journal article
Open Access
Oct 01, 2025
Ring Y chromosome as an unusual cause of severe oligozoospermia
Abstract
Summary
We report a 27-year-old male with a rare chromosomal anomaly involving a ring Y chromosome (RCY). Our patient presented with severe oligozoospermia in the absence of other overt phenotypic abnormalities and was ultimately found to have mosaicism involving a ring Y chromosome. This case highlights the importance of considering structural Y chromosome abnormalities in the evaluation of male infertility, even in individuals with otherwise normal pubertal development and secondary sexual characteristics.
Learning points
RCY is a rare but important genetic cause of male infertility and should be considered in the evaluation of severe oligozoospermia or azoospermia.
The clinical phenotype of RCY ranges from a normal male phenotype with infertility to phenotypic females with features of Turner syndrome. This is influenced by the presence or absence of Y-linked genes and the degree of 45,X mosaicism.
The presence of a 45,X cell line in individuals with RCY mosaicism has been associated with gonadal anomalies, particularly dysgenesis and cryptorchidism.
We report a 27-year-old male with a rare chromosomal anomaly involving a ring Y chromosome (RCY). Our patient presented with severe oligozoospermia in the absence of other overt phenotypic abnormalities and was ultimately found to have mosaicism involving a ring Y chromosome. This case highlights the importance of considering structural Y chromosome abnormalities in the evaluation of male infertility, even in individuals with otherwise normal pubertal development and secondary sexual characteristics.
Learning points
RCY is a rare but important genetic cause of male infertility and should be considered in the evaluation of severe oligozoospermia or azoospermia.
The clinical phenotype of RCY ranges from a normal male phenotype with infertility to phenotypic females with features of Turner syndrome. This is influenced by the presence or absence of Y-linked genes and the degree of 45,X mosaicism.
The presence of a 45,X cell line in individuals with RCY mosaicism has been associated with gonadal anomalies, particularly dysgenesis and cryptorchidism.
Topics
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References
30
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Li P
,
Dupont B
,
Hu Q
, et al.
The past, present, and future for constitutional ring chromosomes: a report of the international consortium for human ring chromosomes. HGG Adv 2022 3 100139. (https://doi.org/10.1016/j.xhgg.2022.100139)
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Maeda T
,
Ohno M
,
Ishibashi A
, et al.
Ring Y chromosome: 45, X/46, X, r (Y) chromosome mosaicism in a phenotypically normal male with azoospermia. Hum Genet 1976 34 99–102. (https://doi.org/10.1007/bf00284445)
[4]
Bertini V
,
Canale D
,
Bicocchi MP
, et al.
Mosaic ring Y chromosome in two normal healthy men with azoospermia. Fertil Steril 2005 84 1744.e1–1744.e4. (https://doi.org/10.1016/j.fertnstert.2005.06.034)
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Arnedo N
,
Nogués C
,
Bosch M
, et al.
Mitotic and meiotic behaviour of a naturally transmitted ring Y chromosome: reproductive risk evaluation. Hum Reprod 2005 20 462–468. (https://doi.org/10.1093/humrep/deh598)
[6]
Layman LC
,
Tho SP
,
Clark AD
, et al.
Phenotypic spectrum of 45,X/46,XY males with a ring Y chromosome and bilaterally descended testes. Fertil Steril 2009 91 791–797. (https://doi.org/10.1016/j.fertnstert.2007.12.078)
[7]
Dong Y
,
Yu X
,
Wang R
, et al.
45, X/46, X, r (Y)/46, X, dic r (Y) karyotype in an azoospermic male: a case report. Cytogenet Genome Res 2014 142 140–144. (https://doi.org/10.1159/000356467)
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Attia AM
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Yasien H
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[9]
Gisselsson D
,
Kristoffersson U
&
Giwercman A
. Ring Y chromosome in an azoospermic male with short stature: additional evidence for a distinct ring Y syndrome in Non-mosaic patients? Clin Genet 2003 64 519–521. (https://doi.org/10.1046/j.1399-0004.2003.00173.x)
[10]
Tzancheva M
,
Kaneva R
,
Kumanov P
, et al.
Two male patients with ring Y: definition of an interval in Yq contributing to Turner syndrome. J Med Genet 1999 36 549–553. (https://doi.org/10.1136/jmg.36.7.549)
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Taillemite JL
,
van den Akker J
,
Portnoi MF
, et al.
A case of ring Y chromosome. Hum Genet 1978 42 89–91. (https://doi.org/10.1007/bf00291630)
[12]
Wegner RD
,
Scherer G
,
Pohlschmidt M
, et al.
Ring Y chromosome: cytogenetic and molecular characterization. Clin Genet 1992 42 71–75. (https://doi.org/10.1111/j.1399-0004.1992.tb03142.x)
[13]
Henegariu O
,
Pescovitz OH
,
Vance GH
, et al.
