Characterization of a prenatally diagnosed de novo der(X)t(X;Y)(q27;q11.23) of fetus.
- Author:
Sang Hee PARK
1
;
Sung Han SHIM
;
Yong Wook JUNG
;
Da Hee KIM
;
Su Jin KANG
;
Sun Ok PARK
;
Dong Hyun CHA
Author Information
- Publication Type:Case Report
- Keywords: Prenatal diagnosis; X chromosome; Xq; Yq translocation
- MeSH: Adult; Chorionic Villi Sampling; Cytogenetic Analysis; Female; Fetus*; Fluorescence; Genetic Counseling; Humans; In Situ Hybridization; Karyotype; Nuchal Translucency Measurement; Parents; Pregnancy; Prenatal Diagnosis; Twins; X Chromosome; X Chromosome Inactivation; Y Chromosome
- From:Journal of Genetic Medicine 2014;11(1):16-21
- CountryRepublic of Korea
- Language:English
- Abstract: A 31-year-old woman, who was pregnant with twins, underwent chorionic villus sampling because of increased nuchal translucency in one of the fetuses. Cytogenetic analysis showed a normal karyotype in the fetus with increased nuchal translucency. However, the other fetus, with normal nuchal translucency, had a derivative X chromosome (der(X)). For further analysis, fluorescence in situ hybridization (FISH) and additional molecular studies including fragile X analysis were performed. FISH analysis confirmed that the Y chromosome was the origin of extra segment of the der(X). The X-chromosome breakpoint was determined to be at Xq27 by FMR1 CGG repeat analysis, and the Y-chromosome breakpoint was determined to be at Yq11.23 by the Y chromosome microdeletion study. To predict the fetal outcome, the X-inactivation pattern was examined, and it revealed non-random X inactivation of the der(X). To the best of our knowledge, the identification of an unbalanced Xq;Yq translocation at prenatal diagnosis has never been reported. This study was performed to identify precise breakpoints and the X-inactivation pattern as well as to provide the parents with appropriate genetic counseling.
