[Reduplication behavior of chromosomes of group D (13-15) and identification of the extra-chromosome in trisomy D].
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Biomedical subjects
Publications and source records attributed to R A Pfeiffer.
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In repeat amniotic fluid cultures mosaicism due to trisomy 9 was noted. Autopsy of the aborted female fetus showed a sinus urogenitalis and gonadal dysgenesis with absence of germ cells only. Fetal lymphocytes and skin fibroblasts had a normal karyotype but trisomy 9 was found in cells grown from placenta. It is likely that trisomic cells were limited to fetal membranes.
Chromosomal analysis in a child with ambiguous sex showed mosaicism of at least two cell lines with one or more marker chromosomes or none at all. They were shown to be derived from the Y chromosome by fluorescent in situ hybridisation (FISH) using different DNA probes that cover parts of the long and the short arm.
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BACKGROUND: In the case of abnormal ultrasound findings, abnormal serum-screening and age-risk in advanced pregnancy a rapid diagnosis or exclusion of a chromosomal aneuploidy of the fetus is of great value for the clinical management. With fluorescence in situ hybridization (FISH) on uncultured amniotic fluid cells the detection of the most common aneuploidies, which account for about 2/3 of all chromosomal aberrations [1], is possible within 24 hours. The aim was to evaluate if the FISH-technique in combination with karyotyping after cell culturing could replace other methods like diagnostics form umbilical cord blood or placental biopsies. MATERIALS AND METHODS: For the FISH assays commercially available directly with fluorochromes labelled DNA-probes (Vysis, Stuttgart) were used. FISH assays were performed on amniotic fluid samples from pregnancies at risk for fetal chromosome aberrations parallel to standard cytogenetic analysis. The method was performed on 230 samples of amniotic fluid. We tried to optimize the method concerning preparation of the cell material, the denaturation- and hybridization-steps and well as stringency of post-hybridization washes. RESULTS: All trisomies 13, 18, 21 and the sex chromosome aneuploidies (n = 34) which were diagnosed by conventional cytogenetics were identified correctly by FISH analysis with the exception of one case of trisomy 21 mosaicism, in which hybridization failed. As structural chromosome aberrations and mosaicisms cannot be detected with this method, six additional chromosome aberrations were identified exclusively by cytogenetic analysis. The mean frequency of nuclei with abnormal signal pattern in the aneuploid cases was 89%. A minimum of 50 nuclei for each DNA-probe could be counted in 86% of the samples. The results of 12 cases were classified as uninformative, because only less than 15 hybridized nuclei or no hybridization signals could be scored. Maternal contamination was found in 17.4% of the samples. CONCLUSIONS: In clinical cases with a high risk for an abnormal fetal karyotype and the need of quick clinical consequences, methods which make possible a karyotyping within shortest time should be preferred to amniocentesis and FISH-analysis, because Chromosomal mosaicism and structural aberrations, which represent up to 20% of all chromosomal abnormalities in this group, cannot be detected, uninformative cases can occur in up to 15% of all investigated samples and There is a risk for false-negative results through contamination of the sample with cells of maternal origin. In comparison with methods which permit rapid karyotyping from umbilical cord blood or placental biopsies, a delay in the diagnostic procedure has to be accepted, when the result of the FISH-analysis has to be confirmed by cell culturing and standard cytogenetic analysis.
We report on two patients who exhibit the typical features of the rare Zimmermann-Laband syndrome such as gingival fibromatosis, swelling of perioral tissues, nail hypo/aplasia, and abnormalities of terminal phalanges. The older patient suffers from epileptic seizures and shows osseous mandibular hypertrophy, two maxillary mesiodentes and lumbar spondylodysplasia. In the 2nd patient, a 3 year old male, the characteristic morphological features are already present.
Report on a 3 year old female with mild dysmorphies, moderate developmental retardation and dysplasias of multiple thoracic vertebrae. These features are related to an additional isochromosome of the long arm of an X chromosome. The phenotype is difficult to understand if the additional genetic material would be inactivated totally as shown by late replication. In the literature only two similar cases are recorded.
Report on two males who exhibit a syndrome which reminds Prader-Willi-Labhart syndrome (PWLS) because of craniofacial dysmorphy, acromicria, hypogenitalism, obesity and mental deficiency. A supernumerary small marker chromosome was identified as duplication of the juxtameric parts of chromosome 15. In a 15 years old female and in a 4 years old unrelated male deletion of 15q1 is due to translocation with a chromosome 7 and 20 respectively subsequent to 3:1 distribution. Therefore both patients share partial monosomies of chromosome 15 but also of the other autosome involved. Various chromosomal aberrations in PWLS but mostly deletions of chromosome 15 either isolated or associated with translocation are summarized. Patients with a PWLS like syndrome and a marker chromosome consisting of juxtameric parts of chromosome 15 constitute a particular group which is delineated from PWLS but also from a large heterogeneous group of supernumerary marker chromosomes.
A five year old boy is reported with typical signs of Trisomy 8-Syndrome: long, narrow face, broad based nose, eversion of lower lip, microgeny, dysplastic ears, deep palmar and plantar furrows, scoliosis, and only mild retardation. The karyotype in 150 lymphocytes was normal. In fibroblast culture mosaicism was found: 46,XY/47,XY,+8.
We report on the prenatal diagnosis of bilateral fetal cataract in the 17th week of pregnancy as the first ultrasonographic sign of a Walker-Warburg syndrome in a familial case. No other anomalies could be detected by ultrasonographic examination at that time. Both the bilateral fetal cataract and specific abnormalities of a Walker-Warburg syndrome were confirmed after the termination of the pregnancy in the second trimester.