Congenital erythropoietic porphyria: prenatal diagnosis and autopsy findings in two sibling fetuses.

Congenital erythropoietic porphyria is an autosomal recessive disease characterized by a deficiency of uroporphyrinogen III cosynthetase activity, with diffuse tissue accumulation of specific type I porphyrins. The diagnosis of this disease was made in two fetuses, who were siblings, and from a Caucasian nonconsanguinous family. The first fetus died in utero with hydrops fetalis and anemia, but without an etiopathogenic diagnosis. In the second case, the diagnosis was based on pink fluorescence of the amniotic fluid examined fortuitously in sunlight. DNA analysis showed that the fetus was heteroallelic for the mutation C73R. The autopsy showed brown skin, and at histological examination, porphyrin pigment was deposited in many tissues. Retrospectively, similar deposits were found in the tissues of the first fetus.

How accurate is the prenatal diagnosis of abnormal genitalia?

PURPOSE: The prenatal diagnosis of abnormal genitalia may have a major impact on prenatal counseling and postnatal outcome. We studied the accuracy and clinical implications of the prenatal diagnosis of abnormal genitalia. MATERIALS AND METHODS: Between 1991 and 1999 the prenatal and/or postnatal diagnosis of abnormal genitalia in 53 cases was made at our institution. All cases were prenatally assessed at our Obstetrics and Fetal Medicine Department. Outcome was confirmed postnatally or by a fetopathologist in the case of pregnancy termination. RESULTS: A genital anomaly was prenatally diagnosed in 43 cases and was accurate in 34, while in 9 cases anomalies were absent at birth. In 10 cases ambiguous genitalia were not detected prenatally. The primary anomalies suspected were male pseudohermaphroditism in 19 cases and female pseudohermaphroditism in 12, including 2 cases of congenital adrenal hyperplasia. Male pseudohermaphroditism was detected prenatally in 17 cases and diagnosis was confirmed at birth. Female pseudohermaphroditism was detected prenatally in 12 cases and only 5 were confirmed and the anomaly was discovered at birth in 6. The prognosis was highly altered when many malformations or aneuploidy was associated with ambiguous genitalia. Of the 15 patients with many malformations only 3 survived, and pregnancy was terminated in 3 of 4 cases of aneuploidy. CONCLUSIONS: When pseudohermaphroditism was detected in a male fetus by an experienced ultrasonographer at a tertiary center the prenatal diagnosis was accurate in 100% of cases. The prenatal diagnosis was less accurate (46% correct) in a female fetus.

Skeletal abnormalities in fetuses with Down's syndrome: a radiographic post-mortem study.

OBJECTIVE: To evaluate skeletal abnormalities on post-mortem radiographs of fetuses with Down's syndrome. MATERIALS AND METHODS: Biometrical and morphological criteria, which are used for US prenatal detection of trisomy 21, were assessed. Limb long bones, biparietal diameter (BPD)/occipito-frontal diameter (OFD) ratio, ossification of nasal bones and appearance of the middle phalanx of the fifth digit (P2) in 60 fetuses with Down's syndrome were analysed and compared with 82 normal fetuses matched for gestational age (GA) from 15 to 40 weeks' gestation (WG). RESULTS: We observed reduced growth velocity of limb long bones during the third trimester in both groups, but the reduction was more pronounced in the trisomic group. Brachycephaly was found as early as 15 WG in Down's syndrome and continued throughout gestation (sensitivity 0.28, specificity 1). Ossification of the nasal bones, which can be detected in normal fetuses from 14 WG, was absent in one quarter of trisomic fetuses, regardless of GA. The middle phalanx of the fifth digit was evaluated by comparison with the distal phalanx (P3) of the same digit. We found that P2 was not ossified in 11/31 trisomic fetuses before 23 WG, and was either not ossified or hypoplastic in 17/29 cases after 24 WG (sensitivity 0.56, specificity 1). CONCLUSIONS: Three key skeletal signs were present in trisomic fetuses: brachycephaly, absence of nasal bone ossification, and hypoplasia of the middle phalanx of the fifth digit. All these signs are appropriate to prenatal US screening. When present, they fully justify determination of the fetal karyotype by amniocentesis.

