Measurement of fetal urine production in mild infantile polycystic kidney disease—A case report

It is generally recognized that the sonographic findings of infantile polycystic kidney disease (IPKD) are bilaterally enlarged kidneys, oligohydramnios, an absent fetal bladder, and the typical kidney texture. Since there is a broad spectrum of renal compromise with IPKD, in utero diagnosis is thought to be limited to the severe forms. This paper reports a mild case of IPKD, where the in utero diagnosis was established by measuring fetal urine production and amniotic fluid volume serially during pregnancy, and by ultrasonographic examination of fetal kidneys.     

Prenatal diagnosis of pseudo arylsulphatase a deficiency

Prenatal diagnosis was performed on a pregnancy at risk for metachromatic leukodystrophy (MLD) in a family with the pseudo arylsulphatase A deficiency trait. Extracts of cultured amniotic fluid cells were deficient in arylsulphatase A indicating that the fetus was either affected with MLD or had the benign pseudodeficiency trait. In the cerebroside sulphate loading test, the at risk cells hydrolysed sulphatide like control cultured amniotic fluid cells implying that the fetus had pseudodeficiency. The pregnancy was carried to term and a male child was delivered. Placenta, urine and fibroblasts had very low activities of arysulphatase A. However, no sulphatide could be detected in urine and growing fibroblasts responded normally in the cerebroside sulphate loading test, suggesting pseudodeficiency. At 29 months, the infant is healthy and shows no stigmata of MLD. The prediction based on the results of the cerebroside sulphate loading test on cultured amniotic fluid cells appeared to be borne out.     

Fetal tissue involvement in the late infantile type of neuronal ceroid lipofuscinosis

Prenatal diagnosis in a pregnancy at risk for late infantile neuronal ceroid lipofuscinosis (Batten's disease) was undertaken at 17 weeks' gestation by ultrastructural examination of amniotic fluid cells. The presence of curvilinear profiles indicated an affected fetus and the diagnosis was confirmed, after the pregnancy was terminated, by the finding of many typical curvilinear profiles in multiple tissues which included skin, amnion, umbilical vessels, blood, liver, and brain. Comparison between the involved cells in the amniotic fluid and fetal tissues suggests that these cells are probably derived from the periderm, and possibly also from the amnion. The prominent presence of cytosomes in the periderm and intermediate cells of the fetal epidermis and occasionally also in the endothelial cells of the dermis suggests that fetal skin may be a useful alternative site for assessing fetal involvement. Control specimens of the amniotic fluid, fetal skin, amnion, and liver showed no similar cytosomes. However, some control amniotic fluid samples did contain cells with large collections of irregular trilaminar membranes, and these could be open to misinterpretation. It is important that only typical curvilinear profiles are considered as an indication of an affected pregnancy.     

Prenatal diagnosis and confirmation of infantile sialic acid storage disease

Amniocentesis was performed in a pregnancy at risk for infantile sialic acid storage disease. Greatly elevated levels of free sialic acid were found in cell-free amniotic fluid as well as in cultured amniotic cells from the fetus at risk. After incubation of the cultured amniocytes with fetuin labelled in its sialic acid moiety, pulse and chase experiments respectively showed accumulation and impaired release of TCA-soluble radioactive material in the amniotic cells at risk. These data thus clearly indicated that the fetus was affected. After pregnancy termination, ultrastructural studies of fetal organs and placenta showed a generalized storage picture characterized by clear membrane-bound inclusions. The diagnosis was further confirmed by the finding of greatly increased amounts of free sialic acid in fetal organs and cultured fibroblasts.     

Prenatal diagnosis of free sialic acid storage disorders (SASD)

Free sialic acid storage disorders, Salla disease (SD) and Infantile sialic acid storage disease (ISSD), are lysosomal storage diseases due to impaired function of a sialic acid transporter, sialin, at the lysosomal membrane. Several mutations of the sialin gene, SLC17A5, are known, leading either to the severe neonatal/infantile disease or to the milder, adult-type developmental disorder, Salla disease. Free sialic acid accumulation in lysosomes causes increased tissue concentration and consequently elevated urinary excretion. Prenatal diagnosis of SASD is possible either by determination of free sialic acid concentration or by mutation analysis of the SLC17A5 gene in fetal specimen, in chorionic villus biopsy particularly. Both techniques have been successfully applied in several cases, sialic acid assay more often in ISSD cases but mutation analysis preferentially in SD. Sialic acid assay of amniotic fluid supernatant or cultured amniotic fluid cells may give erroneous results and should not be used for prenatal diagnosis of these disorders. The present comments are mainly based on our experience of prenatal diagnosis of SD in Finnish families. A founder mutation in SLC17A5 gene, 115C-> T, represents 95% of the disease alleles in the Finnish SD patients, which provides a unique possibility to apply mutation analysis. Therefore, molecular studies have successfully been used in 17 families since the identification of the gene and the characterization of the SD mutations. Earlier, eight prenatal studies were performed by measuring the free sialic acid concentration in chorionic villus samples. Copyright © 2006 John Wiley & Sons, Ltd.     

