Prenatal diagnosis of morquio's disease type a (n-acetylgalactosamine 6-sulphate sulphatase deficiency)

Prenatal monitoring of three pregnancies at risk of Morquio's disease type A by determination of N-acetylgalactosamine 6-sulphate sulphatase activity in cultured amniotic cells is reported. In one pregnancy prenatal diagnosis of one affected fetus was made. Enzyme determinations in tissues of the aborted fetus confirmed the prenatal diagnosis.     

Prenatal diagnosis of Huntington's disease (HD): Experiences with six cases and PCR

In the course of a 2-year predictive testing programme for Huntington's disease (HD), six couples from a total of 52 applicants requested prenatal testing. In each case, the pregnancy was in the first or second trimester when the couples were referred for DNA diagnosis. In five cases, exclusion testing was offered; in one case, a person at risk with an increased risk of being a gene carrier requested prenatal diagnosis. In all cases, informative markers for prenatal testing could be determined. Whenever possible, the newer technique of polymerase chain reaction (PCR) for D4S125 was applied to perform rapid prenatal diagnosis. Two couples withdrew before chorionic villus sampling was undertaken; prenatal diagnosis was completed in the remaining four cases. After exclusion testing, two pregnancies were determined to have an increased risk and two fetuses to have a low risk of being HD gene carriers.     

Prenatal detection of cystic fibrosis; comparative study of maltase and alkaline phosphatase activities in amniotic fluid

The potential value of microvillar enzymes in the prenatal diagnosis of cystic fibrosis (CF) has previously been demonstrated and is corroborated in the present comparative study. Maltase and alkaline phosphatase (ALP) activities were studied in the amniotic fluids of 57 pregnancies with a 1 in 4 risk for CF or with a known CF outcome and in 489 controls. A simple assay for maltase activity (MU-maltase) with the fluorogenic substate 4-methylumbelliferyl α-glucoside, offers great technical advantages and an at least equal detection rate of CF, when compared to the previously used test with maltose as substrate. Intestinal ALP was estimated either as phenylalanine inhibitable activity (PI-ALP) or as the proportions of residual activity in the presence of the inhibitors phenylalanine or homoarginine. MU-maltase and PI-ALP appeared the most successful methods: both tests were able to detect 14 of the 16 (88 per cent) pregnancies with fetal CF. Each of the two tests alone also allowed a correct prediction in 24 of the 25 pregnancies at risk but with normal outcome; however all 25 cases could be correctly predicted by a combined evaluation. It is suggested that more than one intestinal enzyme activity should be evaluated to allow optimal results in the prenatal monitoring of pregnancies at high risk for CF.     

Huntington disease–unaffected fetus diagnosed from maternal plasma using QF-PCR

The discovery of fetal DNA in maternal plasma from early pregnancies has led to new opportunities for clinical application. In the last few years there have been numerous reported applications, mainly fetal gender and RhD genotyping. The prenatal diagnosis of some inherited genetic diseases such as Huntington disease is also very frequently required in the prenatal diagnosis routine. We have successfully diagnosed, with a non-invasive procedure, an unaffected HD fetus at the 13th week of gestation using fetal DNA from maternal plasma and the quantitative fluorescent PCR method, which is one of the most sensitive ways to detect fetal DNA in maternal plasma at such an early time of gestation. Copyright © 2003 John Wiley & Sons, Ltd.     

Prenatal detection of free sialic acid storage disease: genetic and biochemical studies in nine families

Sialic acid storage disorders, Salla disease (SD) and a severe infantile form of disease (ISSD), are recessively inherited allelic lysosomal storage disorders due to impaired egress of free sialic acid from lysosomes. Fourteen pregnancies at risk of adult-type free sialic acid storage disease, SD, were monitored by sialic acid assays, genetic linkage or mutation detection analyses using chorionic villus samples. Three affected and 12 unaffected fetuses were identified. The first studies were based on the sialic acid assays alone, but the location of the gene enabled the use of genetic linkage analysis and, more recently, the identification of the SLC17A5 gene and disease-causing mutations added yet another possibility for prenatal studies. A missense mutation 115C→T (R39C) is present in 95% of all Finnish SD alleles, providing an easy and reliable means of diagnostic studies. Both molecular and biochemical (sialic acid assay) studies can be used for prenatal diagnosis of free sialic acid storage diseases. Copyright © 2001 John Wiley & Sons, Ltd.     

First trimester diagnosis of Gaucher disease in a fetus with trisomy 21

A 38-year-old lady, who had a previous infant with type 2 Gaucher disease, underwent prenatal diagnosis by chorionic villus sampling at 9 weeks' gestation. Results on the fresh villus revealed a 47,XY,+21 karyotype and a marked deficiency (2 per cent of control) of β-glucosidase activity. Following termination, villus material was cultured which initially revealed only a partial enzyme deficiency and a normal female karyotype, i.e., maternal cells. A subsequent culture contained 47,XY, + 21 cells which were deficient in β-glucosidase activity, thus confirming the diagnosis. The results in this interesting case illustrate the potential dangers of maternal cell contamination in cultured villus cells.     

