| Molecular Genetic Screening for the SRY(Sex Determining Region of the Y chromosme) Gene in Turner Syndrome Patients |
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Jung-Yeon Shim, Han-Wook Yoo |
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Department of Pediatrics, Asan Medical Center, College of Medicine, Ulsan University, Seoul, Korea |
| Turner증후군 환자에서 성결정 SRY (Sex Determining Region of the Y chromosome) 유전자의 분자 유전학적 검색 |
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심정연, 유한욱 |
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울산대학교 의과대학 소아과학교 |
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| Abstract |
Purpose
: Turner syndrome is among the most common cytogenetic abnormalities associated with
X chromosome. In only 40-60% of Turner syndrome, 45,X monosomy is found and the high
prenatal mortality of non-mosaic 45,X has led to the hypothesis that liveborn 45,X individuals may
be cryptic mosaics. The presence of Y chromosome is significant because it predisposes affected
individuals with Turner syndrome to gonadoblastoma formation. Until recently, genotype analysis
was based mainly on classical cytogenetic techniques, yet it has some limitations to detect Y-derived
chromosomal material. In this study, we aimed at molecular genetic screening for the presence of
Y-chromosome or derivative by using polymerase chain reaction (PCR).
Methods
: Cytogenetic analysis was performed in patients with clinical features of Turner
syndrome. We examined the presence of products of the Y chromosome by polymerase chain
amplification of the sex-determining region of the Y chromosome(SRY) gene and repetitive
sequences located at the centromeric region(DYZ3), using genomic DNA obtained from peripheral
blood lymphocytes of 19 patients with Turner syndrome.
Results
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1) Among 19 patients cytogenetically studied, 12 patients carried 45,X; four patients, structural
anomalies of the X chromosome; three were mosaics for 45,X, one with 46,XY, another with
46,X+mar, another with 46,X,i(Xq).
2) Three patients yielded a PCR product derived from the SRY gene. In two of them, an Y
chromosomal material was not visualized by cytogenetic analysis.
3) Among 3 patients with positive signals for the SRY gene, one patient was negative for
DYZ3, suggesting that only a small portion of Y was present.
Conclusion
: The molecular genetic analysis for the detection of Y chromosome is more
sensitive than cytogenetic analysis. Prophylactic gonadectomy may be justified in Turner
syndrome patients with Y-derived chromosomal material to reduce the risk for the development
of gonadoblastoma. |
| Key Words:
SRY(Sex determining Region of the Y chromosome) gene, Turner syndrome, Gonadoblastoma |
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