Prenatal diagnosis of bartter syndrome

Bartter syndrome, an autosomal recessive disorder of hyperaldosteronism and increased plasma renin, was suspected in an at-risk pregnancy due to the early occurrence of polyhydramnios. Further establishment of the diagnosis was accomplished by demonstrating increased levels of aldosterone in amniotic fluid and fetal cord blood. Electrolyte levels did not differ significantly from reported controls. It is thus suggested that polyhydramnios is the result of increased fetal urine output in Bartter syndrome and that amniotic fluid aldosterone is a reliable marker for the prenatal diagnosis of this condition.     

Apolipoproteins in human fetal blood and amniotic fluid in mid-trimester pregnancy

To examine the potential for prenatal diagnosis of genetic lipoprotein metabolic defects (e.g. abetalipoproteinemia, Tangier disease) we determined the normal concentrations of apolipoproteins (apo) A-I, A-II, B, and E in mid-trimester amniotic fluid and fetal plasma. The concentrations of apo A-I and apo A-II in amniotic fluid were 1−2 per cent of the respective levels in the mother's plasma, whereas apo B and apo E were undetectable in amniotic fluid. In contrast to amniotic fluid, all four apolipoproteins were detectable in fetal plasma, and the levels of apo A-I, apo B and apo E were in the range observed in the mothers: 160·2 ± 103·1, 59·8 ± 35·7 and 5·7 ± 3·5 mg/dl respectively (mean ± SD, n=13). The fetal plasma level of apo A-II (28·3 ± 12·4 mg/dl) was two-thirds that observed in the mother's plasma. The normal levels of these apolipoproteins in fetal plasma are well above the sensitivity of the methods, and their quantification requires only 10−20 μl of fetal plasma. Determination of apolipoproteins in fetal blood obtained by fetoscopy thus may provide a method for the prenatal diagnosis of congenital apolipoprotein deficiences.     

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.     

Maternal contamination of amniotic fluid demonstrated by DNA analysis

DNA from 16 sets of samples comprising DNA from uncultured amniotic fluid cells, cultured amniotic fluid cells, fetal tissue, and maternal blood was analysed by the polymerase chain reaction (PCR) with AC-repeat primers. The analysis was performed to investigate the presence of contaminating maternal cells in amniotic fluid which would affect the reliability of DNA studies for prenatal diagnosis. In three sets, maternal contamination of uncultured amniotic fluid cells was detected. In one of the three sets, maternal contamination was present in both uncultured and cultured amniotic fluid cells. The use of amniotic fluid cells as a source of DNA for prenatal diagnosis should be limited to cases where the purity of the DNA can be demonstrated prior to the diagnostic test being performed. This limitation in the use of amniotic fluid DNA also extends to other forms of diagnosis relying on the purity of amniotic fluid samples, particularly the new in situ hybridization methods currently being developed.     

The prenatal diagnosis of the cerebro-hepato-renal syndrome of Zellweger

The prenatal diagnosis of the cerebro-hepato-renal syndrome of Zellweger (CHRS) was made by assaying the levels of very long chain fatty acids (VLCFAs) in amniotic fluid cell cultures, obtained by amniocentesis at 16 1/2 weeks of pregnancy. The family-at-risk, because they had previously borne a child with CHRS, accepted these results as indications of an affected fetus, and chose to terminate the pregnancy at 20 1/2 weeks of gestation. The diagnosis was confirned by the phenotype of the aborted fetus and the presence of markedly elevated levels of VLCFAs in fetal liver homogenates. The prenatal diagnosis of CHRS, which can now readily be determined from amniotic fluid cell cultures, is an important step in genetic counselling of families-at-risk for this disease.     

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.     

