Foamy changes of placental cells in fetal storage disorders

Mucolipidosis Type II Affecting 1 Fetus and Placental Disk of a Dichorionic-Diamnionic Twin Gestation: A Case Report and Review of the Literature

Mucolipidosis type II, also known as I-cell disease, is an autosomal recessive inborn error of metabolism, resulting from loss-of-function mutations in GNPTAB. Affected infants exhibit multiple physical anomalies and developmental delay, and death from disease follows in early childhood. Here we present an instructive case of mucolipidosis type II affecting 1 fetus and placental disk in a dichorionic-diamnionic twin pregnancy delivered at 36-wk gestation. The second twin and placental disk showed no abnormality. On microscopic examination, the affected placenta displayed marked vacuolization of the syncytiotrophoblast and Hofbauer cells, which was confirmed on ultrastructural examination. To our knowledge, this is the first description of placental findings in a twin pregnancy, wherein only 1 twin is affected by an inborn error of metabolism. This provides an opportunity to highlight the placental abnormalities seen in this group of diseases, and to emphasize the role of pathologic examination in early detection of otherwise unsuspected inborn errors of metabolism.

Prenatal mucolipidosis type II (I-cell disease) can present as Pacman dysplasia

Pacman dysplasia has been previously reported to be a lethal skeletal dysplasia with epiphyseal stippling and osteoclastic overactivity. We report on a sibling of a fetus previously reported as Pacman dysplasia. This infant has a clinical course consistent with mucolipidosis type II (I-cell disease) along with confirmatory biochemical, cytologic, and radiographic evidence. This case expands the phenotypic spectrum of mucolipidosis type II. Having redefined the diagnosis in one of the original cases of Pacman dysplasia, we suggest that what is called Pacman dysplasia could very well be Mucolipidosis type II (ML-II) in other published reports.

Identification of Gaucher cells in the chorionic villi associated with recurrent hydrops fetalis

Recurrent non-immune hydrops fetalis has rarely been reported. In order to detect the risk of recurrence in a subsequent pregnancy, one should carefully consider the possibility of an inborn error of metabolism. In such cases, placental examination may be useful in detecting such metabolic storage disorders in the fetus, which usually present as vacuolization of placental cells. We describe a rare case of recurrent hydrops that was detected by placental examination. Through light microscopy, electron microscope (EM) studies and beta-glucocerebrosidase activity the disease was identified as Gaucher's disease.

Prenatal diagnosis of lysosomal storage diseases

The prenatal diagnosis of lysosomal storage disorders can be achieved, once the diagnosis is confirmed in the index case, by a variety of techniques including analysis of amniotic fluid, asay of enzymic activity in cultured amniotic fluid cells, cultured chorionic villus cells and by direct assay of activity in chorionic villus samples. These studies can be accompanied by ultrastructural observations which give an independent means of diagnosis. In some instances molecular genetic studies for mutation detection or linkage analysis are appropriate for prenatal diagnosis. Pseudodeficiencies of some of the lysosomal enzymes, which cause no clinical problems, can complicate the initial diagnosis particularly in metachromatic leucodystrophy where the pseudodeficiency is more common than the disease itself. Mutation analysis as well as enzyme assay is necessary not only in the index case but also in the parents before the same techniques are applied to a sample for prenatal diagnosis. A large number of lysosomal storage disorders may present as fetal hydrops and the diagnosis can be established at this late stage by fetal blood sampling and examination by microscopy as well as by biochemical assay of the appropriate enzyme or metabolite in amniotic fluid. All prenatal diagnoses in which an affected fetus is indicated should have confirmation of the diagnosis as soon as possible to reassure anxious parents, and to act as audit of the laboratory's competence to undertake prenatal diagnosis. A combined approach to prenatal diagnosis involving biochemical, molecular genetic and morphological studies is recommended.

Foamy changes of placental cells in probable beta glucuronidase deficiency associated with hydrops fetalis

Mucopolysaccharidosis type VII (MPS VII, beta glucuronidase deficiency) has been described in association with non-immune hydrops fetalis. Three consecutive pregnancies in an itinerant family, which resulted in stillbirths caused by non-immune hydrops are described. The parents were closely related and there was a strong family history of storage disorders. The main clue to the diagnosis, however, came from the presence of pronounced foamy cytoplasmic change in the villous Hofbauer cells of the placenta. This raised the possibility of an inherited metabolic storage disorder. The parents were subsequently shown to have beta glucuronidase activities in the heterozygous range in leucocytes and fibroblasts which suggested that the non-immune hydrops was caused by beta glucuronidase deficiency.

