DAZ Gene Research Articles

Rapid detection of mouse spermatogenic defects by testicular cellular composition analysis via enhanced deep learning model.

Histological analysis of the testicular sections is paramount in infertility research but tedious and often requires months of training and practice. Establish an expeditious histopathological analysis of mutant mice testicular sections stained with commonly available hematoxylin and eosin (H&E) via enhanced deep learning model MATERIALS AND METHODS: Automated segmentation and cellular composition analysis on the testes of six mouse reproductive mutants of key reproductive gene family, DAZ and PUMILIO gene family via H&E-stained mouse testicular sections. We improved the deep learning model with human interaction to achieve better pixel accuracy and reduced annotation time for histologists; revealed distinctive cell composition features consistent with previously published phenotypes for four mutants and novel spermatogenic defects in two newly generated mutants; established a fast spermatogenic defect detection protocol for quantitative and qualitative assessment of testicular defects within 2.5-3h, requiring as few as 8 H&E-stained testis sections; uncovered novel defects in AcDKO and a meiotic arrest defect in HDBKO, supporting the synergistic interaction of Sertoli Pum1 and Pum2 as well as redundant meiotic function of Dazl and Boule. Our testicular compositional analysis not only could reveal spermatogenic defects from staged seminiferous tubules but also from unstaged seminiferous tubule sections. Our SCSD-Net model offers a rapid protocol for detecting reproductive defects from H&E-stained testicular sections in as few as 3h, providing both quantitative and qualitative assessments of spermatogenic defects. Our analysis uncovered evidence supporting the synergistic interaction of Sertoli PUM1 and PUM2 in maintaining average testis size, and redundant roles of DAZ family proteins DAZL and BOULE in meiosis.

Y-chromosome haplogroups and Azoospermia Factor (AZF) analysis in Tunisian infertile male

The aim of the present study was to clarify the implication of Y chromosome genetic variations and haplogroups in Tunisian infertile men. A total of 27 Y-chromosomal binary markers partial microdeletions (gr/gr, b1/b3 and b2/b3) and copy number variation of DAZ and CDY genes in the AZFc region were analysed in 131 Tunisian infertile men with spermatogenic failure and severe reduced sperm concentrations and in 85 normospermic men as controls. Eleven different haplogroups in the overall population study (E3b2; J1J*, E1, E3b*, F, G, K, P/Q, R*, R1* and R1a1) were found. Interestingly, the J1J* haplogroup was significantly more frequent in azoo/oligospermic patients than in normospermic men (35.1% and 22.3%, respectively (p value = 0.04)). Results showed also that patients without DAZ/CDY1 copies loss and without partial microdeletions belonged to the R1 haplogroup. The relative high frequencies of two haplogroups, E3b2 (35.1%) and J (30%) was confirmed in Tunisia. We reported in the present study and for the first time, that J1J* haplogroup may confer a risk factor for infertility in the Tunisian population and we suggested that R1 haplogroup may ensure certain stability to Y-chromosome in Tunisian men.

Association of DAZL polymorphisms and DAZ deletion with male infertility: a systematic review and meta-analysis.

Various populations have been investigated for the occurrence of two key DAZL polymorphisms, 260A > G (rs11710967) and 386A > G (rs121918346), as well as complete DAZ cluster deletion, with conflicting results. The purpose of the current meta-analysis was to investigate if there is an association between DAZL polymorphisms and complete deletion of the DAZ cluster gene with male infertility. Up until September 2022, a thorough search was conducted in the Pubmed and Google scholar databases. For 260A > G polymorphism, 8 studies with 2077 cases and 1398 controls, 13 studies for 386A > G polymorphism (4343 cases and 3727 controls) and 17 studies of DAZ deletion (2820 cases and 1589 controls) were included in the pooled analysis. All of the studies were statistically analysed by Review Manager 5.4, and publication bias was evaluated with JASP 0.16.2.0 software utilising funnel plots and Egger's linear regression test. The meta analysis result for pooled data indicated no association between 260A > G and 386A > G polymorphisms and male infertility in any of the genetic models or ethnicities. However, there was a definite correlation between complete deletion of the DAZ gene cluster and male infertility, with an OR = 13.23, 95% confidence interval (6.63-26.39), and p < 0.00001. In the stratified analysis by ethnicity, Caucasians and Asian ethnic groups showed the similar relationship. In order to arrive at more definitive conclusions, further study should be conducted, including studies from a larger range of nations and nationalities.

