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Liu P, Lacaria M, Zhang F, Withers M, Hastings P, Lupski J. Frequency of nonallelic homologous recombination is correlated with length of homology: evidence that ectopic synapsis precedes ectopic crossing-over. Am J Hum Genet 2011; 89:580-8. [PMID: 21981782 DOI: 10.1016/j.ajhg.2011.09.009] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 09/14/2011] [Accepted: 09/15/2011] [Indexed: 10/16/2022] Open
Abstract
Genomic disorders constitute a class of diseases that are associated with DNA rearrangements resulting from region-specific genome instability, that is, genome architecture incites genome instability. Nonallelic homologous recombination (NAHR) or crossing-over in meiosis between sequences that are not in allelic positions (i.e., paralogous sequences) can result in recurrent deletions or duplications causing genomic disorders. Previous studies of NAHR have focused on description of the phenomenon, but it remains unclear how NAHR occurs during meiosis and what factors determine its frequency. Here we assembled two patient cohorts with reciprocal genomic disorders; deletion associated Smith-Magenis syndrome and duplication associated Potocki-Lupski syndrome. By assessing the full spectrum of rearrangement types from the two cohorts, we find that complex rearrangements (those with more than one breakpoint) are more prevalent in copy-number gains (17.7%) than in copy-number losses (2.3%); an observation that supports a role for replicative mechanisms in complex rearrangement formation. Interestingly, for NAHR-mediated recurrent rearrangements, we show that crossover frequency is positively associated with the flanking low-copy repeat (LCR) length and inversely influenced by the inter-LCR distance. To explain this, we propose that the probability of ectopic chromosome synapsis increases with increased LCR length, and that ectopic synapsis is a necessary precursor to ectopic crossing-over.
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Lu C, Zhang F, Yang H, Xu M, Du G, Wu W, An Y, Qin Y, Ji G, Han X, Gu A, Xia Y, Song L, Wang S, Jin L, Wang X. Additional genomic duplications in AZFc underlie the b2/b3 deletion-associated risk of spermatogenic impairment in Han Chinese population. Hum Mol Genet 2011; 20:4411-21. [PMID: 21852246 DOI: 10.1093/hmg/ddr369] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The azoospermia factor c (AZFc) region on the Y chromosome is a genetically dynamic locus in the human genome. Numerous genomic rearrangements, including deletion, duplication and inversion, have been identified in AZFc. The complete deletion of AZFc can cause spermatogenic impairment. However, the roles of partial AZFc deletions (e.g. b2/b3 deletion) in spermatogenesis are controversial and variable among human populations. Secondary duplication has been hypothesized to be a compensatory factor for partial AZFc deletions. To further study genomic duplications in AZFc as a potential genetic modifier underlying the phenotypic variations of partial AZFc deletions in spermatogenesis, we conducted comprehensive molecular analyses in 711 idiopathic infertile men and 390 healthy controls. Unexpectedly, we found that additional AZFc duplications accompanying the b2/b3 deletion, instead of the b2/b3 deletion alone, led to the b2/b3 deletion-associated risk of spermatogenic impairment previously reported in Han Chinese population. In addition, partial AZFc duplication also rendered a risk factor in the non-deletion patients. DAZ is a multi-copy AZFc gene (DAZ1-DAZ4) implicated in spermatogenesis. Genetic variations do exist between DAZ copies. Intriguingly, we found that the DAZ1/2 cluster was the main duplicated copies in the partial AZFc duplications associated with spermatogenic impairment, suggesting a potential different role of spermatogenesis between DAZ copies. Our findings demonstrated that additional AZFc duplications did not compensate but convey the susceptibility of the b2/b3 deletion to spermatogenic impairment in the tested population. Notably, genomic duplications and deletions in AZFc deserve comprehensive investigations to uncover spermatogenic roles of the AZFc region.
