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Rogers MJ. Y chromosome copy number variation and its effects on fertility and other health factors: a review. Transl Androl Urol 2021; 10:1373-1382. [PMID: 33850773 PMCID: PMC8039628 DOI: 10.21037/tau.2020.04.06] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The Y chromosome is essential for testis development and spermatogenesis. It is a chromosome with the lowest gene density owing to its medium size but paucity of coding genes. The Y chromosome is unique in that the majority of its structure is highly repetitive sequences, with the majority of these limited genes occurring in 9 amplionic sequences throughout the chromosome. The repetitive nature has its benefits as it can be protective against gene loss over many generations, but it can also predispose the Y chromosome to having wide variations of the number of gene copies present in these repeated sequences. This is known as copy number variation. Copy number variation is not unique to the Y chromosome but copy number variation is a well-known cause of male infertility and having effects on spermatogenesis. This is most commonly seen as deletions of the AZF sequences on the Y chromosome. However, there are other implications for copy number variation beyond just the AZF deletions that can affect spermatogenesis and potentially have other health implications. Copy number variations of TSPY1, DAZ, CDY1, RBMY1, the DYZ1 array, along with minor deletions of gr/gr, b1/b3, and b2/b3 have all be implicated in affecting spermatogenesis. UTY copy number variations have been implicated in risk for cardiovascular disease, and other deletions within gr/gr and the AZF sequences have been implicated in cancer and neuropsychiatric diseases. This review sets out to describe the Y chromosome and unique susceptibility to copy number variation and then to examine how this growing body of research impacts spermatogenesis and other health factors.
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Affiliation(s)
- Marc J Rogers
- Department of Urology, Medical University of South Carolina, Charleston, SC, USA
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New insights into the genetics of spermatogenic failure: a review of the literature. Hum Genet 2019; 138:125-140. [PMID: 30656449 DOI: 10.1007/s00439-019-01974-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Accepted: 01/09/2019] [Indexed: 12/23/2022]
Abstract
Genetic anomalies are known to affect about 15% of infertile patients with azoospermia or severe oligozoospermia. Despite a throughout diagnostic work-up, in up to the 72% of the male partners of infertile couples, no etiological factor can be found; hence, the cause of infertility remains unclear. Recently, several novel genetic causes of spermatogenic failure (SPGF) have been described. The aim of this review was to collect all the available evidence of SPGF genetics, matching data from in-vitro and animal models with those in human beings to provide a comprehensive and updated overview of the genes capable of affecting spermatogenesis. By reviewing the literature, we provided a list of 60 candidate genes for SPGF. Their investigation by Next Generation Sequencing in large cohorts of patients with apparently idiopathic infertility would provide new interesting data about their racial- and ethnic-related prevalence in infertile patients, likely raising the diagnostic yields. We propose a phenotype-based approach to identify the genes to look for.
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Colaco S, Modi D. Genetics of the human Y chromosome and its association with male infertility. Reprod Biol Endocrinol 2018; 16:14. [PMID: 29454353 PMCID: PMC5816366 DOI: 10.1186/s12958-018-0330-5] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Accepted: 02/06/2018] [Indexed: 12/12/2022] Open
Abstract
The human Y chromosome harbors genes that are responsible for testis development and also for initiation and maintenance of spermatogenesis in adulthood. The long arm of the Y chromosome (Yq) contains many ampliconic and palindromic sequences making it predisposed to self-recombination during spermatogenesis and hence susceptible to intra-chromosomal deletions. Such deletions lead to copy number variation in genes of the Y chromosome resulting in male infertility. Three common Yq deletions that recur in infertile males are termed as AZF (Azoospermia Factor) microdeletions viz. AZFa, AZFb and AZFc. As estimated from data of nearly 40,000 Y chromosomes, the global prevalence of Yq microdeletions is 7.5% in infertile males; however the European infertile men are less susceptible to Yq microdeletions, the highest prevalence is in Americans and East Asian infertile men. In addition, partial deletions of the AZFc locus have been associated with infertility but the effect seems to be ethnicity dependent. Analysis of > 17,000 Y chromosomes from fertile and infertile men has revealed an association of gr/gr deletion with male infertility in Caucasians and Mongolian men, while the b2/b3 deletion is associated with male infertility in African and Dravidian men. Clinically, the screening for Yq microdeletions would aid the clinician in determining the cause of male infertility and decide a rational management strategy for the patient. As these deletions are transmitted to 100% of male offspring born through assisted reproduction, testing of Yq deletions will allow the couples to make an informed choice regarding the perpetuation of male infertility in future generations. With the emerging data on association of Yq deletions with testicular cancers and neuropsychiatric conditions long term follow-up data is urgently needed for infertile men harboring Yq deletions. If found so, the information will change the current the perspective of androgenetics from infertility and might have broad implication in men health.
