ABSTRACT
A method for the isolation and trypsin-Giemsa banding of metaphases obtained after short-term incubation (48 h) of cytotrophoblast cells from chorionic villus sample is described. A new slide-making instrument, developed expressly to enhance the spreading of chromosomes from metaphases released from small tissue pieces, is responsible for the increase yield of analysable metaphases in this protocol.
Subject(s)
Chorionic Villi , Karyotyping/methods , Chromosome Banding/methods , Female , Humans , PregnancyABSTRACT
Fetal chromosome analysis in a twin pregnancy during the first trimester is described. Problems of the reliability of tissue sampling are also discussed. The authors emphasise the advantage of direct cytogenetic analysis from the tissue specimens used for enzyme determination or DNA studies.
Subject(s)
Pregnancy, Multiple , Prenatal Diagnosis , Female , Humans , Karyotyping , Male , Pregnancy , Pregnancy Trimester, First , Twins, DizygoticABSTRACT
The results of the diagnostic application of first trimester trophoblast sampling in 100 pregnancies are reported in detail. Further improvement of the method for routine, direct chromosome analysis resulted in a technique which proved to be fast, simple, and efficient. We found that short-term incubation of villi permits the application of many experimental methods, such as visualization of sister chromatid exchanges and bromodeoxyuridine (BrdU) incorporation. Fetal karyotyping was successful in each of the 96 pregnancies in which fetal material was obtained from a total of 98 fetuses. There were 42 males and 56 females, and an abnormal chromosome constitution was found in 12 cases. Two trisomic fetuses were found among the eight pregnancies at risk for Duchenne muscular dystrophy, and this indicates that fetal sexing (which is achieved with our method in two hours) should not be performed without chromosome visualization. The results indicate a risk of 8% of an abnormal fetus for mothers aged 35 years or more, while the risk of failure of sampling and of spontaneous abortion after villi sampling were 4 and 6%, respectively. Enzyme determinations were performed in three pregnancies at risk for gangliosidosis GM1, Niemann-Pick disease, and Hurler syndrome. In this last case inconsistency between the results of the assay of iduronidase on chorionic villi and amniotic fluid cells was found. This unexplained error indicates the need for extensive characterisation in chorionic villi of the series of enzymes involved in metabolic diseases.
Subject(s)
Chorionic Villi/ultrastructure , Chromosome Aberrations , Placenta/ultrastructure , Prenatal Diagnosis/methods , Trophoblasts/ultrastructure , Adult , Chromosomes, Human, 13-15 , Chromosomes, Human, 16-18 , Clinical Enzyme Tests , Female , G(M1) Ganglioside , Gangliosidoses/diagnosis , Humans , Karyotyping , Male , Maternal Age , Niemann-Pick Diseases/diagnosis , Pregnancy , Pregnancy Trimester, First , Pregnancy, High-RiskABSTRACT
Chorionic villi were obtained by an aspiration technique which proved to be the best of four alternative procedures. We report in detail the series of experiments which led to (1) successful, rapidly growing cell cultures practically free of maternal cell contamination (the use of hormone-supplemented Chang medium greatly increased the growth rate); (2) an efficient direct method to obtain high quality metaphases from the Langhans cells of the cytotrophoblast tissue and with which the fetal karyotype is defined within a few hours of chorionic villi sampling; and (3) successful testing for the activity of eight enzymes directly from the villi samples, thus showing that this material is suitable for a rapid, direct diagnosis of the related metabolic diseases.
Subject(s)
Chorionic Villi/ultrastructure , Karyotyping/methods , Placenta/ultrastructure , Prenatal Diagnosis/methods , Catheterization/methods , Chorionic Villi/enzymology , Culture Techniques , Endoscopy , Female , Fetus/ultrastructure , Humans , Pregnancy , Pregnancy Trimester, First , Specimen Handling , Suction , Ultrasonography , UterusABSTRACT
The development of prenatal diagnosis in Italy was made difficult by the restrictions of the old abortion law and only in recent years has a consistent number of cases been investigated. We report the experience on prenatal chromosome diagnosis of ten Italian centers participating in a collaborative study on 4952 diagnoses performed from 1972 to 1980. The main indication groups were: advanced maternal age (2882 cases), previous child with chromosome anomaly from parents with normal karyotype (847 cases), and chromosome anomaly in one parent (97 cases). The other indications for amniocentesis, including cases without a cytogenetic risk, have been assembled into a "miscellaneous" group (1126 cases). We found 125 abnormal fetal karyotypes (2.5%) of which 89 were unbalanced (1.8%). The frequencies and types of chromosome anomalies are reported in detail for each indication group and are compared with the corresponding one from the European Munich Conference. The great majority of these Italian data were not included in the Munich report.
Subject(s)
Prenatal Diagnosis , Chromosome Aberrations/diagnosis , Chromosome Disorders , Female , Humans , Italy , Karyotyping , Male , Maternal Age , Pregnancy , RiskSubject(s)
Abortion, Habitual/genetics , Chromosome Inversion , Chromosomes, Human, 6-12 and X , Chromosome Banding , Female , Humans , Male , PregnancyABSTRACT
A 19 years old girl with gonadal dysgenesis and short stature had one giant chromosome formed by two X-chromosomes attached by their short arms 46,X,i dic(X) (p223::p223) A 45,X cell line was present in 40% of cultured lymphocytes but only in 2% of fibroblasts cultured from the right gonad and absent in fibroblasts from the left gonad and skin. The abnormal chromosome had one Cd-positive, active centromere and one inactive centromere. A study of DNA replication with autoradiography and BrdU treatment revealed that the abnormal X was always the late replicating one. In a proportion of cells there was an asymmetric pattern of replication : the region with the inactive centromere had a tendency to replicate later than the portion with the functioning centromere. The Xg blood group segregation suggested that the attached X chromosomes were of paternal origin and therefore a true isodicentric formed after an isochromatid break followed by joining of the two sister chromatids.
Subject(s)
Centromere , Chromosomes , Gonadal Dysgenesis/genetics , Sex Chromosome Aberrations/genetics , Adolescent , DNA Replication , Female , Humans , X ChromosomeABSTRACT
A marriage between two first cousins who have the same 2/7 balanced translocation is reported. The chromosome rearrangement was primarily detected in amniotic fluid cells cultured for prenatal chromosome analysis because of advanced maternal age. The translocation was also found in the couple's two normal children and in three other members of the family. The possible zygotic chromosome constitutions following 2:2 meiotic segregation in consanguineous parents with the same translocation are discussed.
