Taiwanese Journal of Obstetrics & Gynecology 53 (2014) 135
Contents lists available at ScienceDirect
Taiwanese Journal of Obstetrics & Gynecology journal homepage: www.tjog-online.com
Correspondence
Y-chromosome centric (not pericentric) inversion results from centric fission To the Editor, The remarkable observation of a unique dicentric Y chromosome just published in this journal [1] deserves some comments: 1. Because the number of analyzed metaphases was not specified, the possibility of mosaicism remains fully open. 2. The dicentricity of the rearranged Y chromosome appears to be based on the split alphoid block rather than on the number of primary constrictions, which is not given. Moreover, the authors’ assertion “C banding showed that the Y chromosome contained two centromeres” is not supported by the C-banded chromosomes in which centric regions cannot be discerned (see Figure 1B in [1]). In this regard, a plain staining could be instructive. 3. The obvious weakness of both alphoid signals (see Figure 1C in [1]) goes unnoticed. 4. The use of the term “pericentric” to qualify the observed rearrangements is at odds with proper International System of Human Cytogenetic Nomenclature 2013 (ISCN 2013) usage [2]. Although the alternative sanctioned term “paracentric” may better describe the observed rearrangement, the relevant point here is the failure to use “centric fission” to designate the alphoid breakage. Indeed, this rearranged Y chromosome along with a comparable rearrangement of chromosome 12 described as a “centric” inversion [3] but not cited by Kuan et al [1] expands to 10 the types of centric fission products [4]. Accordingly, the ISCN 2013 must be amended. 5. The striking resemblance if not sameness of the reportedly paternal C-banded gonosomes (see Figure 1C in [1]) with the corresponding pair of an 8-week abortus from another family described in a simultaneous paper by the same authors [5] can hardly be dismissed as mere coincidence. Although fluorescence in situ hybridization images are unexpectedly not shown in the companion paper [5], the composition defined by several probes of the Y chromosome with a supposed direct duplication also applies to the inverted Y chromosome in the former report [1];
in particular, the absence of an interstitial Yq subtelomeric signal matches the schema in the TJOG paper [1]. 6. Regarding language and style, I remark on the improper plural usage when referring to the single abnormal Y chromosome in each cell (2nd sentence, p. 443) as well as the unnecessary verbatim reiteration of the sentence on “chromosome breakpoints and mammalian evolution” (pp. 443 and 444). Conflicts of interest: The author has no conflicts of interest to declare.
References [1] Kuan LC, Su MT, Chen M, Kuo PL, Kuo TC. A dicentric Y chromosome resulting from pericentric inversion between the centromere and Yq heterochromatin. Taiwan J Obstet Gynecol 2013;52:443e5. [2] Shaffer LG, McGowan-Jordan J, Schmid M, editors. An international system for human cytogenetic nomenclature. Basel: S Karger; 2013. [3] Silahtaroglu AN, Hacihanefioglu S, Güven GS, Cenani A, Wirth J, Tommerup N, et al. Not para-, not peri-, but centric inversion of chromosome 12. J Med Genet 1998;35:682e4. [4] Perry J, Slater HR, Choo KH. Centric fission e simple and complex mechanisms. Chromosome Res 2004;12:627e40. [5] Kuan LC, Su MT, Kuo PL, Kuo TC. Direct duplication of the Y chromosome with normal phenotype e incidental finding in two cases. Andrologia 2013;45:140e4.
Horacio Rivera* División de Genética, Instituto Mexicano del Seguro Social, CIBO, Guadalajara, Mexico Institute of Human Genetics, CUCS, Universidad de Guadalajara, Guadalajara, Mexico * División
de Genética, CIBO, Instituto Mexicano del Seguro Social, Sierra Mojada 800, C.P. 44340, Guadalajara, Mexico. E-mail address: [email protected]
http://dx.doi.org/10.1016/j.tjog.2013.10.039 1028-4559/Copyright Ó 2014, Taiwan Association of Obstetrics & Gynecology. Published by Elsevier Taiwan LLC. All rights reserved.
