Biomedical subjects

N Collot

Publications and source records attributed to N Collot.

4 recordsLinked to original sources

PubMed2000

Analysis of uncultured amniocytes by comparative genomic hybridization: a prospective prenatal study.

Comparative genomic hybridization (CGH) is a new molecular cytogenetic technique which can detect and map whole and partial aneuploidies throughout a genomic specimen DNA without culturing specimen cells. Thus, CGH may be used as a comprehensive and rapid screening test in prenatal unbalanced chromosomal abnormalities detection. We report the results of the first prospective study to evaluate the use of the CGH technique on uncultured amniocytes. Seventy-one amniotic fluid samples, obtained by transabdominal amniocentesis between the 14th and 35th weeks of gestation, were simultaneously investigated using CGH and conventional cytogenetics. Amniocentesis were done for advanced maternal age (21.1%), fetal ultrasound anomalies (73.3%) and high level of biochemical markers in maternal serum (5.6%). Sixty-six (93%) informative results were generated on a total of 71 analysed specimens. Fifty-nine samples were reported as disomic for all autosomes with a normal sex chromosome constitution using CGH and conventional cytogenetics. Among them, three pericentromeric chromosomal inversions were undetected by CGH analysis. Seven numerical aberrations were characterized, including one case of trisomy 13, one case of trisomy 18 and five cases of trisomy 21. Advantages and limitations of CGH for a rapid prenatal screening of unbalanced chromosomal aberrations are discussed.

Amniocentesis↗

PubMed1999

De novo inverted duplication 9p21pter involving telomeric repeated sequences.

We report on clinical and cytogenetic findings in a boy with partial 9p duplication, dup(9)(p21pter). Clinical manifestations included facial and hand anomalies and mental retardation. Fluorescence in situ hybridization (FISH) and comparative genomic hybridization (CGH) were used to characterize further and confirm the conventional banding data. Investigation by FISH using whole chromosome 9 paint probe showed that the additional material was derived from chromosome 9. Using CGH, a region of gain was found in the chromosome segment 9p21pter. YACs and telomeric probes confirmed the duplicated region. Using the all-human telomeric sequences probe, intrachromosomal telomeric signal was noted on the short arm of the abnormal chromosome 9. Mechanism of formation of the duplication, including intrachromosomal telomeric sequences, is discussed.

Abnormalities, Multiple↗

PubMed1998

Comparative genomic hybridization: technical development and cytogenetic aspects for routine use in clinical laboratories.

Comparative genomic hybridization (CGH) offers a new global approach for detection of chromosomal material imbalances of the entire genome in a single experiment without cell culture. In this paper, we discuss the technical development and the cytogenetic aspects of CGH in a clinical laboratory. Based only on the visual inspection of CGH metaphase spreads, the correct identification of numerical and structural anomalies are reported. No commercial image analysis software was required in these experiments. We have demonstrated that this new technology can be set up easily for routine use in a clinical cytogenetics laboratory.

Aneuploidy↗

PubMed1998

Comparison of comparative genomic hybridization with conventional karyotype and classical fluorescence in situ hybridization for prenatal and postnatal diagnosis of unbalanced chromosome abnormalities.

The comparative genomic hybridization (CGH) technique was initially used for detection of chromosomal imbalances in tumor cells. CGH can also be used as a supplementary method to karyotypic analysis in clinical cytogenetic cases. In order to evaluate CGH usefulness in prenatal and postnatal analysis of whole chromosome and segmental aneusomies, we investigated 13 clinical samples from blood, cultured chorionic villi, cultured amniotic fluids and uncultured amniotic fluids. These specimens, initially analyzed by conventional cytogenetics, included 5p monosomy, 9p duplication, add 6p, unbalanced translocation between chromosomes 5 and 10, mosaic tetrasomy 12p (50%), unbalanced (X;X) translocation and Prader-Willi deletion (15q11-13). In addition, six numerical chromosome aberrations (tetrasomy X, trisomies 13, 18, 21 and monosomy X) were analysed. All the chromosomal abnormalities, except the Prader-Willi deletion, were correctly detected by CGH. Here, we have demonstrated that the CGH technique is an alternative to classical fluorescence in situ hybridization using specific probes for detection of the unbalanced chromosomal aberrations in prenatal and postnatal diagnosis and could be used for rapid prenatal screening for unbalanced aberrations.

Amniotic Fluid↗