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Affiliation(s)
- Chuncheng Lu
- Key Laboratory of Reproductive Medicine, School of Public Health, Institute of Toxicology, Nanjing Medical University, Nanjing 210029, China
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Gu A, Ji G, Long Y, Zhou Y, Shi X, Song L, Wang X. Assessment of an Association between an Aryl Hydrocarbon Receptor Gene (AHR) Polymorphism and Risk of Male Infertility. Toxicol Sci 2011; 122:415-21. [DOI: 10.1093/toxsci/kfr137] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Krausz C, Chianese C, Giachini C, Guarducci E, Laface I, Forti G. The Y chromosome-linked copy number variations and male fertility. J Endocrinol Invest 2011; 34:376-82. [PMID: 21422806 DOI: 10.1007/bf03347463] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Since the first definition of the AZoospermia Factor (AZF) regions, the Y chromosome has become an important target for studies aimed to identify genetic factors involved in male infertility. This chromosome is enriched with genes expressed exclusively or prevalently in the testis and their absence or reduction of their dosage is associated with spermatogenic impairment. Due to its peculiar structure, full of repeated homologous sequences, the Y chromosome is predisposed to structural rearrangements, especially deletions/ duplications. This review discusses what is currently known about clinically relevant Y chromosome structural variations in male fertility, mainly focusing on copy number variations (CNVs). These CNVs include classical AZF deletions, gr/gr deletion and TSPY1 CNV. AZF deletions are in a clear-cut causeeffect relationship with spermatogenic failure and they also have a prognostic value for testis biopsy. gr/gr deletion represents the unique example in andrology of a proven genetic risk factor, providing an eight-fold increased risk for oligozoospermia in the Italian population. Studies on TSPY1 CNV have opened new perspectives on the role of this gene in spermatogenic efficiency. Although studies on the Y chromosome have importantly contributed to the identification of new genetic causes and thus to the improvement of the diagnostic work-up for severe male factor infertility, there is still about 50% of infertile men in whom the etiology remains unknown. While searching for new genetic factors on other chromosomes, our work on the Y chromosome still needs to be completed, with special focus on the biological function of the Y genes.
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Affiliation(s)
- C Krausz
- Sexual Medicine and Andrology Unit, Department of Clinical Physiopathology, University of Florence, Florence 50139, Italy.
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55
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Carvalho CMB, Zhang F, Lupski JR. Structural variation of the human genome: mechanisms, assays, and role in male infertility. Syst Biol Reprod Med 2011; 57:3-16. [PMID: 21210740 DOI: 10.3109/19396368.2010.527427] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Genomic disorders are defined as diseases caused by rearrangements of the genome incited by a genomic architecture that conveys instability. Y-chromosome related dysfunctions such as male infertility are frequently associated with gross DNA rearrangements resulting from its peculiar genomic architecture. The Y-chromosome has evolved into a highly specialized chromosome to perform male functions, mainly spermatogenesis. Direct and inverted repeats, some of them palindromes with highly identical nucleotide sequences that can form DNA cruciform structures, characterize the genomic structure of the Y-chromosome long arm. Some particular Y chromosome genomic deletions can cause spermatogenic failure likely because of removal of one or more transcriptional units with a potential role in spermatogenesis. We describe mechanisms underlying the formation of human genomic rearrangements on autosomes and review Y-chromosome deletions associated with male infertility.
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Affiliation(s)
- Claudia M B Carvalho
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030-3498, USA
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Stahl PJ, Mielnik A, Margreiter M, Marean MB, Schlegel PN, Paduch DA. Diagnosis of the gr/gr Y chromosome microdeletion does not help in the treatment of infertile American men. J Urol 2010; 185:233-7. [PMID: 21074808 DOI: 10.1016/j.juro.2010.09.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2010] [Indexed: 11/17/2022]
Abstract
PURPOSE The phenotypic effects of the gr/gr partial azoospermia factor c deletion vary geographically and to our knowledge have not been reported in the American population. We evaluated the clinical characteristics of infertile American men with the gr/gr deletion. MATERIALS AND METHODS We retrospectively reviewed clinical data on 1,410 infertile men tested for the gr/gr deletion. We analyzed sperm concentration and the outcome of microdissection testicular sperm extraction with respect to gr/gr status. RESULTS We identified 73 men with gr/gr deletions, including 43 of 989 (4.3%) with azoospermia, 18 of 317 (5.7%) with severe oligospermia (less than 5 million sperm per ml), 6 of 61 (9.8%) with oligospermia (5 to less than 20 million sperm per ml) and 6 of 43 (14%) infertile men with normospermia (greater than 20 million sperm per ml). A gr/gr deletion correlated with higher sperm production. The gr/gr deletion rate was higher in men with normospermia than in those with a sperm concentration of less than 20 million and less than 5 million per ml (p = 0.021 and 0.006, respectively). Microdissection testicular sperm extraction was done in 22 azoospermic men with gr/gr deletions and sperm were retrieved in 14 (64%). This retrieval rate was similar to that at our center in men with idiopathic nonobstructive azoospermia (p = 0.13). CONCLUSIONS Diagnosis of the gr/gr deletion did not predict impaired sperm production in our patient population and did not appear to alter the prognosis for surgical sperm retrieval. Despite the established modulatory impact of the gr/gr deletion on sperm production in some populations at this time the clinical value of testing infertile American men for the gr/gr deletion is not clear.