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 beta-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.

Diagnosis of unsuspected fetal metabolic storage disease by routine placental examination

GM1 gangliosidosis (type 1) is a rare hereditary, autosomal recessive, lysosomal storage disease characterized by a marked deficiency of active acid beta-galactosidase resulting in accumulation of gangliosides and mucopolysaccharides in tissues. Disease status of newborns from affected kindreds may be diagnosed by placental examination. Typical findings include a characteristic vacuolar distension of the cytoplasm of syncytiotrophoblast and stromal Hofbauer cells. We report a case of unsuspected fetal storage disorder initially diagnosed by routine placental examination of a normal-appearing infant born to a previously unaffected family. Progressive, third-trimester oligohydramnios and fetal growth retardation had been documented by ultrasonography. Placental findings included vacuolization of syncytiotrophoblast, intermediate trophoblast, and stromal Hofbauer cells. Subsequent enzyme analysis confirmed the placental findings of storage disorder and diagnosed GM1 gangliosidosis.

Ultrastructure of the human placenta in metabolic storage disease

Eleven placentae and one fibroblast cell culture from pregnancies complicated by various inherited metabolic disorders, together with five chorionic villus biopsies from pregnancies at risk, were examined for ultrastructural evidence of accumulation of metabolites. Abnormal ultrastructural features were present as early as 10 weeks gestation. Myelin bodies were found in all placental cell types in a case of Niemann-Pick disorder and stromal cells showed marked vacuolation in Hurler's disease. Membranous arrays were occasionally identified in the lysosomes of stromal cells in a case of Sandhoff's disease, together with some myelin body formation in the trophoblast and endothelium. In Pompe's disease, intralysosomal accumulations of glycogen were present in all cell types except syncytiotrophoblast, while in sialic acid storage disorder all placental cells were affected except for the cytotrophoblast. Collagen fibre disorientation and excess associated proteoglycan was seen in a formalin-fixed placenta with Sanfilippo mucopolysaccharidosis, and syncytial vacuolation, caused possibly by delays in fixation, was evident in many specimens. The specimens were collected from different centres and the fixation procedure varied significantly. The most satisfactory results were obtained from chorionic villus sampling in vivo and from pregnancies terminated using aspiration followed by immediate fixation. The importance of liaison with clinicians is stressed in order to obtain optimal preservation of the tissue. This is particularly vital in immature specimens of placenta where abnormal storage product material may not have had time to accumulate.

Placental pathology and prenatal diagnosis of infantile type of neuronal ceroid-lipofuscinosis

Five term placentae from pregnancies at risk of infantile neuronal ceroid-lipofuscinosis (INCL) were studied electron-microscopically to determine if diagnostic cytoplasmic inclusions could be detected in this tissue. In 4 placentae no inclusions were found, and the infants born from these pregnancies have developed normally, the shortest observation time being 15 months. In the fifth placenta numerous cytosomes pathognomonic of INCL were found in the amniotic cells and the endothelium of the capillaries of the chorionic villi. The diagnostic significance of this finding was confirmed by the presence of typical inclusions in the autonomic ganglion cells and other cells in a rectal mucosal biopsy specimen of this male infant at the age of 3 months. Electron microscopic study of chorionic villus biopsy specimens appears to be a promising possibility for prenatal diagnosis of INCL.

Placental electron microscopy and histochemistry in a case of sialic acid storage disorder

Morphological alterations in a placenta from a case of infantile sialic acid storage disease are described. Syncytiotrophoblast, villous capillary endothelial cells, amniotic and Hofbaüer cells were filled with membrane-bound inclusions which were either electron-lucent or contained fibrillogranular material. Hydrolysis of slides with neuraminidase demonstrated at six hours Alcian blue material which was not present in normal syncytium. The possibility that a storage disorder such as sialic acid storage disease can be accurately diagnosed by electron microscopy on chorion villous sampling at nine to ten weeks is emphasized.

Morphologic characteristics of the placenta in glycogen storage disease type II (alpha-1,4-glucosidase deficiency)

Five placentas from infants with enzymatically diagnosed glycogen storage disease type II (three from midtrimester abortions, two from term deliveries) were studied by light and electron microscopy. On routine histologic examination with hematoxylin and eosin staining, storage cells were identifiable in the connective tissue of the amnion. These cells provide the means to diagnose this glycogen storage disease prior to the development of clinical symptoms. Electron microscopy, even in the midtrimester placenta, shows typical membrane-bound, glycogen-filled vacuoles in the villous endothelium and stromal cells. These vacuoles can provide confirmation of glycogen storage in cases of prenatal enzymatic diagnosis and therapeutic abortion.

