 26th week of gestation. AFP was markedly elevated when compared with the normal range of the same gestational period. In 21 amniotic fluids past the 26th week, 17 cases (85-) had markedly elevated AFP levels; however, 2 cases of anencephaly, 1 of spina bifida, and 1 of hydrocephaly gave levels within the normal range. It is concluded that elevated AFP in the amniotic fluid is a reliable but nonspecific marker for open neural tube defects prior to the 26th week of pregnancy, but may become normal after the 26th week in a small percentage of patients.

Amniotic Fluid

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

An automatic system for chromosomal analysis applied to prenatal diagnosis.

Computer-assisted metaphase analysis for prenatal diagnosis can be economically performed by a preexisting hardware-software system. The program can be run by technician-level (i.e. nonspecialist) personnel who can opt for the automatic operational mode for good quality metaphases or for the semimanual mode for problem metaphases (numerous superpositions, artifacts, etc.). The karyotype can be obtained in conversational mode. Hardcopy output is available for all modes.

Chromosomes

Prenatal diagnosis of congenital adrenal hyperplasia.

The accurate prenatal diagnosis of 21-beta-hydroxylase deficiency, based on amniotic fluid levels of 17-hydroxyprogesterone, is documented for a fetus 14 1/2 weeks old. In addition, family HLA genotyping data are consistent with the purported linkage between the HLA locus and the locus for 21-beta-hydroxylase.

Adrenal Hyperplasia, Congenital

Prenatal diagnosis of beta-thalassaemia and sickle-cell anaemia. Experience with 24 cases.

Prenatal diagnosis of beta-thalassaemia and sickle-cell anaemia was attempted in 24 pregnancies. Adequate amounts of fetal blood (for studying globin-chain synthesis) were obtained in 22 cases. 4 cases of homozygous beta-thalassaemia and 2 of sickle-cell anaemia were diagnosed. The difference between the homozygous and non-homozygous states was well defined. Fetal bleeding from cord puncture and amnionitis resulted in the loss of three fetuses, and methods to avoid these complications are being devised. It is concluded that prenatal diagnosis of disorders of beta-globin synthesis is feasible.

Anemia, Sickle Cell

[Risks in amniocentesis for prenatal diagnosis of genetic defects].

In 139 patients for prenatal diagnosis 186 amniocenteses were required. The repetiion of amniocentesis followed in 12.3% due to failure of cell growth, in 1.1% due to failure to obtain fluid, and in 10.2% to performe the fetography. In 3 pregnant women 2 repetitions were indicated. Although the amniocentesis were performed without ultrasound, in 92% the first insertion of needle were already succeeded in obtaining fluid. In repeated amniocenteses no significant differences were found. Brownish fluid were observed in 4.7% of the first amniocentesis. With 24.4% it was significantly more frequent in the repeated amniocenteses. Bloody taps appeared in each fifth puncture, but only in 2.8% blood fluid were also withdrawed for cell culture. 82.9% of the first amniocentesis followed between 16 and 19 week's gestational age and the result was present after 20.3 days on an average. The abortion rate was 4.3%. Among the newborns one hydrocephalus with questionable needle mark, one microcephalus and one further child with questionable needle mark were found. In one duodenal atresia and in one achondroplasia an inconclusive result was obtained. Two erroneous diagnoses of sex occurred and no diagnosis was obtained in two women.

Abortion, Spontaneous