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Abstract

We would like to thank Álvarez-Nava et al. for their letter and their interest in our work (1Plevraki E. Kita M. Goulis D.G. Hatzisevastou-Loukidou H. Lambropoulos A.F. Avramides A. Bilateral ovarian agenesis and the presence of the testis specific protein 1-Y-linked gene: two new features of Mayer-Rokitansky-Küster-Hauser syndrome.Fertil Steril. 2004; 81: 689-692Abstract Full Text Full Text PDF PubMed Scopus (27) Google Scholar). False-positive results of the nested polymerase chain reaction (nested PCR) usually arise because of contamination with PCR products (2Lo Y. Patel P. Sampietro M. Gillmer M.D.G. Fleming K.A. Wainscoat J.S. Detection of single-copy fetal DNA sequence from maternal blood.Lancet. 1990; 335: 1463-1464Abstract PubMed Scopus (141) Google Scholar). In our study, several precautions were taken to avoid contamination. Pre- and post-PCR workspaces were strictly separated so that carry-over of amplified DNA sequences to new PCR reactions was prevented. Each PCR reaction contained one normal female (nulliparous young girl) and one template-free sample for early detection of contamination. In our positive PCRs, the bands of the amplified products were not weak, which excludes the existence of closely related, cross-amplifying sequences elsewhere in the genome. In the Alvarez-Nava et al. letter, it is not clear that the control group consisted of normal woman without prior pregnancies of a male embryo. The presence of the testis-specific protein Y-linked gene (TSPY) among normal women might be explained by microchimerism in the case of a past pregnancy of a male embryo. Recent studies have now confirmed the existence of fetal cells (including lymphocytes) in maternal blood, and molecular genetic techniques have enhanced the detection of fetal-specific gene sequences in candidate fetal cells isolated from maternal blood (3Adams K.M. Nelson J.L. Microchimerism: an investigative frontier in autoimmunity and transplatation.JAMA. 2004; 291: 1127-1131Crossref PubMed Scopus (181) Google Scholar, 4Bianchi D.W. Zickwolf G.K. Weil G.J. Sylvester S. DeMaria M.A. Male fetal progenitor cells persist in maternal blood for as long as 27 years postpartum.Proc Natl Acad Sci U S A. 1996; 93: 705-708Crossref PubMed Scopus (1035) Google Scholar). The detection of persisting fetal cells is achieved only by sensitive methods, such as nested PCR, because of the low frequencies in maternal circulation. Y-chromosome sequences have been identified in maternal blood even as early as 6 weeks' gestation in cases of a male embryo (2Lo Y. Patel P. Sampietro M. Gillmer M.D.G. Fleming K.A. Wainscoat J.S. Detection of single-copy fetal DNA sequence from maternal blood.Lancet. 1990; 335: 1463-1464Abstract PubMed Scopus (141) Google Scholar). At the same time, male DNA has been also recognized in women with early termination of pregnancies (4Bianchi D.W. Zickwolf G.K. Weil G.J. Sylvester S. DeMaria M.A. Male fetal progenitor cells persist in maternal blood for as long as 27 years postpartum.Proc Natl Acad Sci U S A. 1996; 93: 705-708Crossref PubMed Scopus (1035) Google Scholar). Thus, male fetal cells engraft and might be detected in maternal circulation for as long as 27 years postpartum (3Adams K.M. Nelson J.L. Microchimerism: an investigative frontier in autoimmunity and transplatation.JAMA. 2004; 291: 1127-1131Crossref PubMed Scopus (181) Google Scholar). The indication for gonadal biopsies, performed in the two Mayer-Rokitansky-Küster-Hauser syndrome (MRKH) patients of our study, was indeed the presence of TSPY gene. Thus, TSPY might be an oncogene and is a strong candidate gene within the gonadoblastoma locus on the Y chromosome. Although rare, ovarian cancer has been reported among MRKH patients (5Ghirardi G. Magnani A. Mayer-Rokitansky-Küster-Hauser syndrome and ovarian cancer Report of a case.Clin Exp Obstet Gynecol. 1995; 22: 411-413Google Scholar). At this point, the presence of the TSPY gene is not adequate to recommend gonadectomy to our patients, but we believe that individuals with MRKH syndrome must be followed periodically because they might be at higher risk of developing ovarian neoplasms. Nested polymerase chain reaction—not ready for gold standard status yet!Fertility and SterilityVol. 82Issue 5PreviewWe have read with great interest the article by Plevraki et al. (1) on Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome. The investigators report the occurrence of testes-specific protein 1 Y-linked (TSPY) gene, identified by nested polymerase chain reaction (PCR) analysis in 2 of 6 MRKH patients, and propose this finding as a new feature of the condition. To test whether Y-chromosome sequences are associated with the pathogenesis of MRKH, we tested the presence of these sequences on peripheral-blood-lymphocytes-DNA (PBL-DNA) from 12 Venezuelan patients with this disease. Full-Text PDF