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Affiliation(s)
- Stacy Colaco
- Department of Molecular and Cellular Biology, ICMR-National Institute for Research in Reproductive Health, JM Street, Parel, Mumbai, Maharashtra, 400012, India
| | - Deepak Modi
- Department of Molecular and Cellular Biology, ICMR-National Institute for Research in Reproductive Health, JM Street, Parel, Mumbai, Maharashtra, 400012, India.
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Abstract
Men with severe oligospermia (<5 million sperm/mL ejaculate fluid) or azoospermia should receive genetic testing to clarify etiology of male infertility prior to treatment. Categorization by obstructive azoospermia (OA) or non-obstructive azoospermia (NOA) is critical since genetic testing differs for the former with normal testicular function, testicular volume (~20 mL), and follicle-stimulating hormone (FSH) (1-8 IU/mL) when compared to the latter with small, soft testes and increased FSH. History and physician examination along with laboratory testing (following appropriate genetic counseling) is critical to accurate selection of genetic testing appropriate for azoospermia due to primary testicular failure as compared with congenital hypogonadotropic hypogonadism (HH). Genetic testing options include cystic fibrosis transmembrane conductance regulator (CFTR) testing for men with congenital absence of the vas, while karyotype, Y chromosome microdeletions (YCMD), and other specific genetic tests may be warranted depending on the clinical context of severe oligospermia or NOA. The results of genetic testing guide management options. The most recent techniques for genetic analysis, including sperm microRNA (miRNA) and epigenetics, are forming the foundation for future genetic diagnosis and therapeutic targets in male infertility.
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Affiliation(s)
- Matthew S Wosnitzer
- Male Reproductive Medicine and Microsurgery, Instructor and Fellow. Department of Urology and Institute for Reproductive Medicine, Weill Cornell Medical College of Cornell University, 525 East 68 Street, New York, NY 10065, USA
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Wang RX, Fu C, Yang YP, Han RR, Dong Y, Dai RL, Liu RZ. Male infertility in China: laboratory finding for AZF microdeletions and chromosomal abnormalities in infertile men from Northeastern China. J Assist Reprod Genet 2010; 27:391-6. [PMID: 20425140 DOI: 10.1007/s10815-010-9420-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Accepted: 04/12/2010] [Indexed: 11/26/2022] Open
Abstract
PURPOSES To investigate the frequencies of AZF microdeletions and chromosomal abnormalities in infertile men from Northeastern China. Moreover, to compare the prevalence of these abnormalities with other countries and regions in the world. METHODS 305 infertile men were enrolled. A complete semen analysis and reproductive hormones were measured according to standard methods. Multiplex polymerase chain reaction (PCR) amplification using nine specific sequence-tagged sites (STS) were used to detect AZF microdeletions. Karyotype analyses were performed on peripheral blood lymphocytes with standard G-banding. RESULTS Of the 305 infertile men, 28 (9.2%) had AZF microdeletions and 26 (8.5%) had chromosomal abnormalities. The most frequent microdeletions were in the AZFc+d, followed by AZFc, AZFb+c+d and AZFa. A total of 19 patients (82.6%) had Klinefelter's syndrome (47, XXY) in the azoospermic group. CONCLUSIONS The freqencies of AZF microdeletions and chromosomal abnormalities in infertile men from Northeastern China were comparable with infertile men from other countries and regions. However, there was a slightly higher prevalence rate of AZF microdeletions in oligozoospermic patients than reported in previous studies.