A case with mosaic di-tetra-and octacentric ring Y chromosomes. Am J Med Genet 1997 71 426–429. (https://doi.org/10.1002/(sici)1096-8628(19970905)71:4<426::aid-ajmg10>3.3.co;2-9)
[14]
Khudr G
&
B Kurt
. Y ring chromosome associated with gonadoblastoma in situ. Obstet Gynecol 1973 41 897–901.
[15]
Bofinger MK
,
Needham DF
,
Saldana LR
, et al.
45,X/46,X,r(Y) karyotype transmitted by father to son after intracytoplasmic sperm injection for oligospermia. A case report. J Reprod Med 1999 44 645–648.
[16]
Li P
,
Dupont B
,
Hu Q
, et al.
The past, present, and future for constitutional ring chromosomes: a report of the international consortium for human ring chromosomes. HGG Adv 2022 3 100139. (https://doi.org/10.1016/j.xhgg.2022.100139)
[17]
DuPont BR
. Ring chromosome Y. In Human Ring Chromosomes: A Practical Guide for Clinicians and Families, pp 347–352. Eds
P Li
&
T Liehr
. Cham: Springer International Publishing, 2024. (https://doi.org/10.1007/978-3-031-47530-6)
[18]
Maeda T
,
Ohno M
,
Ishibashi A
, et al.
Ring Y chromosome: 45, X/46, X, r (Y) chromosome mosaicism in a phenotypically normal male with azoospermia. Hum Genet 1976 34 99–102. (https://doi.org/10.1007/bf00284445)
[19]
Bertini V
,
Canale D
,
Bicocchi MP
, et al.
Mosaic ring Y chromosome in two normal healthy men with azoospermia. Fertil Steril 2005 84 1744.e1–1744.e4. (https://doi.org/10.1016/j.fertnstert.2005.06.034)
[20]
Arnedo N
,
Nogués C
,
Bosch M
, et al.
Mitotic and meiotic behaviour of a naturally transmitted ring Y chromosome: reproductive risk evaluation. Hum Reprod 2005 20 462–468. (https://doi.org/10.1093/humrep/deh598)
[21]
Layman LC
,
Tho SP
,
Clark AD
, et al.
Phenotypic spectrum of 45,X/46,XY males with a ring Y chromosome and bilaterally descended testes. Fertil Steril 2009 91 791–797. (https://doi.org/10.1016/j.fertnstert.2007.12.078)
[22]
Dong Y
,
Yu X
,
Wang R
, et al.
45, X/46, X, r (Y)/46, X, dic r (Y) karyotype in an azoospermic male: a case report. Cytogenet Genome Res 2014 142 140–144. (https://doi.org/10.1159/000356467)
[23]
Attia AM
&
Yasien H
. Ring Y chromosome, review and case report. Int J Dis Disord 2013 1 001–006.
[24]
Gisselsson D
,
Kristoffersson U
&
Giwercman A
. Ring Y chromosome in an azoospermic male with short stature: additional evidence for a distinct ring Y syndrome in Non-mosaic patients? Clin Genet 2003 64 519–521. (https://doi.org/10.1046/j.1399-0004.2003.00173.x)
[25]
Tzancheva M
,
Kaneva R
,
Kumanov P
, et al.
Two male patients with ring Y: definition of an interval in Yq contributing to Turner syndrome. J Med Genet 1999 36 549–553. (https://doi.org/10.1136/jmg.36.7.549)
[26]
Taillemite JL
,
van den Akker J
,
Portnoi MF
, et al.
A case of ring Y chromosome. Hum Genet 1978 42 89–91. (https://doi.org/10.1007/bf00291630)
[27]
Wegner RD
,
Scherer G
,
Pohlschmidt M
, et al.
Ring Y chromosome: cytogenetic and molecular characterization. Clin Genet 1992 42 71–75. (https://doi.org/10.1111/j.1399-0004.1992.tb03142.x)
[28]
Henegariu O
,
Pescovitz OH
,
Vance GH
, et al.
A case with mosaic di-tetra-and octacentric ring Y chromosomes. Am J Med Genet 1997 71 426–429. (https://doi.org/10.1002/(sici)1096-8628(19970905)71:4<426::aid-ajmg10>3.3.co;2-9)
[29]
Khudr G
&
B Kurt
. Y ring chromosome associated with gonadoblastoma in situ. Obstet Gynecol 1973 41 897–901.
[30]
Bofinger MK
,
Needham DF
,
Saldana LR
, et al.
45,X/46,X,r(Y) karyotype transmitted by father to son after intracytoplasmic sperm injection for oligospermia. A case report. J Reprod Med 1999 44 645–648.
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Citations
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References
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- Published
- Oct 01, 2025
- Vol/Issue
- 2025(4)
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Authors
Cite This Article
Serena Chong, Christopher A Muir (2025). Ring Y chromosome as an unusual cause of severe oligozoospermia. Endocrinology, Diabetes & Metabolism Case Reports, 2025(4). https://doi.org/10.1530/edm-25-0113
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