Nested polymerase chain reaction study of 53 cases with Turner's syndrome: is cytogenetically undetected Y mosaicism common?
Turner's syndrome patients with Y mosaicism face a high risk of developing gonadoblastoma. Cytogenetic analysis can fail to detect rare cells bearing a normal or structurally abnormal Y chromosome (low level Y mosaicism). We screened 53 individuals with Turner's syndrome for presence of sex-determining region Y (SRY), the testis-specific protein, Y encoded, gene, and the Y centromeric DYZ3 repeat using nested polymerase chain reaction (PCR). Thirty girls (57%) had the 45,X karyotype, determined through standard analysis of blood lymphocytes. The remaining 23 girls (43%) were mosaics and/or had structural abnormalities in 1 X-chromosome. Genomic DNA from blood leukocytes was amplified using 2 rounds of PCR. This method was sensitive enough to detect 0.0001% male DNA on a female background. None of 53 Turner's syndrome cases was positive for Y-specific loci after the first round of PCR. After the second round, 2 of 53 Turner's syndrome cases were positive for SRY mapping to the distal short arm of chromosome Y. In 1 SRY-positive subject, the karyotype was 45,X, and in the other, it was 46,Xi(Xq). None of 53 Turner's syndrome individuals, including the 2 SRY-positive subjects, were positive for the testis-specific protein, Y encoded, gene on the proximal short arm of chromosome Y or the centromeric DYZ3 repeat. These data exclude low level Y mosaicism in almost all Turner's syndrome cases tested.
University Children's Hospital, Tübingen, Germany.
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G
Binder
A
A
Koch
E
E
Wajs
M B
MB
Ranke
D001483:Base Sequence; D002648:Child; D003582:Cytogenetics / Q000379:methods; D005260:Female; D006801:Humans; D008969:Molecular Sequence Data; D009030:Mosaicism; D015345:Oligonucleotide Probes / Q000235:genetics; D016133:Polymerase Chain Reaction / Q000379:methods; D012680:Sensitivity and Specificity; D014424:Turner Syndrome / Q000235:genetics*; D014998:Y Chromosome
D015345:Oligonucleotide Probes