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Affiliation(s)
- Peter J Stahl
- Department of Urology, Weill Cornell Medical College, New York, New York, USA.
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Stouffs K, Lissens W, Tournaye H, Haentjens P. What about gr/gr deletions and male infertility? Systematic review and meta-analysis. Hum Reprod Update 2010; 17:197-209. [PMID: 20959348 DOI: 10.1093/humupd/dmq046] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The impact of gr/gr deletions on male fertility is unclear. These partial deletions of the AZFc region of the Y chromosome have been detected more frequently in infertile patients. However, few individual studies have demonstrated a statistically significant association. This study aims to quantify the strength of association between gr/gr deletions and male infertility, and to explore potential sources of heterogeneity, including ethnicity and geographical location. METHODS Medline was searched up to 31 December 2009 for full articles investigating the prevalence of gr/gr deletions in infertile and control men. A pooled odds ratio (OR) was estimated by a random-effects model. Heterogeneity was assessed by the Cochran's Q test, and quantified by I(2) statistic. RESULTS A total of 18 case-control studies, including 6388 cases and 6011 controls, met our inclusion criteria and showed that gr/gr deletions were present in 6.86% of cases and 4.69% of controls. The association between gr/gr deletions and infertility was significant (P < 0.001), with a pooled random-effects OR of 1.76 (1.21-2.66) for infertile men versus normozoospermic controls (13 studies). The test for heterogeneity among studies yielded a Q test P = 0.089 with I(2) value of 37%, indicating moderate heterogeneity. The association between gr/gr deletions and infertility was dependent on ethnicity and geographic region. CONCLUSIONS Our meta-analysis comprising >12 000 men demonstrates that gr/gr deletions occur more frequently in infertile than control men. The association between gr/gr deletions and infertility varies according to ethnicity and geographic region, with an association reaching significance among Caucasian men, in Europe and the Western Pacific region.
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Affiliation(s)
- Katrien Stouffs
- Centre for Medical Genetics, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, Laarbeeklaan 101, Brussels, Belgium.
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Navarro-Costa P, Gonçalves J, Plancha CE. The AZFc region of the Y chromosome: at the crossroads between genetic diversity and male infertility. Hum Reprod Update 2010; 16:525-42. [PMID: 20304777 PMCID: PMC2918367 DOI: 10.1093/humupd/dmq005] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND The three azoospermia factor (AZF) regions of the Y chromosome represent genomic niches for spermatogenesis genes. Yet, the most distal region, AZFc, is a major generator of large-scale variation in the human genome. Determining to what extent this variability affects spermatogenesis is a highly contentious topic in human reproduction. METHODS In this review, an extensive characterization of the molecular mechanisms responsible for AZFc genotypical variation is undertaken. Such data are complemented with the assessment of the clinical consequences for male fertility imputable to the different AZFc variants. For this, a critical re-evaluation of 23 association studies was performed in order to extract unifying conclusions by curtailing methodological heterogeneities. RESULTS Intrachromosomal homologous recombination mechanisms, either crossover or non-crossover based, are the main drivers for AZFc genetic diversity. In particular, rearrangements affecting gene dosage are the most likely to introduce phenotypical disruptions in the spermatogenic profile. In the specific cases of partial AZFc deletions, both the actual existence and the severity of the spermatogenic defect are dependent on the evolutionary background of the Y chromosome. CONCLUSIONS AZFc is one of the most genetically dynamic regions in the human genome. This property may serve as counter against the genetic degeneracy associated with the lack of a meiotic partner. However, such strategy comes at a price: some rearrangements represent a risk factor or a de-facto causative agent of spermatogenic disruption. Interestingly, this precarious balance is modulated, among other yet unknown factors, by the evolutionary history of the Y chromosome.
