RESUMO
We present a case of myeloid metaplasia with myelofibrosis (MM/MF), with tetrasomy 8 as the sole cytogenetic abnormality detected by conventional cytogenetic studies. Tetrasomy 8 was also detected by in situ interphase studies and confirmed by chromosome painting in metaphase. To our knowledge, this is the first case of MM/MF with tetrasomy 8. Noteworthy is the association with neurofibromatosis.
Assuntos
Cromossomos Humanos Par 8 , Mielofibrose Primária/complicações , Mielofibrose Primária/genética , Adulto , Feminino , Humanos , Hibridização in Situ Fluorescente , Neurofibromatoses/complicações , Poliploidia , Mielofibrose Primária/patologia , TrissomiaRESUMO
The reliability of FISH was appraised using probes for the X and Y chromosome and for chromosomes 12 and 18 in prenatal and adult interphase nuclei. Detection of a single hybridization spot proved to be quite reliable (80-92% positive nuclei). Detection of two hybridization spots was more difficult; percentages of nuclei showing two signals varied between 62-72%. The percentages of nuclei with the correct number of spots was higher in the metaphases occasionally found. Thus, FISH may complement but not replace cytogenetic analysis. For sex determination and for the detection of mosaicism, we suggest the use of two different probes in separate regions of the same preparation.
Assuntos
Hibridização in Situ Fluorescente/métodos , Diagnóstico Pré-Natal/métodos , Líquido Amniótico/citologia , Vilosidades Coriônicas , Cromossomos Humanos Par 12 , Cromossomos Humanos Par 18 , Sondas de DNA , Feminino , Sangue Fetal/citologia , Humanos , Gravidez , Cromossomos SexuaisAssuntos
DNA Satélite/genética , Polimorfismo Genético , Translocação Genética , Cromossomo Y , Feminino , Humanos , MasculinoRESUMO
A synaptonemal complex (SC) analysis was carried out in male mice heterozygous (CHT/+) for three Robertsonian translocations. All pachytene preparations studied showed the presence of three trivalents. At early pachytene, the nonhomologous centromeric regions of the acrocentric chromosomes were unpaired. Heterosynapsis subsequently took place with complete pairing of the trivalents. Association between one of the three trivalents and the sex vesicle was observed in 30.4% of the nuclei. Association between the unpaired regions of two trivalents was present in 14.4% of the cells, suggesting that the relationship between unpaired regions of structural rearrangements and the X-Y bivalent may simply reflect the tendency of unpaired regions to establish end-to-end associations or heterosynapses among them, which are usually resolved during the pachytene stage of prophase I. Since the sex bivalent always has unpaired regions, these associations often affect the sex chromosomes.
