Cytogenetic and molecular investigations of Y chromosome sequences and their role in Turner syndrome.
It has been proposed that all live born females with Turner syndrome carry a cell line containing two sex chromosomes, which may be present at a low level of mosaicism (Hook & Warburton, 1983; Hassold et al. 1985; 1988; Connor & Loughlin, 1989). If the second sex chromosome is a Y, these patients are at risk of developing gonadoblastoma. In this study, 50 patients found to have a 45,X karyotype by conventional cytogenetic analysis, were screened by the polymerase chain reaction (PCR), for the presence of Y chromosome sequences. Two patients were positive for six of the eight Y chromosome loci tested and additional cytogenetic analysis confirmed the presence of a marker chromosome, in 8% and 3% of cells respectively. Fluorescence in situ hybridization (FISH) was used to confirm that the markers were of Y chromosome origin and helped to elucidate their structure. In addition, four other patients were found to have a Y chromosome by initial routine cytogenetic analysis. FISH, in conjunction with PCR, elucidated the structure of the Y chromosomes. This study illustrates the value of using a combination of cytogenetic and molecular techniques, to identify Y chromosome sequences in Turner syndrome.
Galton Laboratory, University College London, UK. c.quilter@ucl.ac.uk
C R
CR
Quilter
K
K
Taylor
G S
GS
Conway
N
N
Nathwani
J D
JD
Delhanty
D003582:Cytogenetics; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D009030:Mosaicism; D016133:Polymerase Chain Reaction / Q000379:methods; D014424:Turner Syndrome / Q000235:genetics*; D014998:Y Chromosome