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Affiliation(s)
- Paulo Navarro-Costa
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Lisboa, Portugal.
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O'Flynn O'Brien KL, Varghese AC, Agarwal A. The genetic causes of male factor infertility: a review. Fertil Steril 2010; 93:1-12. [PMID: 20103481 DOI: 10.1016/j.fertnstert.2009.10.045] [Citation(s) in RCA: 280] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 10/27/2009] [Accepted: 10/27/2009] [Indexed: 12/28/2022]
Abstract
OBJECTIVE To illustrate the necessity for an enhanced understanding of the genetic basis of male factor infertility, to present a comprehensive synopsis of these genetic elements, and to review techniques being utilized to produce new insights in fertility research. BACKGROUND Male factor infertility is a complex disorder that affects a large sector of the population; however, many of its etiologies are unknown. By elucidating the underlying genetic basis of infertile phenotypes, it may be possible to discover the causes of infertility and determine effective treatments for patients. METHOD(S) The PubMed database was consulted for the most relevant papers published in the last 3 years pertaining to male factor infertility using the keywords "genetics" and "male infertility." RESULT(S) Advances have been made in the characterization of the roles of specific genes, but further research is necessary before these results can be used as guidelines for diagnosing and treating male factor infertility. The accurate transmission of epigenetic information also has considerable influence on fertility in males and on the fertility of their offspring. CONCLUSION(S) Analysis of the genetic factors that impact male factor infertility will provide valuable insights into the creation of targeted treatments for patients and the determination of the causes of idiopathic infertility. Novel technologies that analyze the influence of genetics from a global perspective may lead to further developments in the understanding of the etiology of male factor infertility through the identification of specific infertile phenotype signatures.
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Affiliation(s)
- Katherine L O'Flynn O'Brien
- Center for Reproductive Medicine, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, Ohio 44195, USA
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60
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Zhu XB, Liu YL, Zhang W, Ping P, Cao XR, Liu Y, Huang YR, Li Z. Vertical transmission of the Yq AZFc microdeletion from father to son over two or three generations in infertile Han Chinese families. Asian J Androl 2009; 12:240-6. [PMID: 19966830 DOI: 10.1038/aja.2009.63] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
This study was carried out to analyze the vertical transmission of Yq AZFc microdeletions from father to son in infertile Han Chinese families to investigate genetic factors and family background affecting fertility status. The peripheral blood of infertile males in 19 Han families was extracted and screened with modified multiplex polymerase chain reaction (PCR). Family trees were drawn according to fertility status and clinical characteristics of the subjects. The vertical transmission of Yq AZFc microdeletions was detected in six cases of 19 investigated families (31.6%, 6/19). Although both fathers and sons showed a similar type of Yq AZFc deletion, the fathers were fertile, whereas the sons were infertile and showed severe oligozoospermia. The vertical transmission of Yq AZFc microdeletion from fertile fathers to infertile sons over generations is not rare. This has different effects on fertility status in fathers and sons in Han Chinese families. Both genetic factors and family background affect spermatogenetic phenotypes.
