The association of gr/gr deletion in the Y chromosome and impaired spermatogenesis in Bulgarian males: a pilot study

Levkova, Mariya; Chervenkov, Trifon; Angelova, Lyudmila

doi:10.1186/s43043-020-00020-9

Cited by 4 publications

(4 citation statements)

References 24 publications

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“…This pattern has previously been reported as the most common AZFc rearrangement and has been observed in several Y chromosome haplogroups as a consequence of multiple independent recombinational events 9 . Based on previous studies, men carrying the gr/gr primary duplication are at increased risk for infertility in Asia 14 while this association seems to be not statistically significant among European populations 38 , 39 .…”

Section: Resultsmentioning

confidence: 94%

High incidence of AZF duplications in clan-structured Iranian populations detected through Y chromosome sequencing read depth analysis

Hajiesmaeil,

Ravasini,

Risi

et al. 2023

Sci Rep

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The ampliconic region of the human Y chromosome consists of large duplicated sequences that can undergo non-allelic homologous recombination (NAHR), resulting in structural rearrangements that may cause infertility, especially when they occur in the azoospermia factor b/c (AZFb/c) region. Although AZF duplications have long been neglected due to the technical limitations of STS-based studies that focused mainly on deletions, recent next generation sequencing (NGS) technologies provided evidence for their importance in fertility. In this study, a NGS read depth approach was used to detect AZFb/c rearrangements in 87 Iranians from different ethnic groups. The duplication frequency in Iran proved to be twice as high as in the "1000 Genomes" dataset. Interestingly, most duplications were found in patrilineal ethnic groups, possibly as a consequence of their lower male effective population size which can counteract negative selection. Moreover, we found a large 8.0 Mb duplication, resulting in a fourfold increase in the copy number of AZFc genes, which to our knowledge is the largest duplication ever reported in this region. Overall, our results suggest that it is important to consider not only AZF deletions but also duplications to investigate the causes of male infertility, especially in patrilineal clan-based populations.

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Section: Resultsmentioning

confidence: 94%

High incidence of AZF duplications in clan-structured Iranian populations detected through Y chromosome sequencing read depth analysis

Hajiesmaeil,

Ravasini,

Risi

et al. 2023

Sci Rep

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“…Some studies have shown a significant association between partial AZFc deletions and spermatogenic failures 8,15,17,18 . However, there are also studies which deny its role and find no correlation between the partial AZFc deletion and impaired spermatogenesis 10,19,20 .…”

Section: Discussionmentioning

confidence: 99%

“…The deletion, however, does not remove all of the genes found in the AZFc locus, but it does reduce the number of DAZ genes by removing two of them 8 . Since 2003, researchers in various countries have been investigating the potential impact of the gr/gr deletion on spermatogenesis but their findings remain controversial 9,10 .…”

Section: Lack Of Association Between Partial Y Chromosome Azfc-gr/gr ...mentioning

confidence: 99%

Lack of Association Between Partial Y chromosome AZFc-gr/gr Deletions and Male Infertility

Abdulwahid,

Al-Attar

2023

Bio. Med. Tar. Jour.

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A microdeletion in the azoospermia factor (AZF) region of the human Y chromosome long arm is the second most common genetic factor causing male infertility and spermatogenetic failure. The current study aimed to evaluate the occurrence of AZFc-partial gr/gr deletions in a sample of 260 infertile azoospermia and 40 fertile men as a control group from the Kurdish community using the gel-based PCR technique. To understand whether these deletions were associated with their fertility problems. Two pairs of gr/gr primers (sY1291and sY1191) and a primer of Hetero-chromatin sY160-F were used for screening for gr/gr deletion in a single PCR reaction according to EAA and EMQN protocol. Based on the results of this study, no AZF/c gr/gr deletions were found in either the infertile or fertile participants. Therefore, this finding confirms the concept that these AZFc gr/gr partial deletions are improbable to have an important impact on infertility, and the hereditary risk associated with these partial deletions is much reduced compared to deletions that affect the entire AZFc region.

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“… 60 Contrarily, a 2020 study of 30 Bulgarian men with severe oligospermia (>0–5 million sperm/mL) showed no association between this deletion and male infertility. 61 There was also no association between gr/gr deletion and oligo-/azoospermia found in a 2005 study of 348 German men with non-obstructive oligo-/azoospermia. 62 Additionally, some studies have pointed to gr/gr duplication as a significant risk factor for male infertility in Asian men (OR = 2.71, 95% CI = 1.38‐5.32, P = 0.004), but not European men.…”

Section: Partial Azfc Deletions and Duplicationsmentioning

confidence: 92%

Y-Chromosome Microdeletions: A Review of Prevalence, Screening, and Clinical Considerations

Huffman¹,

Haney²,

Kohn³

2021

TACG

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Deletions within the male-specific region of the Y-chromosome, known as Y-Chromosome Microdeletions (YCMs), are present in as many as 5% and 10% of severe oligospermic and azoospermic men, respectively. These microdeletions are distinguished by which segment of the Y chromosome is absent, identified as AZFa (the most proximal segment), AZFb (middle), and AZFc (distal). The reported prevalence of YCMs within the world’s populations of infertile men displays vast heterogeneity, ranging from less than 2% to over 24% based on region and ethnicity. AZFc is the most commonly identified YCM, and its phenotypic presentation provides for the highest chance for fertility through artificial reproductive techniques. Conversely, deletions identified in the subregions of AZFa, AZFb, or any combination of regions containing these segments, are associated with low probabilities of achieving pregnancy. A putative mechanism explaining this discrepancy lies within the expression of autosomal, DAZ-like genes which could serve to “rescue” wild type AZFc gene expression and hence spermatogenesis. Nevertheless, recent reports challenge this dogma and stress the importance of further analysis when an AZFb deletion is detected. The screening thresholds to determine which oligospermic and azoospermic men are tested for potential YCMs has been recently contested. More recent literature supports lowering the threshold from 5 million sperm/mL of ejaculate to 1 million/mL as the frequency of YCMs in men with sperm concentrations between 1 and 5 million sperm/mL is very low (~0.8%). As such, subsequent guidelines should recommend a lower screening threshold. While YCMs are extremely common globally, the understanding of their clinical significance in the field remains scattered and without consensus. Furthermore, very little is currently known about partial deletions within the AZFc region, such as b1/b3, b2/b3, and gr/gr. Hence, this review aimed to summarize and discuss modern trends in the epidemiology, screening guidelines, and clinical considerations pertaining to YCMs.

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The association of gr/gr deletion in the Y chromosome and impaired spermatogenesis in Bulgarian males: a pilot study

Cited by 4 publications

References 24 publications

High incidence of AZF duplications in clan-structured Iranian populations detected through Y chromosome sequencing read depth analysis

High incidence of AZF duplications in clan-structured Iranian populations detected through Y chromosome sequencing read depth analysis

Lack of Association Between Partial Y chromosome AZFc-gr/gr Deletions and Male Infertility

Y-Chromosome Microdeletions: A Review of Prevalence, Screening, and Clinical Considerations

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