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Affiliation(s)
- Rui-Xue Wang
- Center for Reproductive Medicine, First Hospital, Jilin University, Changchun, China
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Rozé V, Bresson JL, Fellmann F. Quantitative PCR technique for the identification of microrearrangements of the AZFc region. J Assist Reprod Genet 2007; 24:241-8. [PMID: 17410421 PMCID: PMC3454972 DOI: 10.1007/s10815-006-9055-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Accepted: 06/28/2006] [Indexed: 11/30/2022] Open
Abstract
PURPOSE The AZFc region spans about 3.5 Mb and contains many amplicons causing recombination events. Several papers have reported the occurrence of AZFc partial deletions resulting from non allelic homologous recombination (NAHR) ("gr-gr", "b1-b3" or "b2-b3" deletions), particularly in infertile patients. DAZ genes are present in 4 copies and rearrangements involve a modification of the number of DAZ genes. METHODS In addition to STS plus/minus PCR, we developed a quantitative technique using real time PCR (Q-PCR) to determine the number of DAZ genes. Fourteen DNA controls were selected to validate the use of Q-PCR to detect AZFc microrearrangements, and sperm DNA samples from 30 fertile men were studied. RESULTS Rearrangements of 14 controls were well identified with Q-PCR, and 2 AZFc partial deletions were detected in fertile men (1 "gr-gr" and 1 "b2-b3"). CONCLUSION Q-PCR represents a well-adapted method to detect microrearrangements of the Y-chromosome, complementary to STS analysis.
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Affiliation(s)
- Virginie Rozé
- EA MENRT 3185 Génétique et Reproduction - IFR133 IBCT, Faculté de Médecine et de Pharmacie, Besançon, France.
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Bor P, Hindkjaer J, Kølvraa S, Rossen P, von der Maase H, Jørgensen TM, Sørensen VT, Eiberg H, Ingerslev HJ. Screening for Y microdeletions in men with testicular cancer and undescended testis. J Assist Reprod Genet 2006; 23:41-5. [PMID: 16550456 PMCID: PMC3455431 DOI: 10.1007/s10815-005-9001-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Accepted: 09/15/2005] [Indexed: 10/24/2022] Open
Abstract
PURPOSE To investigate a possible association between testicular cancer or undescended testis and Y microdeletions. METHODS It was designed as a retrospective clinical study. A total of 225 men with testicular cancer or undescended testis were included to study. Fertile men (n = 200) were investigated as a control. Genomic DNA, which was extracted from blood samples were investigated with a fluorescent multiplex PCR protocol for screening for Y microdeletions. RESULTS A single STS missing was found in eight men; one from the control group (sY153), seven from the patients group. The positive cases showed a single STS missing of marker sY153 and sY139 in testicular cancer (6/185) and undescended testis (1/40) patients, respectively. CONCLUSIONS Since no contiguous, real Y microdeletions were found in the study population, it seems that Y microdeletions are not a likely common etiological cause of poor spermatogenesis in testicular cancer and undescended testis. However, it remains to be determined whether men having a single STS missing have a risk of developing testis cancer or having undescended testis.
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Zuccarello D, Morini E, Douzgou S, Ferlin A, Pizzuti A, Salpietro DC, Foresta C, Dallapiccola B. Preliminary data suggest that mutations in the CgRP pathway are not involved in human sporadic cryptorchidism. J Endocrinol Invest 2004; 27:760-4. [PMID: 15636430 DOI: 10.1007/bf03347519] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In testicular descent to the scrotum, a multistep process, many anatomical and hormonal factors play a role. Cryptorchidism occurs in about 1-2% of males and may cause secondary degeneration of the testes. Animal models have shown that abnormalities, in the calcitonin gene-related peptide (CgRP) activity, could be relevant in the pathogenesis of cryptorchidism. We performed a mutation screening by PCR exon amplification, single-strand conformation polymorphism (SSCP) and sequencing in four candidate genes, CgRPs (alphaCgRP, betaCgRP), their receptor (CgRPR) and the receptor component protein (CgRP-RCP), in 90 selected cases of idiopathic unilateral or bilateral cryptorchidism. Mutation screening of the coding regions and intron-exon boundaries revealed some polymorphic variants but no pathogenic sequence changes. These preliminary data suggest that these genes are not major factors for cryptorchidism in humans.