Prenatal diagnosis of sanfilippo disease type C using a simple fluorometric enzyme assay

A new fluorogenic substrate, 4-methylumbelliferyl β-D-glucosaminide, was used for the assay of acetyl CoA:glucosaminide N-acetyltransferase in chorionic villi, cultured villus cells, and amniocytes. Optimal conditions for the assay and the ranges of enzyme activity were established for the various types of fetal cells. This simple fluorometric assay provides a reliable method for early prenatal diagnosis of Sanfilippo disease type C which is more convenient than current methods using radiolabelled substrates. The method was applied to amniotic fluid cells and fetal fibroblasts from an at-risk pregnancy in which an affected fetus was diagnosed by two-dimensional electrophoresis of glycosaminoglycans in the amniotic fluid.     

Prenatal diagnosis of atypical tay-sachs disease by chorionic villi sampling

We studied a family at risk for atypical TSD in which the index case showed, clinically, a late onset and a gradual psychomotor deterioration and biochemically, a residual hex. A activity in leucocytes. Two prenatal diagnoses of affected fetuses were made in this family, The first one on amniotic cells, the second one on trophoblast biopsy samples. Both of them were confirmed after abortion on cultured cells. Prenatal diagnosis of TSD, even of some atypical forms is possible using trophoblast biopsy, but formal confirmation should be obtained on cultured trophoblasts.     

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-α-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.     

First-trimester biochemical and molecular diagnoses using chorionic villi: High accuracy in the U.S. collaborative study

The accuracy of biochemical and molecular prenatal diagnoses using chorionic villi as the fetal source was assessed by seven centres participating in the NICHD collaborative study on the safety and accuracy of chorionic villus sampling (CVS) and amniocentesis. Of 601 pregnancies studied, biochemical methods were used to determine the diagnosis in 283 fetuses at risk for 35 different metabolic disorders. Fifteen different lysosomal storage diseases accounted for 81 per cent of the biochemical prenatal diagnoses performed, with 57 per cent of these pregnancies at risk for Tay-Sachs disease. No errors were made in the biochemical diagnoses that predicted affected or unaffected fetuses. However, the diagnoses of certain disorders (e.g., mucopolysacchariodosis type IH, metachromatic leukodystrophy, and Krabbe disease) occasionally required confirmatory studies in cultured amniocytes because the enzyme results were inconclusive in direct and/or cultured villi or due to the presence of a pseudodeficiency allele. Of these, only the diagnosis of a fetus at risk for Krabbe disease remained inconclusive after special studies to discriminate between mutant and pseudodeficiency alleles. Recombinant DNA techniques were used to predict the diagnosis of 318 fetuses at risk for 16 different disorders in which the defective disease gene could be detected either directly or by linkage analysis to a nearby polymorphic marker. Of these, 32 per cent were for haemoglobinopathies, 25 per cent for cystic fibrosis, 24 per cent for Duchenne or Becker muscular dystrophy, and 7 per cent for haemophilias. Pregnancies at risk for known disorders with specific molecular lesions (e.g., sickle cell disease) were accurately diagnosed in direct and/or cultured villi. Diagnoses requiring analyses with closely linked polymorphic markers were occasionally uninformative or inconclusive. Maternal contamination was not reported in any biochemical or molecular-based diagnosis. These studies document the high accuracy and rapidity of both biochemical and mutation-specific prenatal diagnoses with direct and cultured chorionic villi.     

First trimester diagnosis of Wolman's disease

Wolman's disease was diagnosed in the first trimester of pregnancy by the direct demonstration of acid lipase deficiency in chorionic villi. The diagnosis was confirmed by studies on cultured chorionic villus cells and fetal skin fibroblasts. Acid lipase activity was assayed with both 4-methylumbelliferyl-palmitate and radiolabelled cholesterol oleate as substrates. The higher specificity of the enzyme for the latter, natural, substrate makes it superior in prenatal diagnosis.     

Prenatal molecular diagnosis of gaucher disease

Prenatal diagnosis of Gaucher disease, the most prevalent glycolipid storage disease, is based on a reliable enzyme assay of cells from amniocentesis or chorionic villous samples. However, this method cannot differentiate among the various forms of the disease. This report details four cases of prenatal diagnosis of Gaucher disease, three of which predate the use of molecular diagnosis. DNA mutation analysis to determine the genotype was predictive of the phenotypic status of the fetus and conformed to the genotype of an affected proband where available.     

Carrier detection and prenatal diagnosis in Norrie disease

We report the use of DNA probes to determine carrier status in three young women from a large kindred with Norrie disease. One of the women requested prenatal diagnosis during pregnancy. In this pedigree, Norrie disease was not characterized by a deletion at DXS7.     

