Practical experience using transabdominal chorionic villus biopsies taken after 16 weeks' gestation for rapid prenatal diagnosis of chromosomal abnormalities

Placental biopsy was performed on 81 patients at greater than 16 weeks' gestation. The major indication for such biopsies was an increased risk of chromosomal abnormality because of either abnormal ultrasound findings or late presentations for advanced maternal age. Six abnormal karyotypes resulting in elective termination were found. The use of rapid karyotyping by this procedure as an alternative to amniocentesis or fetal blood sampling is discussed.     

Amylo-1,6-glucosidase activity in cultured cells: A deficiency in type III glycogenosis with prenatal studies

Deficiency of amylo-1,6–glucosidase activity was expressed in parallel in liver and skin fibroblasts from a patient with type III glycogenosis. In crude extracts of control liver and muscle, amylo-1, 6–glucosidase (M.W. 164000) was identified by immunoprecipitation; no cross-reacting material was found in the patient's liver. Assay of amylo-1,6–glucosidase activity in cultured skin fibroblasts from the affected family revealed less than 10 per cent of control value in mutant homozygous cells whereas in cells from the parents, activity was reduced to 40–60 per cent of the control value. Activity in cultured amniotic fluid cells was similar to that of control fibroblasts. In cultured amniotic fluid cells obtained during the mother's subsequent pregnancy, the normal amylo–1,6–glucosidase activity measured, predicted correctly the outcome of this pregnancy prior to the 20th week of gestation.     

Confined placental mosaicism,IUGR, and adverse pregnancy outcome: A controlled retrospective U.K. collaborative survey

In a retrospective collaborative study involving 21 U.K. laboratories and 11775 CVS prenatal diagnostic procedures, a total of 73 cases of confined placental mosaicism (CPM) were identified among the 8004 first-trimester referrals because of advanced maternal age, a previous child with a numerical chromosome abnormality, or a family history of the same. Data were collected on subsequent cytogenetic follow-up and pregnancy outcome for each case and a referral matched control. Comparison with the control population failed to demonstrate a marked increase in adverse pregnancy outcome in the CPM group, but a significant increase in both low and high birth weight infants was recorded. In a parallel study, 7 out of 108 cases, referred for prenatal diagnosis because of ultrasound detection of isolated intrauterine growth retardation (IUGR) in the second or third trimester, were shown to have a chromosome abnormality restricted to the extraembryonic tissues. These included cases of CPM involving trisomy 9 and del(13)(q13), neither of which has previously been reported in association with IUGR.