Y-chromosome genes associated with sertoli cell-only syndrome identified by array comparative genome hybridization

BackgroundThe precise contribution of each chromosome gene or gene family in achieving male fertility is still the subject of debate. Most studies have examined male populations with heterogeneous causes of infertility, and have therefore reached controversial or uncertain conclusions. This study uses Y-chromosome array-based comparative genomic hybridization (aCGH) to examine a population of males with a uniform sertoli cell-only syndrome (SCOS) infertility phenotype. MethodsInitial analysis of gene copy number variations in 8 SCOS patients, with determination of the log-ratio of probe signal intensity against a DNA reference, was performed using the Y-chromosome NimbleGen aCGH. To confirm the role of candidate genes, real-time quantitative RT-PCR was used to compare 19 patients who had SCOS non-obstructive azoospermia with 15 patients who had obstructive azoospermia but normal spermatogenesis. ResultsOur initial aCGH experiments identified CDY1a and CDY1b double deletions in all 8 patients who had total germ cell depletion. However, 5 patients had DAZ1/2 and DAZ3/4 deletions, 1 patient had a DAZ2 and DAZ3/4 deletion, and 2 patients had no DAZ1/2 or DAZ3/4 deletions. Examination of testicular mRNA expression in another 19 patients with SCOS indicated all patients had no detectable levels of CDY1. ConclusionsOur findings indicate that CDY1 deletion in SCOS patients, and analysis of the expression of DAZ and CDY1 genes using aCGH and quantitative RT-PCR, may be useful to predict the presence of mature spermatozoa.

External and Genetic Conditions Determining Male Infertility.

We explain environmental and genetic factors determining male genetic conditions and infertility and evaluate the significance of environmental stressors in shaping defensive responses, which is used in the diagnosis and treatment of male infertility. This is done through the impact of external and internal stressors and their instability on sperm parameters and their contribution to immunogenetic disorders and hazardous DNA mutations. As chemical compounds and physical factors play an important role in the induction of immunogenetic disorders and affect the activity of enzymatic and non-enzymatic responses, causing oxidative stress, and leading to apoptosis, they downgrade semen quality. These factors are closely connected with male reproductive potential since genetic polymorphisms and mutations in chromosomes 7, X, and Y critically impact on spermatogenesis. Microdeletions in the Azoospermic Factor AZF region directly cause defective sperm production. Among mutations in chromosome 7, impairments in the cystic fibrosis transmembrane conductance regulator CFTR gene are destructive for fertility in cystic fibrosis, when spermatic ducts undergo complete obstruction. This problem was not previously analyzed in such a form. Alongside karyotype abnormalities AZF microdeletions are the reason of spermatogenic failure. Amongst AZF genes, the deleted in azoospermia DAZ gene family is reported as most frequently deleted AZF. Screening of AZF microdeletions is useful in explaining idiopathic cases of male infertility as well as in genetic consulting prior to assisted reproduction. Based on the current state of research we answer the following questions: (1) How do environmental stressors lessen the quality of sperm and reduce male fertility; (2) which chemical elements induce oxidative stress and immunogenetic changes in the male reproductive system; (3) how do polymorphisms correlate with changes in reproductive potential and pro-antioxidative mechanisms as markers of pathophysiological disturbances of the male reproductive condition; (4) how do environmental stressors of immunogenetic disorders accompany male infertility and responses; and (5) what is the distribution and prevalence of environmental and genetic risk factors.

Is the primary AZFc duplication a potential risk for male infertility?: A systematic review and meta-analysis.

Numerous studies have been performed to investigate the association between the primary AZFc duplication and male infertility risk; however, the sample sizes have been small and the results have been controversial. A meta-analysis was performed to assess these associations. A systematic search was conducted to identify all relevant studies from the PubMed, Web of Science, Medline, CNKI, and Wanfang databases up to October 22, 2019. The odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the strength of associations. All of the statistical analyses were conducted by using RevMan 5.3. Eleven studies were identified that involved 3140 infertile men and 2280 fertile men. Overall, there was a statistically significant association between the primary AZFc duplication and male infertility (OR=1.66, 95% CI =1.29-2.14, P<.0001). In the subgroup analysis by ethnic group, a statistically significant association between the primary AZFc duplication and male infertility was observed in Asian men (OR = 2.26, 95% CI =1.64-3.12, P<.00001), but not in European men (OR = 0.90, 95% CI=0.59-1.38, P=.64). For subtypes of the primary AZFc duplication, a statistically significant association was observed between the gr/gr duplication-only (OR =2.71, 95% CI =1.38-5.32, P=.004) and infertility in Asian men. Asian men with the primary AZFc duplication resulting in more than four DAZ genes were found to be at an increased risk for infertility (OR =2.70, 95% CI =1.49-4.89, P=.001). Our meta-analysis provides an unprecedented illustration of how the association between the primary AZFc duplication and male infertility may be dependent on ethnicity or geographic location. Furthermore, gr/gr duplication or increased DAZ copy number can be detrimental to spermatogenesis in Asian men.

