Reddy P P, Papenhausen P R, Suh Y M, Riddick L M, Calvano C J, Mandell J
Division of Urology, Albany Medical College, New York, USA.
J Urol. 1997 Sep;158(3 Pt 2):1305-7.
The mammalian sex determining gene, sex region Y chromosome (SRY), is now firmly established as the testis determining locus. The SRY locus is close to the short arm Y terminus and just distal to zinc finger Y region (ZFY), a locus previously thought to be involved in testicular differentiation and the male phenotype. We report on XX sex reversal, a rare sex chromosomal disorder in humans.
Routine amniocentesis revealed an XX fetal karyotype, although at birth the neonate was phenotypically male. Radiographic evaluation showed a normal male urethra and the absence of any female internal genitalia. Subsequent molecular analysis with polymerase chain reaction amplified sequences of the SRY and ZFY loci were positive.
This case is the fourth in our series of XX sex reversed male individuals and to our knowledge the first to be diagnosed perinatally. In all cases the SRY and ZFY loci are present, presumably on the paternal X chromosome, as well as a Klinefelter phenotype. These sex reversing translocations are thought to be due to an unequal meiotic recombination of the distal X and Y short arms during male gametogenesis. The tendency for XY translocations to break between the SRY and ZFY loci was not seen in these apparent microtranslocation cases.
These 4 cases demonstrate the usefulness of molecular followup of clinically perplexing sexual discordance. We conclude that SRY and ZFY polymerase chain reaction amplification studies should be performed when sexual discrepancies are noted on prenatal ultrasound and karyotype analysis.
哺乳动物性别决定基因，即Y染色体性别决定区（SRY），现已被确认为睾丸决定位点。SRY位点靠近Y染色体短臂末端，位于锌指Y区域（ZFY）的远端，ZFY位点以前被认为与睾丸分化和男性表型有关。我们报告了一例XX性反转病例，这是一种罕见的人类性染色体疾病。
常规羊膜穿刺术显示胎儿核型为XX，尽管出生时新生儿表型为男性。影像学评估显示男性尿道正常，无任何女性内生殖器。随后采用聚合酶链反应对SRY和ZFY位点的序列进行分子分析，结果均为阳性。
该病例是我们系列XX性反转男性个体中的第四例，据我们所知，是第一例在围产期被诊断出的病例。在所有病例中，SRY和ZFY位点均存在，推测位于父源X染色体上，同时伴有克兰费尔特综合征表型。这些性反转易位被认为是由于男性配子发生过程中X和Y短臂远端的减数分裂不均等重组所致。在这些明显的微易位病例中，未发现XY易位在SRY和ZFY位点之间断裂的倾向。
这4例病例证明了对临床令人困惑的性不一致进行分子随访的有用性。我们得出结论，当产前超声和核型分析发现性差异时，应进行SRY和ZFY聚合酶链反应扩增研究。