Outcome of posterior urethral valves: to what extent is it improved by prenatal diagnosis?

PURPOSE: To assess the impact of prenatal diagnosis and evaluation on the outcome of posterior urethral valves we studied all cases of valves detected prenatally, including cases of pregnancy termination due to posterior urethral valves. MATERIALS AND METHODS: Between 1989 and 1996, 30 neonates with prenatally detected posterior urethral valves were treated at our hospital. The prenatal parameters analyzed were age of gestation at diagnosis, ultrasonographic appearance of renal parenchyma and amniotic fluid volume. Fetal urine was analyzed in 9 cases. We reviewed the outcome of 10 neonates treated for posterior urethral valves which were not diagnosed prenatally during the same period. RESULTS: Of the 30 neonatal survivors 6 (20%) had renal failure, including end stage renal disease in 2, after a mean followup of 4 years. Renal failure developed in 2 of 5 cases detected before 24 weeks of gestation, in 1 of 6 with oligohydramnios and in 2 of 5 with abnormal parenchymal renal ultrasound. Normal parenchymal ultrasound and amniotic volume could not predict for good outcome. Renal failure developed in 2 of 7 cases predicted by fetal urinalysis as good prognosis and in 1 of 2 cases predicted as poor prognosis. Pregnancy was terminated for posterior urethral valves in 5 cases based on prenatal criteria of severe renal impairment. Considering these cases as poor outcome, the rate of poor prognosis increased from 20 to 31%. Among the 10 neonates without a prenatal diagnosis of posterior urethral valves renal failure developed in 2 (20%), including end stage renal disease in 1. CONCLUSIONS: When negative parameters were absent and/or fetal urine predicted good outcome there were no cases of end stage renal disease in early infancy, which was a significant help in parent counseling. The predictive value of the currently available prenatal parameters needs to be updated with larger series specifically dealing with posterior urethral valves. According to the current data, the outcome of posterior urethral valves is not yet significantly improved by prenatal diagnosis.

The human SRY protein is present in fetal and adult Sertoli cells and germ cells.

Sex determination in mammals is controlled by the Y chromosome located SRY gene. Despite recent advances towards understanding the mechanisms that regulate sex determination in mammals, the expression profile of the SRY protein in human tissues is unknown. To localize the SRY protein and determine its cellular distribution, we prepared monoclonal antibodies (mAb) against the recombinant SRY protein. One antibody, LSRY1.1, recognizes a SRY-specific epitope and was used to localize the protein in different cells and tissues. The mAb recognizes a protein of 27 kDa in total lysates of HeLa SRYB3 cells. Immunocytochemical staining showed a nuclear localization of the protein. Immunohistochemical studies performed on gonadal tissue of a fetus, a one month-old boy and an adult man, demonstrated the presence of SRY protein in the nucleus of Sertoli and germ cells. In addition two 46,XX SRY(+) males had the SRY protein in their gonadal tissues. All other samples were negative, including all female tissue studied and the testis of a 46,XX SRY(-) male. The presence of SRY protein in fetal and adult gonadal tissues including germ cells suggests that SRY may have other male-specific functions in addition to sex determinism.

Fatty acid desaturase activities and polyunsaturated fatty acid composition in human liver between the seventeenth and thirty-sixth gestational weeks.