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Affiliation(s)
- Xiao-Bin Zhu
- Shanghai Human Sperm Bank, Renji Hospital, Shanghai Institute of Andrology, Shanghai Jiao Tong University School of Medicine, China
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Shaqalaih AJ, Abu Halima MS, Ashour MJ, Sharif FA. Screening for Y-chromosome microdeletions in a population of infertile males in the Gaza Strip. JOURNAL OF EXPERIMENTAL & CLINICAL ASSISTED REPRODUCTION 2009; 6:7. [PMID: 20485582 PMCID: PMC2868306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Infertility is an extraordinary public health problem in the Arab world, as it affects about 15% of couples seeking children. The male partner is responsible for infertility in approximately half of these cases. Classic microdeletions of the Y-chromosome involving the azoospermia factor (AZF) regions are known to be associated with spermatogenic impairment, and non-obstructive azoospermia must be differentiated on the basis of endocrine evaluation and testicular biopsy. Partial AZFc deletions remain controversial because there is no clear agreement regarding their role in spermatogenic failure. In the current study, 50 fertile males (controls) and 125 patients with primary idiopathic male infertility were studied in order to describe the frequency of Y-chromosome mirodeletions among male infertility patients in the Gaza Strip-Palestine area. No Y chromosome classical microdeletions could be detected in any of the 125 infertile men, suggesting that ethnic factors, genetic background, and Y chromosome haplogroups are key factors in such deletions. On the other hand, six gr/gr and one b1/b3 AZFc partial deletions were detected in the infertile population. The gr/gr deletion was also noted in relatives of four of the six patients with this deletion, and in one of the fertile controls. In conclusion, our study shows that the incidence of Y-chromosome microdeletions in our population is rare; these data suggest that other genetic, epigenetic, nutritional and/or local factors are responsible for impairments in semen parameters observed in this Gazan population. We further hypothesise that the gr/gr deletion is not associated with male infertility, at least in this sub-group.
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Affiliation(s)
| | - Masood S. Abu Halima
- Corresponding Author: Masood Abu Halima,
, P.O.Box 1425, Omar Mukhtar St. Gaza, Palestine, Tel: 00972 8 2820544, Fax: 00972 8 2865317, Cell phone: 00972 599 187785
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Stuppia L, Gatta V, Antonucci I, Giuliani R, Scioletti AP, Palka G. Genetic testing in couples undergoing assisted reproduction technique protocols. ACTA ACUST UNITED AC 2009; 3:571-83. [DOI: 10.1517/17530050902970986] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Lu C, Zhang J, Li Y, Xia Y, Zhang F, Wu B, Wu W, Ji G, Gu A, Wang S, Jin L, Wang X. The b2/b3 subdeletion shows higher risk of spermatogenic failure and higher frequency of complete AZFc deletion than the gr/gr subdeletion in a Chinese population. Hum Mol Genet 2009; 18:1122-30. [DOI: 10.1093/hmg/ddn427] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Zhang J, Li PQ, Yu QH, Chen HY, Li J, He YS. Development of a multiplex quantitative fluorescent PCR assay for identification of rearrangements in the AZFb and AZFc regions. Mol Hum Reprod 2008; 14:371-6. [PMID: 18445645 DOI: 10.1093/molehr/gan022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The azoospermia factor b (AZFb) and azoospermia factor c (AZFc) regions in the human Y chromosome consist of five palindromes constructed from six distinct families of amplicons and are prone to rearrangement. Partial deletion and duplication in the region can cause azoospermia or oligozoospermia and male infertility. The aim of the study was to establish a quantitative fluorescent PCR (QF-PCR) assay to classify AZFb and AZFc rearrangements. A single pair of fluorescent primers was designed to amplify simultaneously the amplicon in AZFc and the length-variant homologous sequences outside of the region as control. Since the copy number of the control sequences is fixed in the human genome, dosage of the target could be easily obtained through comparing the height of the fluorescent peaks between the target and the control after amplification with limited PCR cycles. Most types of rearrangements in AZFb and AZFc regions could be classified with QF-PCR containing four such primer pairs. Eleven types of rearrangement in AZFb and AZFc regions were well discriminated with QF-PCR. In conclusion, QF-PCR is a simple and reliable method to detect rearrangements in AZFb and AZFc.
