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 

作者机构：“Zigote” Genetic and Prenatal Diagnosis Centre Salerno Italy Department of Obstetrics and Gynecology IRCCS Burlo Garofalo University of Trieste Trieste Italy Genetic Department Hosp. “Elena d’Aosta” Naples Italy 

出 版 物：《Open Journal of Genetics》 (遗传学期刊（英文）)

年 卷 期：2013年第3卷第2期

页      面：27-32页

学科分类：1002[医学-临床医学] 100214[医学-肿瘤学] 10[医学] 

主　　题：XX Male SRY Translocation X-Y X Chromosome Inactivation Y Chromosome 

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.