OBJECTIVE: The aim of the study was to characterize n-3 and n-6 fatty acid delta5- and delta6-desaturase activities and their time course variations in human fetal liver between the 17th and 36th gestational week. STUDY DESIGN: Twenty-one biologic samples were obtained after legally approved medical abortion, according to French law. The desaturase activities were measured in the 21 liver samples by a radiochemical method by means of reverse-phase high-performance liquid chromatography. The fatty acid composition (percentage by weight) of liver phospholipids was assessed in 16 samples by gas-liquid chromatographic analysis. RESULTS: Both delta5- and delta6-desaturase activities were significantly expressed between the 17th and 36th gestational weeks. During the second trimester n-6 fatty acid delta5- and delta6-desaturase activities showed opposite patterns of variation; both then remained stable between the 25th and 36th weeks. Delta6-desaturation was higher in n-3 than n-6 fatty acids and peaked at the 18th gestational week. The percentages of linoleic and docosahexaenoic acids in liver microsomes were positively correlated with the gestation age (P < .01), whereas arachidonic acid remained stable. CONCLUSION: Significant n-3 and n-6 delta5- and delta6-desaturase activities are expressed in human fetal liver as early as the 17th gestational week and are stable throughout the third trimester. Their theoretic capacity evaluated from in vitro measurements appears lower than polyunsaturated fatty acid requirements and is not directly related to liver microsomal membrane fatty acid composition.

Delta6- and delta5-desaturase activities in the human fetal liver: kinetic aspects.

Delta6- and delta5-desaturase activities were studied in human fetal liver microsomes obtained after legally approved therapeutic abortion. Enzyme activities were measured by a radiochemical method using reverse-phase high performance liquid chromatography (HPLC). Free and phospholipid fatty acids were assessed in each liver sample by a combination of thin-layer chromatography (TLC) and gas-liquid chromatography (GLC) procedures. The kinetic measurements showed higher delta6-desaturase activity for the n-3 series than for the n-6 series. Apparent Km of 6.5, 3.9, and 24.5 microM and Vm of 7.5, 9.1, and 24.4 pmol x min(-1) x mg(-1) were obtained, respectively, for 18:2n-6 delta6-, 20:3n-6 delta5-, and 18:3n-3 delta6-desaturases. Beyond 30, 20, and 60 microM of 18:2n-6, 20:3n-6, and 18:3n-3 concentration, respectively, the enzyme activity deviated from Michaelis-Menten kinetics, suggesting an inhibition by excess substrate which is unlikely to occur in vivo as endogenous substrate concentration is much lower. We observed a breakdown in linearity between desaturase activity and microsomal protein concentration beyond 4-5 mg microsomal protein, whatever the enzyme or substrate. Both this phenomenon and the inhibition due to excess substrate should be taken into account in the determination of delta6- and delta5-desaturase activities. Comparison of concentrations of the respective endogenous substrates and the kinetic constants of each enzyme suggested that the higher delta6-desaturase activity observed for the n-3 series than for the n-6 series is not physiologically relevant in human fetal liver.

Fetus with Casamassima-Morton-Nance syndrome and an inherited (6;9) balanced translocation.

We report on a fetus with cranio-facial anomalies, a narrow thorax, imperforate anus with cloacal cyst, and a genitourinary malformation with absent uterus, vagina, and external genitalia. Major thoracic defects were seen on roentgenographic examination, including absent vertebrae and ribs, a supernumerary vertebra, a hemivertebra, and rib fusion. These findings are compatible with Casamassima-Morton-Nance syndrome. The patient was the carrier of a translocation t(6;9)(p12;q12), inherited from the mother. Although the occurrence of this rearrangement may be coincidental, it may also indicate a possible locus for this autosomal recessive thoracic dysplasia.

Computerized microscope morphometry of umbilical vessels from pregnancies with intrauterine growth retardation and abnormal umbilical artery Doppler.

Computerized microscope morphometry was used to study cross sections from the vessels of the umbilical cord in placentas of patients with intrauterine growth retardation (IUGR) that displayed either normal or abnormal umbilical arteries (UA) Doppler flow velocity waveforms (FVW). Cords from 63 eutrophic fetuses with normal Doppler (controls), 47 IUGR fetuses with normal Doppler and 32 IUGR fetuses with abnormal Doppler underwent morphometric analysis using a highly optimized microscope environment (HOME) and "CordHOME" software. IUGR with an accompanying normal Doppler versus control showed a reduction of Wharton jelly and both the total and lumen vein areas. IUGR with an accompanying pathological Doppler showed a comparable reduction in wall thickness and areas of every vessel. These findings indicate that the hypoplastic umbilical vessels are associated with an increase in placental vascular resistance that may be the consequence of underdevelopment in response to a chronic reduction in placental blood flow.