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Affiliation(s)
- Jun Zhang
- Department of Anatomy, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong 510080, People's Republic of China
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66
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Stouffs K, Tournaye H, Van der Elst J, Haentjens P, Liebaers I, Lissens W. Do we need to search for gr/gr deletions in infertile men in a clinical setting? Hum Reprod 2008; 23:1193-9. [PMID: 18326516 DOI: 10.1093/humrep/den069] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Partial deletions of the AZFc region of the Y chromosome such as gr/gr deletions have been detected in infertile patients as well as in control groups. The impact of these gr/gr deletions on the etiology of male infertility remains unknown. In the present study, we investigated the presence of gr/gr deletions in Caucasian men. METHODS gr/gr deletions were analyzed by using markers sY1291, sY1191 and sY1197 and by investigating the presence of single nucleotide variants (SNV) in DAZ and CDY1 genes in patients with azoospermia (n = 44), cryptozoospermia (n = 51) or severe oligozoospermia (n = 92). Control groups consisted of men with normal spermatogenesis on testicular biopsy (n = 33), normozoospermia (n = 278) or proven fertility (n = 83). RESULTS We observed 20 gr/gr deletions, with eight in infertile patients (4.3%) and 12 in the control groups (3.0%), which was not significantly different. DAZ SNV analysis revealed eight different deletion patterns in patients and controls. CONCLUSIONS In the present study, no significant differences in the frequency of gr/gr deletions between different patient and control groups were observed. We concluded that the relationship between gr/gr deletions and male infertility remains unclear and that it is too early to systematically test for gr/gr deletions for infertile couples seeking assisted reproduction treatment.
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Affiliation(s)
- Katrien Stouffs
- Research Centre for Reproduction and Genetics, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Brussels, Belgium.
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Tüttelmann F, Rajpert-De Meyts E, Nieschlag E, Simoni M. Gene polymorphisms and male infertility--a meta-analysis and literature review. Reprod Biomed Online 2008; 15:643-58. [PMID: 18062861 DOI: 10.1016/s1472-6483(10)60531-7] [Citation(s) in RCA: 142] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Many genetic polymorphisms have been studied extensively to elucidate their role in the pathophysiology of male infertility. This article presents a review of the literature following a thorough search of PubMed, a compilation of meta-analyses of studies reporting an association with male fertility where the population(s) could be clearly identified as fertile and/or infertile, and a summary of all polymorphisms that have been investigated in single case-control studies to date. The meta-analyses revealed significant associations between polymorphism and male fertility only for AZF gr/gr deletions (OR 1.81, 1.46-2.24 CI, P<0.00001) and MTHFR 677C-->T (OR 1.39, 1.15-2.69 95% CI, P=0.0006) but not for POLG, DAZL, USP26 or FSHR. The influence of CAG repeat length in AR remains open and debated. Genes encoding nuclear proteins (PRM1/2, TNP1/2) and ER1 are possible candidates for further examination, while the role of TAF7L remains unclear. Polymorphisms in 16 other genes have been investigated in single studies, but the results remain doubtful due to often small and heterogeneous cohorts and in the absence of independent replications. The genetic studies performed so far emphasize the complexity of male infertility as a presumably polygenetic trait amended by environmental, lifestyle or occupational factors.