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

BackgroundThe microdeletions of the Y chromosome are associated with a decreased number of sperm cells in the ejaculate and male infertility. One such deletion is the gr/gr, which leads to reduction of the alleles in the DAZ gene. In order to evaluate its role, 30 patients with sperm count below 5 × 106/mL and 30 normal fertile men were genotyped for microdeletions in Azoospermia Factor (AZF) region, including gr/gr deletion.ResultsTwenty-one men (70.00%) from the males with impaired fertility had a normal genotype, seven men (23.33%) were carriers of a gr/gr deletion, and two men (6.67%) demonstrated a deletion of the AZFc region. From the control group, there were 22 men (73.33%) with no deletion, seven (23.33%) carried a gr/gr deletion, and one man (3.33%) carried a possible deletion in the b1-b4 region of the Y chromosome. The gr/gr deletion of the Y chromosome showed a statistically nonsignificant difference (p = 0.94, alpha < 0.05) with the control group (chi-square, degrees of freedom 0.006).ConclusionThe results from the research show no association between this deletion and male infertility in the studied population. Despite the small sample size, the high frequency of the gr/gr deletion, found in the control group, suggests that this variant may not be associated with impaired spermatogenesis.

Gr/gr deletion predisposes to testicular germ cell tumour independently from altered spermatogenesis: results from the largest European study.

The association between impaired spermatogenesis and TGCT has stimulated research on shared genetic factors. Y chromosome-linked partial AZFc deletions predispose to oligozoospermia and were also studied in TGCT patients with controversial results. In the largest study reporting the association between gr/gr deletion and TGCT, sperm parameters were unknown. Hence, it remains to be established whether this genetic defect truly represents a common genetic link between TGCT and impaired sperm production. Our aim was to explore the role of the following Y chromosome-linked factors in the predisposition to TGCT: (i) gr/gr deletion in subjects with known sperm parameters; (ii) other partial AZFc deletions and, for the first time, the role of partial AZFc duplications; (iii) DAZ gene dosage variation. 497 TGCT patients and 2030 controls from two Mediterranean populations with full semen/andrological characterization were analyzed through a series of molecular genetic techniques. Our most interesting finding concerns the gr/gr deletion and DAZ gene dosage variation (i.e., DAZ copy number is different from the reference sequence), both conferring TGCT susceptibility. In particular, the highest risk was observed when normozoospermic TGCT and normozoospermic controls were compared (OR = 3.7; 95% CI = 1.5-9.1; p = 0.006 for gr/gr deletion and OR = 1.8; 95% CI = 1.1-3.0; p = 0.013 for DAZ gene dosage alteration). We report in the largest European study population the predisposing effect of gr/gr deletion to TGCT as an independent risk factor from impaired spermatogenesis. Our finding implies regular tumour screening/follow-up in male family members of TGCT patients with gr/gr deletion and in infertile gr/gr deletion carriers.

Prenatal diagnosis of sex chromosome mosaicism with two marker chromosomes in three cell lines and a review of the literature.

The present study described the diagnosis of a fetus with sex chromosome mosaicism in three cell lines and two marker chromosomes. A 24‑year‑old woman underwent amniocentesis at 21weeks and 4days of gestation due to noninvasive prenatal testing identifying that the fetus had sex chromosome abnormalities. Amniotic cell culture revealed a karyotype of 45,X[13]/46,X,+mar1[6]/46,X,+mar2[9], and prenatal ultrasound was unremarkable. The woman underwent repeat amniocentesis at 23weeks and 4days of gestation for molecular detection. Single nucleotide polymorphism (SNP) microarray analysis on uncultured amniocytes revealed that the fetus had two Y chromosomes and 7.8‑Mb deletions in Yq11.222q12. The deletion regions included DAZ, RBMY and PRY genes, which could cause spermatogenesis obstacle and sterility. Interphase fluorescence insitu hybridization (FISH) using centromeric probes DXZ1/DYZ3/D18Z1 was performed on uncultured amniocytes to verify the two marker chromosomes to be Y chromosome derivatives. According to these examinations, the mar1 was identified as a derivative of the Y chromosome with a deletion in Yq11.222q12, and the mar2 was identified as a dicentric derivative of the Y chromosome. The molecular karyotype was therefore 45,X,ish(DXZ1+, DYZ3‑,D18Z1++)[5]/46,X,del(Y)(q11.222),ish(DXZ1+,DYZ3+,D18Z1++)[11]/46, X,idic(Y)(q11.222),ish(DXZ1+,DYZ3++,D18Z1++)[14]. The comprehensive use of cytogenetic, SNP array and FISH detections was advantageous for accurately identifying the karyotype, identifying the origin of the marker chromosome and preparing effective genetic counseling.