Supratentorial parenchyma in the developing fetal brain: in vitro MR study with histologic comparison.

PURPOSE: To assess the in vitro MR signal of the developing brain through histologic comparisons. METHODS: Five healthy fetal specimens aged 16, 19, 22, 27, and 34 gestational weeks were studied in vitro using T1- and T2-weighted sequences in frontal and axial planes. Neuropathologic studies included sections in the same frontal plane. Comparison of histologic sections with measurements of the relative widths of the layers of different signal intensities enabled us to assign cellular correspondence to each MR layer. RESULTS: In the cerebral mantle, a layered pattern was observed on both T1- and T2-weighted images. In the basal ganglia, signal from the pallidum and thalamus was isointense with white matter from 16 to 22 weeks' gestation; then, from 27 and 34 weeks' gestation, the signal was relatively high on T1-weighted images and low on T2-weighted images. The neostriatum had a relatively low signal on T1-weighted images and a high signal on T2-weighted images from 16 to 27 weeks' gestation: then, at 34 weeks' gestation, the signal was relatively high on T1-weighted images and low on T2-weighted images. CONCLUSION: MR imaging can clearly show specific patterns of growing fetal brain in vitro.

Hypoxia impairs cell fusion and differentiation process in human cytotrophoblast, in vitro.

During human pregnancy, the trophoblast develops from differentiation of cytotrophoblast cells into an endocrine active syncytiotrophoblast. In culture, isolated mononuclear cytotrophoblasts aggregate and then fuse to form a syncytium, reproducing the in vivo process. In this study, we examined the effect of low oxygen tension (approximately 9%, hypoxia) compared to standard conditions (approximately 19% oxygen, normoxia) on these cellular events. Under hypoxia, syncytial formation was less frequently observed, cell staining and electron microscopy revealed that cytotrophoblasts remain aggregated, with a positive proliferative cell nuclear antigen (PCNA) immunostaining. Desmoplakin and E-cadherin, both known to disappear with cytotrophoblast fusion, showed persistent expression in hypoxic cells after 3 days of culture. In contrast, the expression of actin and ezrin, two cytoskeletal proteins, was unchanged. hCG secretion and hPL expression were both decreased in hypoxic cells, reflecting a reduced syncytial formation. Thus, on day 3, the mean values for hCG secretion were 1,100 +/- 155 and 289 +/- 26 mlU/mL in normoxic and hypoxic conditions, respectively. The reduced cell fusion process as well as hCG secretion and hPL expression under hypoxia were reversed by reoxygenation of the cells. We conclude that under hypoxia, the formation of functional syncytiotrophoblast is impaired due to a defect in the cytotrophoblast fusion process. This may explain the observation of a higher number of cytotrophoblast cells and a reduced syncytial layer in placentas of some pathological pregnancies.

Immunolocalization of vitamin D receptor and calbindin-D28k in human tooth germ.

The role of vitamin D in ameloblasts and odontoblasts has been studied experimentally in rodents. Dental dysplasias have also been reported in clinical studies of children with rickets. Vitamin D acts via a nuclear receptor which binds the major metabolite, 1,25-dihydroxyvitamin D3, and positively or negatively controls the expression of specific genes. The most extensively studied markers of 1,25-dihydroxyvitamin D3 action are calbindin-D9k, calbindin-D28k, and osteocalcin. Therefore, to study in more detail the potential role of 1,25-dihydroxyvitamin D3 in human dental development, 1,25-dihydroxyvitamin D3 receptor (VDR) was localized by immunofluorescence in forming teeth (8-26 wk of gestation). Calbindin-D28k was also mapped by immunoperoxidase in antenatal and postnatal forming and formed teeth. VDR were detected in both dental epithelium and mesenchyme of bud, cap, and bell stages of tooth germs. Nuclei of overtly differentiated ameloblasts and odontoblasts were also immunostained. Calbindin-D28k was present in differentiated ameloblasts and odontoblasts. The presence of VDR and calbindin-D28k in ameloblasts and odontoblasts suggests that 1,25-dihydroxyvitamin D3 may contribute to the regulation of enamel and dentin formation, as classically reported for bone formation. Finally, the early appearance of VDR supports the concept that 1,25-dihydroxyvitamin D3 may also control forward stages of tooth crown development in humans.