HUMAN CHORIONIC GONADOTROPHIN AND ALPHA-FETOPROTEIN LEVELS IN MATCHED SAMPLES OF AMNIOTIC FLUID,EXTRAEMBRYONIC COELOMIC FLUID,AND MATERNAL SERUM IN THE FIRST TRIMESTER OF PREGNANCY

Separately identified samples of amniotic fluid and extraembryonic coelomic fluid obtained by high resolution transvaginal ultrasound-guided amniocentesis from 32 women between 7 and 12 weeks of pregnancy were analysed for human chorionic gonadotrophin (hCG) and alpha-fetoprotein (AFP). There was a highly significant difference between the hCG levels in amniotic fluid (median level 6.3 U/ml; range 1.6–310.0 U/ml) and those in extraembryonic coelomic fluid (median level 400.0U/ml; range 135.0–2250.0U/ml) (p<0.001; Mann-Whitney U/–test). The levels of AFP were very similar in amniotic fluid (median 26.0 kU/ml; range 10.0–116.5 kU/ml) and extraembryonic coelomic fluid (median level 24.1 kU/ml; range 12.4–94.4 kU/ml).     

Prenatal diagnosis of multiple acyl-CoA dehydrogenase deficiency: association with elevated α-fetoprotein and cystic renal changes

We report the occurrence of multiple acyl-CoA dehydrogenase deficiency (MADD) in two consecutive pregnancies in a young, Caucasian, non-consanguineous couple. In the first pregnancy, the maternal serum α-fetoprotein was elevated. A sonogram showed growth delay, cystic renal disease, and oligohydramnios; the parents decided to terminate the pregnancy. Postmortem examination confirmed the cystic renal disease and showed hepatic steatosis, raising the suspicion of a metabolic disorder. The diagnosis of MADD was made by immunoblot studies on cultured fibroblasts. In the subsequent pregnancy, a sonogram at 15 weeks' gestation showed an early growth delay but normal kidneys. The maternal serum and amniotic fluid concentrations of α-fetoprotein were elevated, and the amniotic fluid acylcarnitine profile was consistent with MADD. In vitro metabolic studies on cultured amniocytes confirmed the diagnosis. A follow-up sonogram showed cystic renal changes. These cases provide additional information regarding the evolution of renal changes in affected fetuses and show a relationship with elevated α-fetoprotein, which may be useful in counseling the couple at risk. MADD should be considered in the differential diagnosis of elevated α-fetoprotein and cystic renal disease. Early growth delay may be an additional feature. Copyright © 2001 John Wiley & Sons, Ltd.     

Rapid and radical amniodrainage in the treatment of severe twin–twin transfusion syndrome†

We have evaluated the role of a rapid and radical method of amniodrainage in the treatment of severe twin–twin transfusion. The outcome of 15 patients with severe twin–twin transfusion for which a amniodrainage was performed by means of a vacuum bottle system was compared with the outcome of 15 patients with a similar condition, matched for gestational age at the time of the initial procedure and drained using a standard procedure. In the study group the amniodrainage ended when no amniotic fluid could be aspirated, whereas the women in the standard group were drained with a syringe system and the fluid was removed until the deepest amniotic fluid pool was <8 cm. At the initial procedure, the mean volume of amniotic fluid drained was significantly (p<0.05) higher (3252 vs 2153 ml) and the length of the procedure significantly (p<0.001) shorter (21 vs 41 min) in the study group than in the standard group. The mean post-procedure amniotic fluid index was significantly (p<0.001) smaller (2.9 vs 7.7 cm) after radical amniodrainage than after the standard amniodrainage. The mean number of procedures was significantly (p<0.001) lower (1.5 vs 5.6) in the study group compared to the standard group. In the study group the mean placental thickness increased significantly (p<0.001) from 9 mm before the procedure to 49 mm after, and the overall perinatal survival rate was 80% and the proportion of pregnancies with at least one survivor was 93%. The present data indicate that early, rapid and radical amniodrainage is an effective and low-cost therapy for severe twin–twin transfusion syndrome. Compared to the standard amniodrainage technique it also appears to reduce the need for multiple procedures. Copyright © 2001 John Wiley & Sons, Ltd.     

Fetal presentation of morquio disease type A

A fetus with mucopolysaccharidosis type IV A (Morquio type A) is described. The family had one affected child exhibiting symptoms of classical Morquio A disease, and late in the subsequent pregnancy prenatal diagnosis was requested. At 23 weeks' gestation, moderate ascites was detected by detailed ultrasound scan and keratan sulphate was found in the amniotic fluid. The pregnancy was terminated by prostaglandin induction and the diagnosis of mucopolysaccharidosis type IV A was confirmed by demonstration of a deficiency of N-acetylgalactosamine-6-sulphate (GalNac-6-S) sulphatase in cultured amniotic cells and in post-mortem fibroblast cultures. The activities of β-galactosidase and arylsulphatase A were normal, ruling out Morquio disease type B and multiple sulphatase deficiency. These results indicate that mucopolysaccharidosis IV A (a disease that predominantly affects the skeletal system) may produce ascites in the fetus to such an extent that it can be detected by ultrasound.     

