SRY in an XX male does not influence random chromosome X inactivation: Cytogenetic evidence. Definition of the boundaries of the translocated Y segment through FISH and PCR-RT in a case report and review of the literature  

作　　者：Mariano Stabile Vincenzo Altieri Rosa Salzillo Panfilo Marrollo Guglielmo Stabile Tina Iuorio Bianca Moscato 

机构地区：[1]“Zigote” Genetic and Prenatal Diagnosis Centre, Salerno, Italy [2]Department of Obstetrics and Gynecology, IRCCS Burlo Garofalo, University of Trieste, Trieste, Italy [3]Genetic Department, Hosp. “Elena d’Aosta”, Naples, Italy

出　　处：《Open Journal of Genetics》2013年第2期27-32,共6页遗传学期刊（英文）

摘　　要：We report a case of an SRY positive XX male. The phenotype was completely masculinised except for the reduced facial hair;testes were small, and azoospermia was present. The patient’s metaphases, coloured with acridine-orange to reveal the late replicating X chromosome, were sequentially hybridised with SRY and X centromeric probes: a random X chromosome inactivation pattern (XCIP) was present, with SRY present about half the time on both the active X and the inactive X. The most likely hypothesis is that the translocated SRY gene escaped inactivation as part of the entire X Pseudo Autosomal telomeric Region 1 (PAR 1). This hypothesis can explain the masculine phenotype, which would be incompatible with a halved expression of SRY. Review of the literature about the association of 46, XX males with a specific XCI pattern is made. The analysis of region AZF and QF-PCR for Y polymorphic loci allowed us to define the boundaries of the translocated Y segment as restricted to the region around the SRY locus. Chromosomal fragility analysis, using SCE (Sister Chromatid Exchanges), ruled out chromosomal fragility as a predisposing factor in the proband’s father;in addition, no chromosome Y polymorphic variant (inversion, Y qh +/﹣), was present in the proband’s father. However, like the AZF region c microdeletions and PRKX/PRKY translocation XX males, a particular Y haplotype could be also in this case a predisposing factor.We report a case of an SRY positive XX male. The phenotype was completely masculinised except for the reduced facial hair;testes were small, and azoospermia was present. The patient’s metaphases, coloured with acridine-orange to reveal the late replicating X chromosome, were sequentially hybridised with SRY and X centromeric probes: a random X chromosome inactivation pattern (XCIP) was present, with SRY present about half the time on both the active X and the inactive X. The most likely hypothesis is that the translocated SRY gene escaped inactivation as part of the entire X Pseudo Autosomal telomeric Region 1 (PAR 1). This hypothesis can explain the masculine phenotype, which would be incompatible with a halved expression of SRY. Review of the literature about the association of 46, XX males with a specific XCI pattern is made. The analysis of region AZF and QF-PCR for Y polymorphic loci allowed us to define the boundaries of the translocated Y segment as restricted to the region around the SRY locus. Chromosomal fragility analysis, using SCE (Sister Chromatid Exchanges), ruled out chromosomal fragility as a predisposing factor in the proband’s father;in addition, no chromosome Y polymorphic variant (inversion, Y qh +/﹣), was present in the proband’s father. However, like the AZF region c microdeletions and PRKX/PRKY translocation XX males, a particular Y haplotype could be also in this case a predisposing factor.

关 键 词：XX MALE SRY Translocation X-Y X CHROMOSOME INACTIVATION Y CHROMOSOME 

分 类 号：R73[医药卫生—肿瘤]