Meconium ileus and intestinal atresia in fetuses and neonates.

A collaborative study was performed to determine the different types and mechanisms of intestinal abnormalities during gestation. Cases had to fulfill one or more of the following three criteria: (1) meconium ileus, (2) intestinal stenosis or atresia, and (3) meconium peritonitis. Esophageal atresia, anorectal atresia, and abdominal wall defects were excluded. One hundred two cases were reviewed from the autopsies of 42 induced abortions, 22 stillborns, and the surgical findings in 38 neonates. Meconium ileus was detected mainly during the second trimester (28/38), and was associated with cystic fibrosis (15), fetal blood deglutition (4), infection (6), or multiple-abnormalities (10), in which three chromosomal aberrations were found. Intestinal stenosis or atresia was more commonly detected during the third trimester of gestation (46/56). Sixteen of the 30 duodenal malformations were associated with trisomy 21, whereas in the 26 small intestinal atresias, signs of distress or ischemia were most frequently detected. Only 8 of 25 meconium peritonitis cases were isolated. A total of 20 cystic fibrosis cases could be proved. In this series, functional abnormalities were observed predominantly in the second trimester and associated mainly with cystic fibrosis or amniotic fluid abnormalities. Anatomic lesions were commonly detected later on and associated with ischemic conditions, chromosomal aberrations, and even cystic fibrosis.

Increased placental antifibrinolytic potential and fibrin deposits in pregnancy-induced hypertension and preeclampsia.

Preeclampsia is characterized by maternal hypercoagulable state and intravascular coagulation, microthromboses in several organs, and impairment of uteroplacental circulation. Excessive fibrin deposition occurs in the placenta, suggesting that disorders of placental coagulation and fibrinolysis physiologic systems may have a role in hemostasis activation. Term placentas were collected from 17 hypertensive/preeclamptic women and from 17 healthy pregnant women, and processed for both histologic and hemostasis studies. Placental fibrinoid deposition was visualized by cresyl-violet staining and quantified by histomorphometric analysis. The content in hemostasis factors was measured on extracts from homogenized placentas treated by a nonionic detergent. The percentage of villi with fibrinoid deposits was higher in the diseased placentas than in controls: 13.2 +/- 11.2 versus 6.75 +/- 2.7% (p < 0.001) for the total amount of deposits; 4.8 +/- 6.7 versus 1.5 +/- 1.0% (p = 0.04) for perivillous fibrinoid deposits, which are considered as histologic markers of intraplacental fibrin. The content in type 2 plasminogen activator inhibitor (PAI-2) antigen was higher in the diseased placentas than in controls: 124 +/- 8 versus 104 +/- 6 ng/mg placental protein (p = 0.046); there was a negative correlation between PAI-2 antigen and thrombomodulin activity (r = -0.57, p = 0.02) in the diseased placentas. No significant differences were found between the two groups for placental procoagulant tissue factor and anticoagulant thrombomodulin activities, and for the content in plasminogen activators and PAI-1 antigens. Placental antifibrinolytic potential is increased in pregnancy-induced hypertension and preeclampsia. This change, and the association of the highest PAI-2 placental concentrations with the lowest concentrations of thrombomodulin, may contribute to the prethrombotic state and to the excessive placental perivillous fibrin deposition observed in these situations.

Fetal bone age revisited: proposal of a new radiographic score.

In order to establish a fetal bone age score, the post-mortem skeletal radiographs of 85 selected normal fetuses aged from 15 to 41 weeks of gestation (WG) were analysed. Twenty-eight skeletal areas were selected for which quantitative and/or qualitative criteria were defined. Each new aspect was graded and statistically tested by the stepwise linear regression method. Two modalities of scores and decreasing complexity were then designed. The use of these two scores permitted the assessment of the fetal age with r2 values of 0.97 and 0.96 (standard error of estimation of 1.19 and 1.36 WG). Applied to 15 intrauterine growth retardation (IUGR) fetuses, the age estimated by these scores was well correlated with the age obtained by extraosseous criteria of maturation. This method is proposed as a tool for determining, the fetal age during necropsy and could also be useful in US prenatal evaluation.

