Chorionic Villous Biopsy Research Articles

Newborn with Failure to Thrive and Diarrhea.

Newborn with Failure to Thrive and Diarrhea.

Prenatal diagnosis of sickle cell disease by the technique of PCR.

Sickle cell disease (SCD) is prevalent in Central India and causes major morbidity and mortality. There is a lack of prenatal diagnostic facility near population affected with SCD. This is the pilot study in our region with the aim to establish prenatal diagnostic facility for the couples carrying sickle cell gene in Central India, in order to help them take an informed decision regarding fetus affected with SCD and also to calculate sensitivity of polymerase chain reaction (PCR) technique in our set up with follow up high performance liquid chromatography (HPLC) of baby's blood sample. Fetal sampling was done by chorionic villous biopsy. Extracted DNA was subjected to amplification refractory mutation system (ARMS-PCR) to detect sickle cell mutation (GAG→GTG) in the sixth codon of β globin gene. Follow-up HPLC was done to detect baby's Hb pattern. Prenatal diagnosis of sickle cell anemia was offered in total 37 cases out of which one (2.7%) fetal sample was inadequate. Total 26 (70.27%) fetuses had AS Hb genotype, 3 (8.11%) had AA Hb genotype and 3 (8.11%) had SS Hb genotype while remaining 4 (10.81%) were given AA/AS Hb genotype. All couples with SS fetuses opted for MTP. Follow up HPLC was performed in 24 cases, out of which 18 (75%) were correlated and 6 (25%) were mismatched. In present study sensitivity of ARMS-PCR was 75%. ARMS-PCR is a simple technique to be established initially for providing rapid prenatal diagnosis to the couples with known sickle cell mutation. The sensitivity of ARMS-PCR can be increased by using suitable techniques to detect maternal cell DNA contamination.

Challenge of 21st Century to integrate the reproductive technologies concerning the beginning of human life

DOI: http://dx.doi.org/10.3329/bioethics.v3i1.10865Bangladesh Journal of Bioethics 2012; 3(1):3

Prenatal screening for β-thalassemia major reveals new and rare mutations in the Pakistani population

β-Thalassemia is the most common genetic disorder in Pakistan, where more than 6000 affected children are born annually, and the carrier population is around 10 million. The objective was to study β-globin gene mutations in chorionic villous biopsy samples. Prenatal screening of 383 pregnant women between 2003 and 2010 was carried out using a panel of 13 mutation primers and amplification refractory mutations system (ARMS)-PCR. In addition, DNA sequencing was used to confirm uncharacterized mutations and in some cases fetal disease status was confirmed by linkage analysis. Families enrolled in this study represented major ethnic groups in Pakistan. Of the 13 mutations tested, three mutations accounted 71% of the total, including IVS1-5(G-C)[HBB:c.92+5G>C], codon 8/9(+G) [HBB:c.27_28insG] and del 619[NG_000007.3:g71609-72227del619]. Mutations in four uncharacterized samples were later confirmed by DNA sequencing as -88(C-T)[HBB:c.-138C>G], -90(C-T)[HBB:c.-140C>T] and codon 59(+T)[HBB:c.178_179insT]. To our knowledge, this is the first report of these mutations in Pakistan. Moreover, 19.2% fetal samples were normal and 52.3% heterozygous, whereas 26.4% were affected with thalassemia major. IVS1-5:IVS1-5 was the most common genotype in fetal samples. Prenatal diagnosis of β-thalassemia using ARMS PCR is an efficient approach for reducing the burden of this disease in Pakistan. In addition, rare mutations reported in this study should be incorporated in the diagnostic strategy.

Use of HbA estimation by CE-HPLC for prenatal diagnosis of β-thalassemia; experience from a tertiary care centre in north India: a brief report

Prenatal diagnosis (PND) of β-thalassemia is offered by DNA based mutation analysis at 10–12 weeks gestation using chorionic villous biopsy specimens. Most centers offering PND search for five common mutations prevalent in India, which cover more than 90% of patients. However in those families where the mutation cannot be identified in the parents, PND becomes difficult by mutation detection. The technique thus followed is estimation of globin chain synthesis ratio in second trimester cord blood samples. However, this technique is cumbersome and not available in most of the centres. We evaluated 112 cord blood samples (74 were informative) for analyzing hemoglobin A (HbA) levels by cation-exchange high performance liquid chromatography (CE-HPLC) using the BioRad β-thal short program between 18 and 22 weeks of gestation. A normal range for the population was calculated by running 14 cord blood samples of non-thalassemic abortuses of the same gestation. A 6 month post-natal follow-up was possible in 18 cases. All but one of these corroborated their PND.

Prenatal dexamethasone treatment of fetuses at risk for congenital adrenal hyperplasia: benefits and concerns

Virilization due to congenital adrenal hyperplasia (CAH) can effectively be prevented or diminished by prenatal dexamethasone given to the mother. This treatment, which should only be considered in families with a previous child with a virilizing form of the disease, has to start already at 6–7 weeks of gestation. Thus, the treatment has to be given ‘blindly’ to all mothers at risk until the diagnosis of an affected female can be ascertained by analysis of DNA from a chorionic villous biopsy, which cannot be performed until the 10th week. Since CAH is inherited as an autosomal recessive disease and only affected girls benefit from the treatment, seven out of eight fetuses are treated unnecessarily. This makes it especially important to monitor possible side effects. Adverse effects on brain and kidneys have been shown in animals exposed to large doses of dexamethasone during the second trimester. Too few follow-up human studies are reported to date to allow definite conclusions on possible side effects in man. Therefore, treatment should be done within controlled clinical studies.