Age-related and photoperiodic variation of the DAZ gene family in the testis of the Syrian hamster (Mesocricetus auratus).

SummaryThe Deleted in AZoospermia (DAZ) gene family regulates the development, maturation and maintenance of germ cells and spermatogenesis in mammals. The DAZ family consists of two autosomal genes, Boule and Dazl (Daz-like), and the Daz gene on chromosome Y. The aim of this study was to analyze the localization of DAZL and BOULE during testicular ontogeny of the seasonal-breeding Syrian hamster, Mesocricetus auratus. We also evaluated the testicular expression of DAZ family genes under short- or long-photoperiod conditions. In the pre-pubertal and adult testis, DAZL protein was found mainly in spermatogonia. BOULE was found in the spermatogonia from 20 days of age and during the pre-pubertal and adult period it was also detected in spermatocytes and round spermatids. DAZL and BOULE expression in spermatogonia was strictly nuclear only in 20-day-old hamsters. We also detected the novel mRNA and protein expression of BOULE in Leydig cells. In adult hamsters, Dazl expression was increased in regressed testis compared with non-regressed testis and DAZL protein expression was restricted to primary spermatocytes in regressed testis. These results show that DAZL and BOULE are expressed in spermatogonia at early stages in the Syrian hamster, then both proteins translocate to the cytoplasm when meiosis starts. In the adult regressed testis, the absence of DAZL in spermatogonia might be related to the decrease in germ cell number, suggesting that DAZ gene family expression is involved in changes in seminiferous epithelium during photoregression.

Examination of Y-Chromosomal Microdeletions and Partial Microdeletions in Idiopathic Infertility in East Hungarian Patients.

Purpose:The aim of this study was to establish the Y chromosome microdeletion and partial AZFc microdeletion/duplication frequency firstly in East Hungarian population and to gain information about the molecular mechanism of the heterogeneous phenotype identified in males bearing partial AZFc deletions and duplications.Materials and Methods:Exactly determined sequences of azoospermia factor (AZF) region were amplified. Lack of amplification was detected for deletion. To determine the copy number of DAZ and CDY1 genes, we performed a quantitative analysis. The primers flank an insertion/deletion difference, which permitted the polymerase chain reaction products to be separated by polyacrylamide gel electrophoresis.Statistical Analysis Used:Mann–Whitney/Wilcoxon two-sample test, Kruskal–Wallis test, and two-sample t-probe were used for statistical analysis.Results:AZFbc deletion was detected only in the azoospermic cases; AZFc deletion occurred significantly more frequently among azoospermic patients, than among oligozoospermic males. The frequency of gr/gr deletions was significantly higher in the oligozoospermic patients than in the normospermic group. The b2/b3 deletion and partial duplications were not different among our groups, while b1/b3 deletion was found only in the azoospermic group. In infertile males and in normozoospermic controls, similar Y haplogroup distribution was detected with the highest frequency of haplogroup P. The gr/gr deletion with P haplogroup was more frequent in the oligozoospermic group than in the normozoospermic males. The b2/b3 deletion with E haplogroup was the most frequent, found only in the normozoospermic group.Conclusions:Y microdeletion screening has prognostic value and can affect the clinical therapy. In case of Y chromosome molecular genetic aberrations, genetic counseling makes sense also for other males in the family because these types of aberrations are transmittable (from father to son 100% transmission).

An Infertility SRY-Negative 46, XX Male Detected by Quantitative Fluorescent Polymerase Chain Reaction

Taking a frequency of 1 in 20,000–25,000 males, De la Chappelle syndrome (46, XX male) is a rare syndrome which exists in different clinical categories with ambiguous genitalia or partially to fully mature male genitalia, in combination with complete or incomplete masculinization. A case of SRY-negative XX male is reported with complete masculinization but with infertility. The patient was mature enough to have full genitalia with descended but small testes and no signs of undervirilization. There were 14 markers in the quantitative fluorescent polymerase chain reaction (QF-PCR): amelogenin gene, presented on X and Y chromosomes allows for the determination of the Y/X ratio (AMEL marker), TAF9B gene presented on chromosomes X and 3 permits the determination of X/chromosome 3 ratio (TAF9B marker or T3 marker), ten non- polymorphic Y-specific markers (SRY, sY84 and sY86 in AZFa region, sY127 and sY134 in AZFb region, sY254, sY255, sY1191, sY1192 and sY1291 in AZFc region), and co-amplification of DAZ/DAZL and CDY2/CDY1 fragments that permit determination of the DAZ, CDY1 and CDY2 gene copy number. The study resulted that there were only two peaks of markers: AMELX/Y marker produced a peak area ratio of 1:0 and T3 with the ratio of 2:2, indicating the presence of two X chromosomes in this case. The absence of the Y chromosome was confirmed when repeating peripheral blood culture for chromosome: there are 46 chromosomes with XX constitution. The first reported case in Mekong Delta, Vietnam is reported of a SRY-negative 46, XX male with normal male phenotype and infertility.

