Karyotyping
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Cíl studie: Posunutí indikovaného invazivního vyšetření v prenatální diagnostice do ranějšíchfází gravidity při současném zachování výpovědní hodnoty cytogenetického nálezu.Typ studie: Cytogenetická a molekulárně-cytogenetická analýza choriových klků po dlouhodobékultivaci.Název a sídlo pracoviště: Ústav lékařské genetiky a fetální medicíny, LF UP Olomouc, FN Olo-mouc.Metodika: Kultivace buněk pocházejících z choriových klků po enzymatické nebo mechanickédisociaci a jejich karyotypizace. Využití fluorescenční in situ hybridizace k vyloučení nejčas-tějších chromozomálních aneuploidií a ke stanovení gonozomů v indikovaných případech.Výsledky: Testování a optimalizace metody dlouhodobé kultivace k rutinnímu využití. Metodabyla použita doposud na 12 případech s úspěšností 83 %. V 6 případech byla karyotypizace doplně-na o fluorescenční in situ hybridizaci.Závěr: Využití metody dlouhodobé kultivace choriových klků jako rutinního postupu prenatálnídiagnostiky.
Objective: Shift of indicated invasive examination in prenatal diagnostics towards the earlierphases of pregnancy with preservation of quality of cytogenetic detection.Design: Cytogenetic and molecular-cytogenetic analysis of the chorionic villi after long termculture.Setting: Department of Medical Genetics and Foetal Medicine, Faculty of Medicine, Palacky Uni-versity Olomouc, Faculty Hospital in Olomouc.Methods: Cultivation of fibroblasts developing from chorionic villi after enzymatic or mechanicaldisintegration and their karyotyping. Using fluorescent in situ hybridisation to identify the mostcommon chromosomal aneuploidies and to determine gonosomes in indicated cases.Results: Testing and optimisation of long term culture method and its routine use. Method wasutilised so far in 12 patients and successfulness was 83 %. Additional fluorescent in situ hybridisa-tion was performed in 6 cases.Conclusion: Using long term culture method of chorionic villi as reliable and routine tool inprenatal diagnostics.
- MeSH
- dospělí MeSH
- finanční podpora výzkumu jako téma MeSH
- karyotypizace metody MeSH
- kultivované buňky MeSH
- lidé MeSH
- odběr choriových klků MeSH
- plod MeSH
- prenatální diagnóza metody MeSH
- těhotenství MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- těhotenství MeSH
- ženské pohlaví MeSH
- Publikační typ
- přehledy MeSH
- srovnávací studie MeSH
The frequencies of different types of chromosomal abnormalities are shown in a study performed during 1989 -1996. 32 pathological karyotypes were found, i. e. 1.6 %. The ratio of numerical/structural abnormalities is 1.67. The number of de novo or unexpected structural abnormalities is 67 % from all structural ones in this study. This strongly supports the need of complete cytogenetic analysis.
FISH is a useful method to identify individual chromosomes in a karyotype and to discover their structural changes accompanying genome evolution and speciation. DNA probes for FISH should be chromosome specific and/or exhibit specific patterns of distribution along each chromosome. Such probes are not available in many plants including meadow fescue (Festuca pratensis Huds.), an important forage grass species. In the present study, various DNA repeats identified in Illumina shotgun sequences specific to chromosome 4F of F. pratensis were used as probes for FISH to develop the molecular karyotype of meadow fescue and to reveal a long-range molecular organization of its chromosomes. Five tandem repeats produced specific patterns on individual chromosomes. Their use in combination with probes for rRNA genes enabled the establishment of the molecular karyotype of meadow fescue. Most of the mobile genetic elements were dispersed along all the chromosomes except for the DNA transposon CACTA, which was localized preferentially to telomeric and subtelomeric regions, and a putative LTR element, which was localized to (peri)centromeric regions. Cytogenetic mapping of the 5 tandem repeats in other accessions of meadow fescue showed a highly similar distribution and confirmed the versatility and robustness of these probes.
BACKGROUND: In Turner syndrome (TS), fluorescent in situ hybridization (FISH) karyotyping offers an alternative to classical karyotyping. OBJECTIVE: We tested the added value of FISH karyotyping from lymphocytes (mesodermal origin), buccal cells (ectodermal origin), and a rear-tongue smear (endodermal origin) to determine the 45,X cell line fraction and its impact on patient phenotype. DESIGN AND PATIENTS: Classical karyotyping and three FISH assays were done in 153 girls and women previously diagnosed with TS in four university hospitals. The 45,X cell line fraction was determined for each method and correlated with the major phenotypic signs. RESULTS: Classical karyotyping identified 45,X/46,XX mosaicism in 77/153 subjects (50%), 45,X monosomy in 52/153 (34%), and other karyotypes in 24/153 (16%). FISH from lymphocytes verified 45,X in 47/52 original cases, whereas 4/52 had 45,X/46,XX and 1/52 45,X/47,XYY mosaicism. The 45,X cell line fraction was higher in FISH from lymphocytes compared to classical karyotyping (median 86.4% vs. 70.0%; p < 0.001), while there was no difference for FISH from buccal or rear-tongue smear cells. The mean 45,X cell line fraction was more abundant in patients with several of the characteristic phenotypic signs compared to patients without them (p < 0.01), but the predictive power was insufficient. CONCLUSION: FISH analysis confirmed the findings of classical karyotyping; only a few 45,X monosomy cases were reclassified as mosaics. The 45,X cell line fraction did not show clinically meaningful prediction of the phenotype. FISH analysis of buccal or rear-tongue epithelial cells may be a non-inferior, less invasive alternative to classical karyotyping.