Placental ultrasonographic biochemical and histochemical studies in human fetuses affected with Niemann-Pick disease type A

Placental ultrasonographic, bio- and histochemical studies were performed on four unrelated fetuses affected with Niemann-Pick disease Type A, following prostaglandin-induced abortion at about the 19th week of gestation. An accumulation of sphingomyelin in the placentae of affected fetuses indicates the essential role of the enzyme sphingomyelinase, even during the early stages of gestation. A fair correlation between histochemical localization of sphingomyelin in the placentae and ultrasonographic findings was found, indicating the value of ultrasonic echo wave information in the diagnosis of metabolic disorders.

Prenatal diagnosis and fetal pathology of aspartylglucosaminuria

The prenatal diagnosis of aspartylglucosaminuria (AGU), a lysosomal storage disorder of glycoprotein degradation, was made by demonstrating the deficiency of N-aspartylglucosaminidase on cultured cells from a midterm amniotic fluid sample. Four other amniotic fluid studies from at-risk pregnancies gave a normal or a heterozygote level of enzyme activity. These pregnancies have gone to term and the delivery of healthy babies. The pregnancy with the affected fetus was terminated and the prenatal diagnosis was verified by enzyme assays on cord blood lymphocytes, cultured cells from skin biopsy, and from placental villi. Electron microscopic evidence of lysosomal storage was seen in several organs of the fetus with the notable exception of the central nervous system. The undifferentiated mesenchymal fibroblasts particularly were heavily loaded with cytoplasmic inclusions in skin, liver, kidney, and placenta.

The ultrastructural demonstration of placental phospholipids in preterm, term and eclamptic pregnancies

Using a technique for the retention and visualization of aqueously soluble phospholipids the localization of phospholipids has been studied in placentae from preterm, term, and eclamptic pregnancies. Phospholipid accumulations at 32 weeks appear solely in the syncytiotrophoblast but as gestation increases phospholipids are found in an increased number of tissue compartments. By term, granules are seen in syncytiotrophoblast, cytotrophoblast, capillary endothelium, and the subtrophoblastic stroma. Two placentae from eclamptic pregnancies at 32-weeks demonstrate phospholipid localizations very similar to those found in the normal placenta at term. Additional non-straining lipid inclusions are seen within vascular pericytes in placentae from patients with eclampsia. The findings observed in the 32-week placentae from eclamptic pregnancies may be due to accelerated phospholipid metabolism, synthesis, or storage.

Foamy degeneration of placenta

A case of striking foamy transformation of placental and stromal decidual cells is reported. These findings are similar to those described in the placenta of infants affected by fetal storage disorders. However, in our case a very critical study allowed us to conclude that these changes were non-specific and regressive. They were presumed to be concomitant with fetal death or possibly secondary to oedema or anoxia. This case is reported to demonstrate how difficult the differential diagnosis of the appearance of the placenta in fetal storage disorders may be.

A morphometric study of placenta in fetal congenital nephrotic syndrome of Finnish type

A qualitative light microscopic study was performed on 9 fetal congenital nephrotic (CNF) and 13 control placentas obtained from legal pregnancy terminations or spontaneous abortions at 16-20 weeks of gestation. From this material 6 CNF cases and 6 age matched controls were selected for morphometric analysis. The total villous volume and the ramification pattern of the villi were similar in CNF and controls. A significant decrease in the villous vascularization was found in CNF. It is suggested that disturbed oxygen exchange due to poor development of the villous vessels causes a compensatory hyperplasia of the placenta at birth in CNF. Electron microscopic investigation was performed on three CNF and two control placentas. No changes typical of fetal CNF were found in the villous ultrastructure. The syncytial microvillous projections seemed to be more numerous and longer in CNF, otherwise the structure of the trophoblastic layer of the villi and the lining of the subtrophoblastic vessels were identical in CNF and controls.

Morphology of the placenta in fetal I-cell disease

Placentas were studied from three interrupted pregnancies of a mother whose first liveborn child had I-cell disease (mucolipidosis II). I-cell disease of the fetus was shown by investigation of the amniotic fluid, fetal cells and the aborted fetus in two pregnancies, but in the third case placenta was the only available product of conception. In every placenta extensive vacuolization of the syncytiotrophoblastic layer of the chorionic villi and chorionic mesenchymal cells was found. In electron microscopy the inclusions were identical to those of other tissues in I-cell disease. The importance of histological study of placenta in unexplained spontaneous abortions needs to be emphasized, since this may be the only way of detecing new cases of lysosomal storage diseases.