search for




 

Prenatal diagnosis of an unbalanced translocation between chromosome Y and chromosome 15 in a female fetus
J Genet Med 2016;13:95-98
Published online December 31, 2016;  https://doi.org/10.5734/JGM.2016.13.2.95
© 2016 Korean Society of Medical Genetics.

Dongsook Lee1,2, Heeju Park1, Sanha Kwak1, Soomin Lee1, Sanghee Go1, Sohyun Park1, Sukyung Jo1, Kichul Kim1, Seunggwan Lee2, and Doyeong Hwang1,*

1Research Center of Fertility & Genetics, Hamchoon Women’s Clinic, Seoul, Korea,
2Department of Health and Environmental Science, Korea University, Seoul, Korea
Doyeong Hwang, Ph.D. Research Center of Fertility & Genetics, Hamchoon Women’s Clinic, 10 Seochojungang-ro 8-gil, Seocho-gu, Seoul 06643, Korea. Tel: +82-2-522-0123, Fax: +82-2-522-2388, E-mail: doyhwang@hamchoon.com
Received November 16, 2016; Revised December 4, 2016; Accepted December 4, 2016.
cc This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract

We report the prenatal diagnosis of an unbalanced translocation between chromosome Y and chromosome 15 in a female fetus. Cytogenetic analysis of parental chromosomes revealed that the mother had a normal 46,XX karyotype, whereas the father exhibited a 46,XY,der(15)t(Y;15) karyotype. We performed cytogenetic analysis of the father’s family as a result of the father and confirmed the same karyotype in his mother and brother. Fluorescence in situ hybridization and quantitative fluorescent-polymerase chain reaction analysis identified the breakpoint and demonstrated the absence of the SRY gene in female members. Thus, the proband inherited this translocation from the father and grandmother. This makes the prediction of the fetal phenotype possible through assessing the grandmother. Therefore, we suggest that conventional cytogenetic and molecular cytogenetic methods, in combination with family history, provide informative results for prenatal diagnosis and prenatal genetic counseling.

Keywords : Prenatal diagnosis, der(15)t(Y;15)(q12;p11), Sex chromosome aberrations, Fluorescence in situ hybridization, Quantitative fluorescent PCR
Introduction

Translocations involving the Y chromosome and an autosomal chromosome are very rare, occurring in approximately 1/2,000 of the general population. The most frequent translocation of this type occurs between the heterochromatin of the long arm of chromosome Y and the short arm of chromosome 15 [1,2]. This may be the result of a frequent sequence homology based association of the 15p and Yq heterochromatin, during the pachytene stage of male meiosis [3]. The breakpoints are frequently located within the chromosome 15p11-15p13 and Yq11.23-Yq12 regions. These types of translocations are equally found in male and female patients, and carriers of t(Y;15) usually have a normal phenotype [2,4].

We report the prenatal diagnosis of an unbalanced translocation between chromosome Y and chromosome 15 in a female fetus, inherited from a paternal carrier. Molecular cytogenetic methods were used to cytogenetically characterize the der(15) translocation, and family history was helpful in prenatal counseling.

Case

A 40-year-old pregnant woman was referred for amniotic fluid sampling at 16 weeks and three days due to advanced maternal age. Quantitative fluorescent polymerase chain reaction (QF-PCR) was performed in uncultured amniocytes using a set of short tandem repeat markers for chromosomes 13, 18, 21, X, and Y (Cybergene AB, Stockholm, Sweden). QF-PCR results revealed one abnormal pattern (X22) representing two pseudoautosomal regions PAR1 and PAR2 (X22 and DXYS218 ) (Fig. 1).

Cytogenetic analysis results showed the presence of additional material on the p-arm of one chromosome 15 (III-1 in Fig. 2). The karyotypes of the proband’s parents were examined to determine if this atypical chromosome 15 was inherited or occurred de novo. Cytogenetics results revealed that the proband’s father had the same der(15) chromosome, while the proband’s mother exhibited a normal karyotype. Dark G-banding observed on the p-arm structure of the der(15) showed that it was likely to correspond to heterochromatin (II-1 in Fig. 2).

We characterized the der(15) chromosome using fluorescence in situ hybridization (FISH) analysis. FISH analysis was performed by hybridizing combined probes targeting chromosome Y and centromeric 15 (CEP15) (Fig. 3). Finally, the proband’s karyotype was interpreted as 46,XX,der(15)t(Y;15)(q12;p11)pat. To predict the phenotype of the proband, we conducted a cytogenetic analysis of the father’s family. This analysis revealed that the father’s mother and brother carried the same der(15) chromosome (I-2 and II-3 in Fig. 2). QF-PCR results of the proband’s grandmother (I-2 in Fig. 2) revealed the same pattern for the X22 marker as the proband (not shown). Therefore, through the grandmother we can predict the phenotype of the fetus for purposes of genetic counseling.

Discussion

In prenatal diagnosis, prediction of phenotypes caused by unknown chromosome fragments or translocations is big dilemma. Here, the unknown chromosome fragment identified during prenatal diagnosis was very confusing. However, QF-PCR results suggested that the abnormal chromosome related structural abnormality was found. QF-PCR is a very powerful tool for prenatal diagnosis of the most commoen aneuploidies. However, the detection of a trisomic pattern in only one marker, is more problematic. In such cases, parents should be tested to identify the presence of a duplication, and to rule out the possibility of partial trisomy. In the case of X22, heterochromatic Y chromosome material has already been described [5,6].