Alterations of human placental epidermal growth factor receptor in intrauterine growth retardation.

We studied human placental microvillous EGF receptor (EGFR) and its relationship with maternal and placental features in 14 cases of intrauterine growth retardation. Placental EGFR phosphorylation was significantly decreased or absent in 12 cases of small for gestational age neonates, as shown by SDS-PAGE, autoradiography, and scanning analysis. Specific [125I]EGF binding and Scatchard plots of the binding data showed a decreased number of EGFR in 6 of the 12 cases, with a mean maximal binding capacity of 1.09 +/- 0.32 pmol/mg for high affinity sites (mean control value = 2.30 +/- 0.23 pmol/mg). Most of the hypertensive women and smokers belonged to this subgroup. In three of the remaining six cases of small gestational age placentas with low EGFR phosphorylation, there was no maternal pathology or significant parenchymatous placental lesions. Five showed a 175-kD EGFR species when probed by [125I]EGF cross-linking and Western blotting with RK2 and C-Term, two polyclonal anti-EGFR antibodies, suggesting abnormal transduction of the EGF-induced signal. The sixth placenta yielded a single 145-kD EGFR band consistent with an abnormal EGFR structure; Western blot analysis showed no immunoreactive band. In conclusion, maternal and placental pathologies in intrauterine growth retardation are associated with various alterations of placental EGFR, pointing out the importance of EGFR ligands in the regulatory pathway of placental and fetal growth.

Evaluation of X, Y, 18, and 13/21 alpha satellite DNA probes for interphase cytogenetic analysis of uncultured amniocytes by fluorescence in situ hybridization.

The major aneuploidies diagnosed prenatally involve the autosomes 13, 18, and 21, and sex chromosomes. Fluorescence in situ hybridization (FISH) allows rapid analysis of chromosome copy number in interphase cells. This prospective study evaluated the use of four commercially available centromeric DNA probes (DXZ1, DYZ1, D18Z1, and D13Z1/D21Z1) for direct analysis of uncultured amniocytes. One hundred and sixteen amniotic fluid samples were analysed by FISH and standard cytogenetics. This evaluation demonstrated that FISH with X, Y, and 18 alpha satellite DNA probes could accurately and rapidly detect aneuploidies involving these chromosomes and could be used in any prenatal clinical laboratory. In contrast, the 13/21 alpha satellite DNA probe hybridizing both chromosomes 13 and 21 was unreliable for prenatal diagnosis in uncultured amniocytes.

Environmental exposure to cadmium and human birthweight.

Fetal toxicity of cadmium (Cd) is well documented in rodents. However, little information is available regarding the human fetus. To investigate the effect of low levels of Cd on the human placenta and the consequences on birthweight, we conducted a study of 102 mothers and their newborns in an obstetrical care unit. Placental and hair samples were collected at delivery to determine Cd concentrations. The main finding of this study was the relationship between a decrease in birthweight and an increase of newborn hair Cd which varied in the presence of placental calcification. In cases of parenchymal calcifications, placental Cd levels were higher (Wilcoxon test, P < 0.05) and newborn hair Cd levels were lower (Wilcoxon test, P < 0.01) than in the absence of calcification. These relationships remained significant even after taking into account smoking habits and gestational age. In the presence of calcification, an increase in the level of Cd in newborn hair was related to a decrease in birthweight which was independent of placental Cd concentration (rpartial = -0.49, P < 0.01). In the absence of calcification, a decrease in birthweight was observed for the upper values of newborn hair Cd (r = -0.44, P < 0.05 when Cd > or = 0.3 ppm). The difference in birthweight between infants in the first and last quartiles of newborn hair Cd was 472 g in cases of calcifications and 122 g in the absence of calcification. Other placental parameters were not significantly related to placental Cd concentration.