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Affiliation(s)
- D Zuccarello
- Department of Molecular Medicine and Pathology, University La Sapienza, Rome, Italy
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Ferlin A, Moro E, Rossi A, Dallapiccola B, Foresta C. The human Y chromosome's azoospermia factor b (AZFb) region: sequence, structure, and deletion analysis in infertile men. J Med Genet 2003; 40:18-24. [PMID: 12525536 PMCID: PMC1735253 DOI: 10.1136/jmg.40.1.18] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Microdeletions of the Y chromosome long arm are the most common mutations in infertile males, where they involve one or more "azoospermia factors" (AZFa, b, and c). Understanding of the AZF structure and gene content and mapping of the deletion breakpoints in infertile men are still incomplete. We have assembled a complete 4.3 Mb map of AZFb and surrounding regions by means of 38 BAC clones. The proximal part of AZFb consists of large repeated sequences organised in palindromes, but most of it is single copy sequence. A number of known and novel genes and gene families map in this interval, and most of them are testis specific or have testis specific transcripts. STS mapping allowed us to identify four severely infertile subjects with a deletion in AZFb with similar breakpoints, therefore suggesting a common deletion mechanism. This deletion includes at least five single copy genes and two duplicated genes, but does not remove the historical AZFb candidate gene RBMY1. These data suggest that other genes in AZFb may have important roles in spermatogenesis. We had no evidence for homologous recombination between large repeats as a possible deletion mechanism, as shown for AZFa and AZFc. However, identical sequences in AZFb and AZFc exist, and this finding could explain deletions found in these regions.
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Affiliation(s)
- A Ferlin
- University of Padova, Department of Medical and Surgical Sciences, Clinica Medica 3, Centre for Male Gamete Cryopreservation, Via Ospedale 105, 35128 Padova, Italy
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Foresta C, Moro E, Rossi A, Rossato M, Garolla A, Ferlin A. Role of the AZFa candidate genes in male infertility. J Endocrinol Invest 2000; 23:646-51. [PMID: 11097428 DOI: 10.1007/bf03343788] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The AZFa region on the Y-chromosome long arm has been recently assembled in a complete sequence map contained in a contig and shown to span more than 1 Mb. It contains three genes, USP9Y, DBY and UTY, but only the former two can be at present considered candidate genes for the infertile phenotype associated with deletion of this interval. These genes have X-homologues and are expressed in many tissues, even if DBY has a shorter transcript expressed in the testis only, strengthening its role in spermatogenesis. Only few patients with gene-specific deletion have been reported and a clear genotype-phenotype relation is still lacking. While deletions or even smaller mutations in USP9Y seem to be associated with a testicular phenotype of severe hypospermatogenesis, patients with deletions of DBY may present both Sertoli cell-only syndrome and severe hypospermatogenesis. On the contrary, the phenotype of patients with deletion of both USP9Y and DBY seem to be invariably azoospermia with a testicular histology of Sertoli cell-only.
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Affiliation(s)
- C Foresta
- Department of Medical and Surgical Sciences, University of Padova, Italy.
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Paracchini S, Stuppia L, Gatta V, Palka G, Moro E, Foresta C, Mengua L, Oliva R, Ballescà JL, Kremer JA, van Golde RJ, Tuerlings JH, Hargreave T, Ross A, Cooke H, Huellen K, Vogt PH, Tyler-Smith C. Y-chromosomal DNA haplotypes in infertile European males carrying Y-microdeletions. J Endocrinol Invest 2000; 23:671-6. [PMID: 11097432 DOI: 10.1007/bf03343792] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have determined Y-chromosomal DNA haplotypes in 73 infertile European males carrying Y microdeletions and compared them with the haplotypes of 299 infertile males lacking microdeletions. Chromosomes were typed with a set of 11 binary Y markers, which identified 8 haplogroups in the sample. Haplogroup frequencies were compared between 3 microdeletion classes and the non-deleted infertile males. Deletions arise on many different haplotypic backgrounds. No statistically significant differences in frequency were seen, although the small number of AZFa deletions lay predominantly on one branch of the Y haplotype tree.
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Affiliation(s)
- S Paracchini
- Department of Biochemistry, University of Oxford, UK
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