Y-chromosome markers in Turner syndrome: Screening of 130 patients.
BACKGROUND
The presence of Y-chromosome material in patients with Turner syndrome (TS) is a risk factor for the development of gonadoblastoma. Cytogenetic analysis detects Y-chromosome mosaicism in about 5% of Turner patients. However, if Y-chromosome sequences are present in only a few cells, they may be missed by routine analysis. The use of molecular techniques to detect the presence of Y-chromosome fragments in such patients is becoming increasingly important.


OBJECTIVE
The objective of our study was to analyze cryptic Y-chromosome derivatives in Hungarian TS patient population by real-time PCR (RT-PCR).


METHODS
Cytogenetic and RT-PCR methods were used to examine peripheral blood DNA of 130 Hungarian patients with TS for the presence of Y-chromosome. With RT-PCR, 4 regions throughout the Y-chromosome were analyzed.


RESULTS
Initial cytogenetic karyotyping assessing 10-50 metaphases revealed 3 patients with Y-chromosome positivity. RT-PCR revealed further 6 patients with Y-chromosome, who were initially considered as Y-negatives by standard kayotyping. The consecutive cytogenetic analysis of a large number (about 100) of metaphases (in 5 patients) and/or FISH (in 6 patients) however, also confirmed the presence of the Y-chromosome in these patients. Prophylactic gonadectomy was carried out in all 9 patients and 1 of them was diagnosed as having bilateral gonadoblastoma without clinical symptoms.


CONCLUSIONS
We recommend a routine molecular screening for hidden Y-chromosome sequences in Turner patients, who are negative for Y-chromosome by conventional cytogenetic analysis, in order to calculate the future risk of developing gonadoblastoma.
Sallai
A
A
2nd Department of Pediatrics, Semmelweis University, H-1094 Budapest, Hungary. agnes.sallai@gmail.com
Sólyom
J
J
Dobos
M
M
Szabó
J
J
Halász
Z
Z
Ságodi
L
L
Niederland
T
T
Kozári
A
A
Bertalan
R
R
Ugocsai
P
P
Fekete
G
G
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D041322:Chromosomes, Human, Y / Q000235:genetics*; D020732:Cytogenetic Analysis; D005260:Female; D005819:Genetic Markers / Q000235:genetics*; D018238:Gonadoblastoma / Q000235:genetics; D006801:Humans; D006814:Hungary; D007223:Infant; D007231:Infant, Newborn; D007621:Karyotyping; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012307:Risk Factors; D014424:Turner Syndrome / Q000235:genetics*; D055815:Young Adult
D005819:Genetic Markers