Amniocentesis was performed at 17.3 weeks in a pregnancy with severe intrauterine growth retardation. Cytogenetic studies on amniocytes were normal, 46,XX, and the pregnancy was continued. The diagnosis of Smith-Lemli-Opitz syndrome was suspected in the neonatal period and confirmed by the presence of 7-dehydrocholesterol (7-DHC) in the plasma (0.4 mmol/l, normal = not detectable) associated with a low total cholesterol concentration (0.4 mmol/l, normal = 2.56 +/- 0.23). Retrospective analysis of the amniotic fluid sample revealed an elevated level of 7-DHC (0.022 mmol/l; normal = undetectable). Therefore measurement of 7-DHC levels in amniotic fluid during the second trimester of pregnancy is useful for the prenatal diagnosis of Smith-Lemli-Opitz syndrome in families at risk and should be considered in cases of severe growth retardation of unknown aetiology for which amniotic fluid is available and in which a normal chromosomal pattern in amniocytes is present.
During a follow-up study of 19,790 pregnancies at risk for a genetic disease, from 1968 to 1989, 1083 fetuses were found to have an anomaly during the second trimester, leading to 977 terminations of pregnancy. Neural tube defects (31.4 per cent), chromosomal disorders (27.1 per cent), and Mendelian or multifactorial diseases (10.6 per cent) were the main causes of fetal anomaly. More than half (52.9 per cent) of the fetal anomalies were detected by routine ultrasound examination. Forty-two per cent of cystic hygromas were secondary to a chromosomal defect. We stress the importance of a comprehensive fetal and newborn examination to ensure an accurate diagnosis so that subsequently accurate counselling can be provided.
α-Glucosidase, β-glucosidase and β-galactosidase were studied in cell-free amniotic fluid samples using corresponding 4-methylumbelliferyl-glycosides and a series of disaccharides (maltose, sucrose, trehalose, turanose, cellobiose, gentiobiose and lactose) as substrates. The glycosidases exhibited several properties of intestinal disaccharidases such as pH optimum between 5.2 and 6.4, more activity towards the disaccharides than the artificial substrates, tight association of the activities with sedimentable complexes and β-glucosidase and β-galactosidase activities exerted by a single catalytic site. With the disaccharides as substrates, the amniotic fluid glycosidase activities were well correlated to those reported in the literature for fetal intestine of corresponding gestational ages. The presence of intestinal disaccharidases in amniotic fluid indicates that the fetal intestine contributes to the protein and enzymes of amniotic fluid.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.