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Affiliation(s)
- Frank Tüttelmann
- Institute of Reproductive Medicine of the University, Domagkstrasse 11, D-48129 Münster, Germany
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68
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Underhill PA, Kivisild T. Use of Y Chromosome and Mitochondrial DNA Population Structure in Tracing Human Migrations. Annu Rev Genet 2007; 41:539-64. [PMID: 18076332 DOI: 10.1146/annurev.genet.41.110306.130407] [Citation(s) in RCA: 308] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Peter A. Underhill
- Department of Genetics, Stanford University School of Medicine, Stanford, California 94305-5120;
| | - Toomas Kivisild
- Leverhulme Center of Human Evolutionary Studies, University of Cambridge, Cambridge CB2 1QH, United Kingdom;
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Navarro-Costa P, Pereira L, Alves C, Gusmão L, Proença C, Marques-Vidal P, Rocha T, Correia SC, Jorge S, Neves A, Soares AP, Nunes J, Calhaz-Jorge C, Amorim A, Plancha CE, Gonçalves J. Characterizing partial AZFc deletions of the Y chromosome with amplicon-specific sequence markers. BMC Genomics 2007; 8:342. [PMID: 17903263 PMCID: PMC2151955 DOI: 10.1186/1471-2164-8-342] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Accepted: 09/28/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The AZFc region of the human Y chromosome is a highly recombinogenic locus containing multi-copy male fertility genes located in repeated DNA blocks (amplicons). These AZFc gene families exhibit slight sequence variations between copies which are considered to have functional relevance. Yet, partial AZFc deletions yield phenotypes ranging from normospermia to azoospermia, thwarting definite conclusions on their real impact on fertility. RESULTS The amplicon content of partial AZFc deletion products was characterized with novel amplicon-specific sequence markers. Data indicate that partial AZFc deletions are a male infertility risk [odds ratio: 5.6 (95% CI: 1.6-30.1)] and although high diversity of partial deletion products and sequence conversion profiles were recorded, the AZFc marker profiles detected in fertile men were also observed in infertile men. Additionally, the assessment of rearrangement recurrence by Y-lineage analysis indicated that while partial AZFc deletions occurred in highly diverse samples, haplotype diversity was minimal in fertile men sharing identical marker profiles. CONCLUSION Although partial AZFc deletion products are highly heterogeneous in terms of amplicon content, this plasticity is not sufficient to account for the observed phenotypical variance. The lack of causative association between the deletion of specific gene copies and infertility suggests that AZFc gene content might be part of a multifactorial network, with Y-lineage evolution emerging as a possible phenotype modulator.
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Affiliation(s)
- Paulo Navarro-Costa
- Centro de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, 1649-016 Lisboa, Portugal
- Unidade de Biologia da Reprodução, Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, 1649-028 Lisboa, Portugal
| | - Luísa Pereira
- IPATIMUP – Instituto de Patologia e Imunologia Molecular da Universidade do Porto, 4200-465 Porto, Portugal
- Faculdade de Medicina da Universidade do Porto, 4200-319 Porto, Portugal
| | - Cíntia Alves
- IPATIMUP – Instituto de Patologia e Imunologia Molecular da Universidade do Porto, 4200-465 Porto, Portugal
| | - Leonor Gusmão
- IPATIMUP – Instituto de Patologia e Imunologia Molecular da Universidade do Porto, 4200-465 Porto, Portugal
| | - Carmen Proença
- Centro de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, 1649-016 Lisboa, Portugal
| | - Pedro Marques-Vidal
- Unidade de Nutrição e Metabolismo, Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, 1649-028 Lisboa, Portugal
| | - Tiago Rocha
- Unidade de Medicina da Reprodução, Maternidade Dr. Alfredo da Costa, 1069-089 Lisboa, Portugal
| | - Sónia C Correia
- Unidade de Medicina da Reprodução, Maternidade Dr. Alfredo da Costa, 1069-089 Lisboa, Portugal
| | - Sónia Jorge
- Unidade de Medicina da Reprodução, Maternidade Dr. Alfredo da Costa, 1069-089 Lisboa, Portugal
| | - António Neves
- Unidade de Medicina da Reprodução, Maternidade Dr. Alfredo da Costa, 1069-089 Lisboa, Portugal
| | - Ana P Soares
- Unidade Pluridisciplinar de Reprodução Humana, Hospital de Santa Maria, 1649-028 Lisboa, Portugal
| | - Joaquim Nunes
- Unidade Pluridisciplinar de Reprodução Humana, Hospital de Santa Maria, 1649-028 Lisboa, Portugal
| | - Carlos Calhaz-Jorge
- Unidade Pluridisciplinar de Reprodução Humana, Hospital de Santa Maria, 1649-028 Lisboa, Portugal
| | - António Amorim
- IPATIMUP – Instituto de Patologia e Imunologia Molecular da Universidade do Porto, 4200-465 Porto, Portugal
- Faculdade de Ciências da Universidade do Porto, 4169-007 Porto, Portugal
| | - Carlos E Plancha
- Unidade de Biologia da Reprodução, Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, 1649-028 Lisboa, Portugal
| | - João Gonçalves
- Centro de Genética Humana, Instituto Nacional de Saúde Dr. Ricardo Jorge, 1649-016 Lisboa, Portugal
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