Influence of extracellular matrix on the proliferation of human amniotic fluid cells in vitro

Factors which influence the proliferation of human amniotic fluid cells in vitro have potential importance in reducing the time for prenatal diagnosis. Fibroblast growth factor (FGF) has been shown to be mitogenic for human amniotic fluid cells. The observation that cells which respond to FGF in vitro produce their own extracellular matrix (ECM), led to the use of an ECM as a substrate to assess proliferation. Pooled amniotic fluid cells maintained on an ECM prepared from bovine corneal endothelial cells demonstrated a significant increase in proliferation when compared with cells maintained on plastic substrate in the presence or absence of FGF. If FGF was added to cultures of amniotic fluid cells maintained on ECM, further increases in proliferation were noted compared with cells maintained on ECM in the absence of FGF. These results indicate that the substrate upon which amniotic fluid cells are maintained can have a profound influence on their proliferation.     

Prenatal diagnosis of congenital toxoplasmosis

Ninety-three pregnant women with Toxoplasma gondii seroconversion during pregnancy underwent prenatal diagnosis of fetal toxoplasmosis. The following tests were used: (1) amniocentesis for mouse inoculation (93 subjects), (2) amplification of T. gondii DNA by polymerase chain reaction (PCR) (79 subjects), and (3) cordocentesis for the detection of T. gondii-specific IgM antibodies (13 subjects). All patients had serial ultrasonographic scans to detect those fetuses with abnormalities that could be associated with congenital toxoplasmosis. Eighteen pregnancies (19.4%) had evidence of vertical transmission. A total of 11/18 (61.1%) had positive amniotic mouse inoculation test, while 10/12 (83.3%) had positive PCR results. The combination of both tests allowed the prenatal diagnosis in 17/18 infected fetuses (94.4%). All patients who underwent cordocentesis for the detection of T. gondii-specific IgM antibodies had negative results. However, in two of the above cases fetal toxoplasmosis was detected by amniotic fluid studies. In five of the infected fetuses there were abnormal ultrasonographic findings. All pregnancies with evidence of vertical transmission were terminated, whereas the remaining pregnancies proceeded normally to term. The present data showed that amniotic fluid studies, preferably PCR amplification of T. gondii DNA, are the best diagnostic tools for the detection of vertical transmission in pregnancies with seroconversion during pregnancy. Copyright © 2002 John Wiley & Sons, Ltd.     

Prenatal diagnosis of galactosialidosis

The second prenatal diagnosis of galactosialidosis is reported. Neuraminidase and β-galactosidase activities in cultured amniotic cells were deficient, this being confirmed by skin fibroblast enzyme assay on the affected fetus after interruption of the pregnancy. Cultured placental cells demonstrated the same enzyme deficiencies. Analysis of deproteinized amniotic fluid showed the presence of abnormal oligosaccharides specific for a-neuraminidase deficiency.     

Activity and multiple forms of α-L-fucosidase and hexosaminidase in chorion biopsy specimens and some fetal organs

It was shown that activities and isoenzyme patterns of x-L-fucosidase and hexosaminidase were similar in biopsy specimens of chorion obtained immediately before induced abortion in normal pregnancy and in chorion tissue itself. A comparative study of isoenzyme patterns of these glycosidases showed their similarity in chorion and human fetal kidney, liver and lungs. The data obtained may be applied to the investigation of the multiple forms of α-L-fucosidase and hexosaminidase in chorion biopsy specimens for the prenatal diagnosis of fucosidosis (α-L-fucosidase deficiency). Tay-Sachs diseases (hexosaminidase A deficiency) and Sandhoff disease (deficiency of hexosaminidase A and B).     

Amniotic fluid analysis in a fetus with laryngeal atresia

Complete laryngeal atresia is a rare congenital malformation that is known to cause hypertrophy of the fetal lung in utero. A fetus with laryngeal atresia was found to have markedly immature amniotic fluid lung maturity studies at term. Inappropriately low amniotic fluid lung maturity studies may be an important clue to the diagnosis of this condition.