DIFFICULTIES AND DILEMMAS IN THE MANAGEMENT OF CONGENITAL ANOMALIES IN TWIN PREGNANCY

SUMMARYBoth the incidence of twin pregnancy and the demand for prenatal diagnosis are increasing. Unfortunately, biochemical screening and ultrasound scanning are less reliable for prenatal diagnosis in twin pregnancies than in singletons. Amniocentesis and chorionic villous biopsy are usually diagnostic in singleton pregnancies but may be marred by sampling errors in twin gestations. Where a congenital anomaly has been diagnosed in a twin pregnancy, difficult decisions may have to be made, especially if one twin is unaffected. In these cases, special skills are required to ensure that adequate information, psychological support and optimal medical care are provided.

324 PRENATAL DIAGNOSIS OF X-LINKED LYMPHOPROLIFERATIVE DISEASE USING POLYMERASE CHAIN REACTION

X-linked lymphoproliferative disease (XLP) is a rare recessive immunodeficiency, particular to Epstein-Barr virus (EBV) infection.Patients and results: XLP was diagnosed in a German family, where two boys died from overwhelming infectious mononucleosis at the age of 6 months and 2,5 years, respectively. By haplotype analysis two sisters were diagnosed not to be carriers with a probability of > 99%. When the mother, who was an obligate carrier for XLP, became pregnant again, she and her husband requested prenatal diagnosis for XLP. Chorionic villous biopsy (CVS) was performed at 13 weeks of gestation. The fetus was found to be male by cytogenetic analysis.DNA analysis by polymerase chain reaction (PCR) with polymorphic X-chromosomal markers flanking the XLP gene locus proximally (DXS424, Xq24-q25, theta 0.13) and distally (HPRT, Xq26.1, theta 0.08) revealed the same haplotype in the fetus and in one boy with XLP. Thus, the fetus carried also the XLP mutation with a probability of > 99%.The parents were against a prolongation of the pregnancy. At the 16th week of gestation a therapeutic abortion was performed.Conclusion: PCR analysis with DXS424 and HPRT allows fast and reliable prenatal diagnosis of XLP in informative families.

Prenatal diagnosis and therapy of adrenogenital syndrome with 21-hydroxylase deficiency

Genetic counselling of the parents is prerequisite before prenatal diagnosis and prenatal therapy of CAH. Today, chorionic villous biopsy with DNA probe is the method of choice to identify homozygous CAH-fetuses. The aim of prenatal therapy is to prevent intrauterine virilization of the external genitalia in affected female fetuses. Therefore, dexamethasone (3 x 0.5 mg/d p.o.) is given to the mother immediately when pregnancy is confirmed, before prenatal diagnosis and karyotyping is possible. After the result of prenatal diagnosis, treatment is continued until term only when the fetus is affected and female. Prenatal diagnosis and effective treatment of female CAH fetuses greatly reduces the need for corrective surgery and thus helps to alleviate anxieties of prospective parents and therefore encourages further pregnancies. However, prenatal treatment of CAH to date still is an experimental therapy [corrected].

Parental attitudes to prenatal information about the sex of the fetus.

Women undergoing prenatal diagnosis (n = 198) with amniocentesis or chorionic villous biopsy participated in a study of attitudes to information about the sex of the fetus. The women completed two questionnaires on different occasions and about one fourth of them were also interviewed. Furthermore, 20 of the women's consorts were interviewed. The possibility of obtaining information about the sex of the fetus was reported as unimportant for most of the women (78%). Nevertheless, 58% of them wanted to have the information. In the questionnaires, most of the women (84%) rejected the idea of having a legal abortion because of the fetus's sex. In a discussion during the interview, only 33% of the men and women dismissed the probability that in some situations, parents-to-be might wish to choose the sex of their child and to do so by means of prenatal diagnosis. At the same time, 57% of the participants deprecated this use of the diagnostic technique. Thus the participants' answers were contradictory, indicating split attitudes to this problem. The results suggest that it is possible that people may wish to use PND to select the sex of their child. At the same time the way of answering indicates that there is a moral dilemma.

First trimester diagnosis of Pompe's disease (glycogenosis type II) with normal outcome: assay of acid alpha-glucosidase in chorionic villous biopsy using antibodies.

Prenatal diagnosis of glycogenosis type II was performed by direct assay of acid alpha-glucosidase (EC 3.2.1.20) in chorionic villous biopsy obtained by transcervical cannula aspiration from a pregnancy at risk in the 10th week of gestation. The exact value of the enzyme activity estimated by the use of antibody preparations for purified human liver acid alpha-glucosidase was in the heterozygous range, and so the homozygous enzyme deficiency could be excluded. The subsequent analysis of cells cultured from amniocentesis sampling in the 18th week of gestation resulted in a similar outcome. The study with antibodies showed that in 23 control chorionic villi obtained during gestational ages between 7-13 weeks, 1-15% of the total alpha-glucosidase activity at pH 4.0 were due to renal or neutral enzyme. This indicates that it may be important to employ antibodies for prenatal diagnosis using chorionic villous sampling. A healthy and unaffected boy was born. The biochemical values obtained from an umbilical blood specimen were in accordance with the results of the prenatal diagnosis.