In this case, the translocation origin and breakpoints were determined through FISH using CEP 15, and Y specific probes. Our results demonstrate that standard karyotyping, in combination with FISH, is useful for the detection of rare chromosomal rearrangements. Some cases with Prader-Willi syndrome (PWS) exhibit translocations involving chromosome 15 with deletion of PWS regions [2,7-10]. However, by using CEP 15 (Fig. 3), we confirmed that the breakpoint in this case does not include the PWS region.

Accurate identification of der(15) chromosomal content during prenatal cytogenetic analysis may facilitate the prediction of the fetal phenotype. Therefore, characterizing the der(15) chromosome using FISH is recommended. The der(15)t(Y;15)(q12;p13) translocation identified in the present work is the most common form of Y-autosome translocation. While this karyotype appears unbalanced, examination of the family history and identification of the same chromosome in the paternal grandmother (I-1 in Fig. 2), reveals that the phenotype of the proband is predicted to be normal female.

Therefore we suggest that conventional cytogenetic methods, combined with molecular cytogenetic methods and family history, are very informative for prenatal diagnosis and prenatal genetic counseling.

Figures
Fig. 1.

Electrophoregram of prenatal diagnostic quantitative fluorescent polymerase chain reaction (QF-PCR; Cybergene AB, Stockholm, Sweden). A total of five short tandem repeats from chromosome 13 (D13S256, D13S303, D13618, D13S631, D13S634), five from chromosome 18 (D18S386, D18S391, D18S535, D18S858, D18S976), six from chromosome 21 (D21S11, D21S1411, D21S1412, D21S1413, D21S1435, D21S1444), three from chromosome X (DXS996, DXS1283, P39) and two from the pseudoautosomal regions PAR1 and PAR2 (X22 and DXYS218) were included. AMXY and SRY were also included. Prenatal testing results, revealed that chromosomes 13, 18 and 21 were normal. AMXY and chromosome X markers indicated that the proband was SRY negative and female, respectively. One (X22, arrow) of the psudoautosomal regions PAR1 and PAR2 (X22 and DXYS218) was abnormal. The grandmother’s results were the same as those of the proband (not shown).


Fig. 2.

Family pedigrees and cytogenetic characterization of the der(15) translocation.


Fig. 3.

Fluorescence in situ hybridization results showed the presence of two chromosome 15 positive regions (arrows). The derived chromosome 15 of cultured amniocytes from III-1 contains Yq12 (I-2 was same results. Not shown). The probe for chromosome Yq12 (DYZ1, satellite III; Vysis, Chicago, IL, USA) is labelled in red. The probe, for chromosome 15 CEP (D15Z1; Vysis) is labeled in green. (A) Background 4’,6-diamidino-2-phenylindole (DAPI) image, B) inverted DAPI image.


References
  1. Onrat ST, Söylemez Z, and Elmas M. 46,XX, der(15), t(Y;15)(q12;p11) karyotype in an azoospermic male. Indian J Hum Genet 2012;18:241-5.
    Pubmed KoreaMed CrossRef
  2. Chen Y, Chen G, Lian Y, Gao X, Huang J, and Qiao J. A normal birth following preimplantation genetic diagnosis by FISH determination in the carriers of der(15)t(Y;15)(Yq12;15p11) translocations: two case reports. J Assist Reprod Genet 2007;24:483-8.
    Pubmed KoreaMed CrossRef
  3. Alitalo T, Tiihonen J, Hakola P, and de la Chapelle A. Molecular characterization of a Y;15 translocation segregating in a family. Hum Genet 1988;79:29-35.
    Pubmed CrossRef
  4. Chen PY, Yen JH, Cheng CF, Chen PC, Li YS, and Li TY et al. Prenatal diagnosis of the maternal derivative chromosome der(15)t(Y;15)(q12;p13) in a dizygotic twin pregnancy. Tzu Chi Med J 2016;28:176-9.
    CrossRef
  5. Badenas C, Rodríguez-Revenga L, Morales C, Mediano C, Plaja A, and Pérez-Iribarne MM et al. Assessment of QF-PCR as the first approach in prenatal diagnosis. J Mol Diagn 2010;12:828-34.
    Pubmed KoreaMed CrossRef
  6. Cirigliano V, Voglino G, Ordoñez E, Marongiu A, Paz Cañadas M, and Ejarque M et al. Rapid prenatal diagnosis of common chromosome aneuploidies by QF-PCR, results of 9 years of clinical experience. Prenat Diagn 2009;29:40-9.
    Pubmed CrossRef
  7. Disteche CM, Brown L, Saal H, Friedman C, Thuline HC, and Hoar DI et al. Molecular detection of a translocation (Y;15) in a 45,X male. Hum Genet 1986;74:372-7.
    Pubmed CrossRef
  8. Gal A, Weber B, Neri G, Serra A, Müller U, and Schempp W et al. A 45,X male with Y-specific DNA translocated onto chromosome 15. Am J Hum Genet 1987;40:477-88.
    Pubmed KoreaMed
  9. Morel F, Duguépéroux I, McElreavey K, Le Bris MJ, Herry A, and Parent P et al. Transmission of an unbalanced (Y;1) translocation in Brittany, France. J Med Genet 2002;39:e52.
    Pubmed KoreaMed CrossRef
  10. Hoshi N, Fujita M, Mikuni M, Fujino T, Okuyama K, and Handa Y et al. Seminoma in a postmenopausal woman with a Y;15 translocation in peripheral blood lymphocytes and a t(Y;15)/45,X Turner mosaic pattern in skin fibroblasts. J Med Genet 1998;35:852-6.
    Pubmed KoreaMed CrossRef


June 2017, 14 (1)
Full Text(PDF) Free

Social Network Service
Services

Cited By Articles
  • CrossRef (0)

Author ORCID Information