ESPE Abstracts (2014) 82 P-D-3-2-965

Mosaicism Ratios of 45,X to 46,X IdicY Explained a Phenotype in a Case with Mixed Gonadal Dysgenesis

Megumi Hatano, Ryuji Fukuzawa & Yukihiro Hasegawa

Tokyo Metropolitan Children’s Medical Center, Tokyo, Japan

Background: Patients with mixed gonadal dysgenesis (MGD), whose prototypical karyotype is 45,X/46,XY may manifest complications characteristic of Turner’s syndrome. We here present a 10-year-old male with MGD who had coarctation of aorta. At birth, he was found to have hypospadias, bifid scrotum and cryptorchidism. Chromosomal analysis of lymphocytes revealed a karyotype of 46,X idic Y (23)/45,X (7). Left gonadectomy was performed in infancy and the removed gonad showed streak gonad with a region of testicular tissue, compatible with MGD. At the age of 10 years, coarctation of the aorta was pointed out by chance.

Objective and hypotheses: The objective of this study was to see mosaicism ratios of the removed gonad and aortic tissue. We hypothesize that mosaicism ratios of 45,X/46,XY varies among tissues, and tissues with a higher ratio of 45,X to 46,XY are more likely to exhibit phenotypes of Turner’s syndrome.

Method: The mosaicism ratios of the removed gonad and aortic tissue were estimated by fluorescent immunostaining with probes to identify X centromere-specific repeat sequence and Yp11.2.

Results: The percentages of Yp11.2 negative cells in the left gonad and aortic tissue were 80 and 90% respectively. In contrast, the percentages of Yp11.2 negative cells in the aortic tissue from 46,XX and 46,XY individuals were more than 95% and <5%, respectively.

Conclusion: Mosaicism ratios in tissues may explain phenotypes in MGD, and further studies to prove this should be conducted in a larger number of cases.

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