Mutation analysis for prenatal diagnosis and heterozygote detection of Gaucher disease type III (norrbottnian type)

A single base substitution in exon 10 of the glucocerebrosidase gene was detected in families affected by Gaucher disease (GD) type III. This mutation, which results in the substitution of proline for leucine in position 444 of glucocerebrosidase, has been shown to result in type III GD in a Swedish population. Three fetuses at risk for GD type III were diagnosed as homozygous for the mutation and the pregnancies were terminated. In a fourth pregnancy, one parent was excluded as being a carrier and the risk of having a child affected by GD was ignored. Direct analysis of common mutations causal to GD is now available and improves prenatal diagnosis in families where the molecular defect has been characterized.     

Prenatal diagnosis of a lethal form of Netherton syndrome by SPINK5 mutation analysis

Netherton syndrome (NS) is a severe autosomal recessive ichthyosis with no specific treatment or prenatal diagnosis available at present. The recent identification of SPINK5, which encodes a serine protease inhibitor, as the defective gene enables DNA-based prenatal diagnosis to be carried out. Here we report the first direct molecular prenatal diagnosis of a lethal form due to a recurrent SPINK5 mutation in three consanguineous Turkish families. XmnI restriction enzyme digestion and DNA sequencing demonstrated that each deceased affected child was homozygous for mutation 153delT inherited from each parent. Analysis of fetal DNA from amniotic fluid cells in Family 1 and from a chorionic villus sampling in Family 3 showed that the fetus was heterozygous for 153delT in both cases. The pregnancies were carried to term and the newborns were unaffected. In Family 2, fetal DNA analysis from chorionic villus biopsy showed in a first pregnancy that the fetus was homozygous for 153delT. The pregnancy was terminated at 13 weeks and DNA analysis of fetal keratinocytes confirmed the prenatal prediction. In a second pregnancy in Family 2, fetal DNA analysis showed heterozygosity for 153delT, and the pregnancy was continued. Direct SPINK5 mutation analysis in families at risk for NS represents the first early, rapid and reliable method for prenatal diagnosis of this life-threatening form of ichthyosis. Copyright © 2002 John Wiley & Sons, Ltd.     

Prenatal diagnosis of morquio disease type a using a simple fluorometric enzyme assay

A new fluorogenic substrate, 4 methylumbelliferylβ-D-6-sulphogalactoside, was used for the assay of galactose-6-sulphate sulphatase activity in chorionic villi, cultured villus cells, and amniocytes. The fluorometric assay is much more convenient than the conventional assay using radiolabelled, sulphated oligosaccharides. Both types of substrate were used in the prenatal diagnosis of three pregnancies at risk for Morquio type A disease using amniocytes. These enzyme tests, as well as electrophoresis of glycosaminoglycans in the amniotic fluid, indicated affected fetuses in two pregnancies and a non-affected fetus in one.     

Prenatal diagnosis of congenital Chagas' disease (American trypanosomiasis)

The prenatal diagnosis of congenital transmission of Chagas' disease in a pregnant woman with the indeterminate form of the disease is reported. Sonography revealed fetal hydrops at 31 weeks' gestation. Anti-Trypanosoma cruzi IgM and IgG antibodies were negative in the fetal blood sampled by cordocentesis, but T. cruzi trypomastigotes were found in its buffy coat. Owing to anemia, in utero exchange transfusion was undertaken, but fetal demise ensued. Labor was induced and a stillborn infant weighing 2030 g was delivered. The pathological examination revealed placentitis and meningoencephalitis, myocarditis and splenitis in the stillborn fetus. Amastigotes were found in the myocardium, brain and placenta. Copyright © 2004 John Wiley & Sons, Ltd.     

Radiographic,haematological, and biochemical findings in a fetus with Caffey disease

An early case of prenatal Caffey disease is reported. Ultrasound examination performed at 20 weeks showed major angulations of long bones, but both ultrasound scan and X-rays failed to make the differential diagnosis between Caffey disease and lethal osteogenesis imperfecta. A cordocentesis allowed us to find important biological abnormalities. The pregnancy was terminated after the rapid development of hydrops fetalis. The definitive diagnosis of Caffey disease was obtained by special X-ray and pathological study.     

Prenatal diagnosis of chronic granulomatous disease (CGD) in four high risk male fetuses

Prenatal diagnosis of chronic granulomatous disease (CGD) was performed in four male high risk fetuses. The male sex was previously determined by an amniotic cell karyotype. Three kinds of test were performed on fetal blood obtained by umbilical venous puncture under fetoscopy at the 20th gestational week: nitroblue tetrazolium reduction (NBT) cytochemical test with phorbol myristate acetate (PMA) as activator; luminol enhanced chemiluminescence with activation by serum opsonized zymosan (STZ) or PMA; superoxide anion (0) production by measurement of the superoxide dismutase inhibitable reduction of cytochrome c with PMA as activator. Results were compared to those obtained in six fetuses investigated for other inherited diseases. In one case, absence of granulocyte defects was confirmed at birth. In three other cases, the tests showed deficient metabolic oxidative granulocytes. The pregnancy was terminated and the CGD diagnosis was confirmed on the products of abortion. The use of three different techniques performed on whole blood for CGD prenatal diagnosis is recommended instead of a single isolated test to ensure a higher confidence in the diagnosis.