Contents lists available at ScienceDirect
Taiwanese Journal of Obstetrics & Gynecology journal homepage: www.tjog-online.com
Correspondence
Y-chromosome centric (not pericentric) inversion results from centric fission To the Editor, The remarkable observation of a unique dicentric Y chromosome just published in this journal [1] deserves some comments: 1. Because the number of analyzed metaphases was not specified, the possibility of mosaicism remains fully open. 2. The dicentricity of the rearranged Y chromosome appears to be based on the split alphoid block rather than on the number of primary constrictions, which is not given. Moreover, the authors’ assertion “C banding showed that the Y chromosome contained two centromeres” is not supported by the C-banded chromosomes in which centric regions cannot be discerned (see Figure 1B in [1]). In this regard, a plain staining could be instructive. 3. The obvious weakness of both alphoid signals (see Figure 1C in [1]) goes unnoticed. 4. The use of the term “pericentric” to qualify the observed rearrangements is at odds with proper International System of Human Cytogenetic Nomenclature 2013 (ISCN 2013) usage [2]. Although the alternative sanctioned term “paracentric” may better describe the observed rearrangement, the relevant point here is the failure to use “centric fission” to designate the alphoid breakage. Indeed, this rearranged Y chromosome along with a comparable rearrangement of chromosome 12 described as a “centric” inversion [3] but not cited by Kuan et al [1] expands to 10 the types of centric fission products [4]. Accordingly, the ISCN 2013 must be amended. 5. The striking resemblance if not sameness of the reportedly paternal C-banded gonosomes (see Figure 1C in [1]) with the corresponding pair of an 8-week abortus from another family described in a simultaneous paper by the same authors [5] can hardly be dismissed as mere coincidence. Although fluorescence in situ hybridization images are unexpectedly not shown in the companion paper [5], the composition defined by several probes of the Y chromosome with a supposed direct duplication also applies to the inverted Y chromosome in the former report [1];
in particular, the absence of an interstitial Yq subtelomeric signal matches the schema in the TJOG paper [1]. 6. Regarding language and style, I remark on the improper plural usage when referring to the single abnormal Y chromosome in each cell (2nd sentence, p. 443) as well as the unnecessary verbatim reiteration of the sentence on “chromosome breakpoints and mammalian evolution” (pp. 443 and 444). Conflicts of interest: The author has no conflicts of interest to declare.
References [1] Kuan LC, Su MT, Chen M, Kuo PL, Kuo TC. A dicentric Y chromosome resulting from pericentric inversion between the centromere and Yq heterochromatin. Taiwan J Obstet Gynecol 2013;52:443e5. [2] Shaffer LG, McGowan-Jordan J, Schmid M, editors. An international system for human cytogenetic nomenclature. Basel: S Karger; 2013. [3] Silahtaroglu AN, Hacihanefioglu S, Güven GS, Cenani A, Wirth J, Tommerup N, et al. Not para-, not peri-, but centric inversion of chromosome 12. J Med Genet 1998;35:682e4. [4] Perry J, Slater HR, Choo KH. Centric fission e simple and complex mechanisms. Chromosome Res 2004;12:627e40. [5] Kuan LC, Su MT, Kuo PL, Kuo TC. Direct duplication of the Y chromosome with normal phenotype e incidental finding in two cases. Andrologia 2013;45:140e4.
Horacio Rivera* División de Genética, Instituto Mexicano del Seguro Social, CIBO, Guadalajara, Mexico Institute of Human Genetics, CUCS, Universidad de Guadalajara, Guadalajara, Mexico * División
de Genética, CIBO, Instituto Mexicano del Seguro Social, Sierra Mojada 800, C.P. 44340, Guadalajara, Mexico. E-mail address: [email protected]
http://dx.doi.org/10.1016/j.tjog.2013.10.039 1028-4559/Copyright Ó 2014, Taiwan Association of Obstetrics & Gynecology. Published by Elsevier Taiwan LLC. All rights reserved.
