Two years' prospective experience using fluorescence in situ hybridization on uncultured amniotic fluid cells for rapid prenatal diagnosis of common chromosomal aneuploidies.

A probe was generated from the YAC clone 831B9 that was suitable for the prenatal detection of trisomy 21 using fluorescence in situ hybridization (FISH). This probe was initially tested on a series of 650 unselected amniotic fluid samples prior to the karyotype being available. 630 were correctly identified as having two copies and 13 samples were correctly scored as having three copies of chromosome 21. Seven samples failed to produce a result. A trial was then initiated, reporting to clinicians the interphase FISH results before cytogenetic analysis had been performed. During the first 18 months of this trial 1504 samples were tested: 1467 were correctly identified as disomic and 35 samples were correctly scored as trisomic for chromosome 21. Two samples failed to produce a result. A chromosome 18 specific probe (LI.84) was employed where there was a relevant clinical indication (181 samples) and 10 samples were correctly scored as having three copies of chromosome 18. Thus, this approach appears to be reliable and is popular with both clinicians and patients due to the speed of the result. However, it does not replace chromosomal analysis on cultured cells, which detected a range of abnormalities besides the trisomies and triploidies detected by FISH.

Prenatal diagnosis in the United Kingdom--an overview.

Prenatal diagnosis is now a well-established part of health care in the UK. Cytogenetic or molecular diagnostic analysis following amniocentesis, chorionic villus sampling or cordocentesis is in routine practice and identification of 'at risk' pregnancies using biochemical screening or ultrasound is widespread. Professional guidelines have been established covering both sampling procedures and diagnostic testing, and legislation is in place regarding termination of pregnancy and pre-implantation diagnosis. The close liaison of the various groups of professionals involved has led to well-developed prenatal diagnostic and screening services within the UK. These links have been the major contributory factor to the current state of prenatal diagnosis and have been of great benefit to patients undergoing prenatal testing.

Long-term culture of primary breast cancer in defined medium.

Over a period of 6 1/2 years between January 1986 and May 1992, 135 unselected primary breast cancers were cultured and of these 10 developed into cell lines. Six of the lines grew in defined serum-free medium, while the other four required supplementation with 0.5% fetal calf serum. Two of the lines are from the same breast, being derived from a local excision specimen and from a mastectomy specimen 12 months later. In addition, 12 lymph nodes containing metastatic breast cancer were cultured; one of these cultures became permanent in a defined serum-free medium. Oestrogen receptor (ER) status was negative in all but one of the tumours which grew successfully, and even in this case the derived cell line is ER negative. The epithelial nature of the lines has been confirmed by immunocytochemistry and by electron microscopy (EM), while their malignant nature is shown by morphology, unattached growth, chromosome analysis, and, in the case of the line from a lymph node metastasis, the absence of any benign source of epithelial cells.

Congenital ocular defects associated with an abnormality of the human chromosome 1: trisomy 1q32-qter.

This article describes the detailed ocular pathology found in a premature neonate, born at 34 weeks, with multiple congenital anomalies resulting from de novo trisomy 1q32-qter. The ocular defects include goniodysgenesis, persistent tunica vasculosa lentis and hyaloid vessels, hypopigmentation of the posterior iris epithelium, ectopia of the ciliary processes, and abnormal insertion of the ciliary muscle and cataract. This is the first report of the detailed ocular pathology in a case of trisomy 1q and is also unusual in that the chromosomal defect has apparently arisen de novo in the proband.

Second-trimester placental biopsy for rapid fetal karyotyping.

Since January 1988 the technique of first-trimester chorionic villus sampling (placental biopsy) has been extended to include cases in the second trimester. To date, 40 procedures have been performed. The main indication for the late chorionic villus sampling was a low serum alpha-fetoprotein value in association with an increased risk for Down syndrome (n = 28), abnormal ultrasonographic finding (n = 7), and failed amniotic cell culture (n = 3). Successful karyotype results were achieved in all but two cases. Most results were obtained within 48 hours with direct cytogenetic techniques. No cases of mosaicism were found. The highest yield of abnormal karyotypes was obtained from the cases with abnormal ultrasonographic findings (one trisomy 21, two 45,X). One case of trisomy 21 was identified in the 28 cases of low serum alpha-fetoprotein. No spontaneous losses have occurred. The technique is easy to learn, does not differ from first-trimester procedures, and may have a lower complication rate than cordocentesis. The reporting of cases to the CVS Newsletter should help evaluate late chorionic villus sampling as another method for rapid fetal karyotyping.

Prenatal diagnosis of medium-chain acyl-coenzyme A dehydrogenase deficiency.

A fatal case of medium-chain acyl-coenzyme A dehydrogenase deficiency is described in a patient who presented with hypoglycaemia and a gross non-ketotic dicarboxylic aciduria. Cultured skin fibroblasts released 14CO2 from [1-14C] octanoic acid at half the normal rate. Prenatal diagnosis was undertaken in a subsequent pregnancy in which cultured amniotic fluid cells revealed a marked reduction in octanoate oxidation indicative of an affected fetus. The pregnancy was terminated and the diagnosis was confirmed by enzyme analysis of skin fibroblasts taken from the fetus. The high residual octanoate oxidation by affected fibroblasts together with the absence of any characteristic abnormality of amniotic fluid organic acids are a potential limitation to the reliability of this type of prenatal diagnosis.

Non-random chromosome changes in a herpes-virus-transformed Syrian hamster cell line and its metastatic derivatives.

A primary subcutaneous tumour of low spontaneous metastatic capacity, produced after inoculation of Herpes-virus hominis type-2-transformed hamster fibroblasts (parent line) and two in vivo derived highly metastatic lung deposits (Met A and Met B) were karyotyped and compared after trypsin G-banding. The parent line was cytogenetically heterogeneous with a modal chromosome number of 74. However, a number of cells were of a higher ploidy level. A large variation in both numerical and structural abnormalities was observed, the chromosome rearrangements were often complex and unstable, but all the cells contained a theme of common marker chromosomes. Met A and Met B were near diploid (mean chromosome numbers 42 and 44 respectively) with a low level of tetraploid cells. They shared many chromosome rearrangements but could be readily distinguished by an additional translocation unique to Met A. Cytogenetic homogeneity within and between metastases suggested that they were of monoclonal origin and had been derived from a karyotypically similar subpopulation within the parent tumour. We were unable to detect such cells in the parent line; thus, their numbers within the parent tumour were likely to be low. Metastasis, therefore, has been highly selective, depending on the particular phenotypic properties of Met A and Met B. All cells of the parent and metastatic lines have homogeneously staining regions (HSR) and abnormalities of chromosomes 15 (C15) which may be important in tumorigenesis. In addition, Met A and Met B cells have a number of chromosome rearrangements [translocations, deletions and a double minute chromosome (DM)] not present in the parent cells. They are retained at a high frequency in the cells of Met A and Met B and thus it seems likely that the metastatic phenotype is associated with one or more of these chromosome aberrations.