Effect of gr/gr microdeletion in partial AZFc deletion on human spermatogenesis

Objectives To inverstigate the effect of gr/gr subdeletion in partial AZFc deletion on human spermatogenesis. Methods We assessed The prevalence of gr/gr deletion in a population of both normospermic and infertile men with severe impairment of spermatogenesis were assessed, the contribution of these gr/gr deletion to male infertility was determined. A combined methodological approach that included the detection of the different DAZ gene copies by sequence nucleotide variant (SNV) analysis and AZFc-specific sequence tagged site (STS) markers was used. Results Type of gr/gr deletion was detected in 27 cases of 278 males with oligozoospermic and 17 cases of 220 donors. There was no difference in the prevalence of gr/gr deletion comparing oligozoospermic and normospermic groups (P=0.438). Of the 27 men with the gr/gr deletion, 23 cases exhibited the doublet deletion of DAZ1/DAZ2 and 1 case showed the DAZ3/DAZ4 deletion. In the normozoospermic population, 16 cases of gr/gr-DAZ3/DAZ4 deletions and one gr/gr-DAZ1/DAZ2 deletion were found. There was a significant difference when comparing gr/gr-DAZ1/DAZ2 deletions vs. gr/gr-DAZ3/DAZ4 deletions in the oligozoospermic and normospermic groups (P=0.000). Conclusions The gr/gr-DAZ3/DAZ4 deletion may not be sufficient to cause spermatogenic impairment. In addition, gr/gr microdeletions, which involve the DAZ1/DAZ2 region, may be a main cause of low sperm concentration and spermatogenic failure in the south chinese population. Key words: Spermatogenesis; Y Chromosome

Gr/gr-DAZ2-DAZ4-CDY1b deletion is a high-risk factor for male infertility in Tunisian population

The azoospermia factor c (AZFc) region harbors multi-copy genes that are expressed in the testis. Deletions of this region lead to reduced copy numbers of these genes. In this present study we aimed to determine the frequency of AZFc subdeletion in infertile and fertile men from Tunisia and to identify whether deletions of DAZ and CDY1 gene copies are deleterious on spermatogenesis and on semen quality. We studied a group of 241 infertile men and 115 fertile healthy males using a sequence tagged site (STS)±method. To gain insight into the molecular basis of the heterogeneous phenotype observed in men with the deletion we defined the type of DAZ and CDY1 genes deleted. We reported in the present study and for the first time a new type of AZFc deletion (gr/gr-DAZ2-DAZ4-CDY1b) and hypothesis that this new deletion is the result of two successive events. We also demonstrated that this deletion constitutes a relative high-risk factor for male infertility in Tunisian population.

Analysis of partial azoospermia factor c deletion and DAZ copy number in azoospermia and severe oligozoospermia.

Microdeletions of the azoospermia factor (AZF) regions in the Y chromosome are a well-known genetic cause of male infertility, resulting in impairment of spermatogenesis. However, the partial deletions of AZFc region related to spermatogenetic impairment are controversial. We investigated partial deletion of AZFc region and DAZ copy number in a population of Iranian infertile men and normozoospermic controls. In total, 154 infertile men (113 patients with azoospermia, 41 with oligozoospermia) and 111 normozoospermic controls were analysed using PCR. Gene dosage analysis of the DAZ genes was performed by fragment analysis. Our results showed that the frequencies of gr/gr deletion in the azoospermic, severe oligozoospermic and normozoospermic men were 4.4% (5/113), 7.3% (3/41) and 1.8% (2/111) respectively. In the azoospermic patients, the frequency of b2/b3 was 1.8% (2/113). Partial AZFc deletions were not significantly different between the infertile and normozoospermic men. The frequencies of gr/gr deletions and b2/b3 were not significantly different between the azoospermic/severe oligozoospermic men and normozoospermic controls. Our data suggested that gr/gr deletion was not associated with azoospermia/oligozoospermia in an Iranian population.

Mutational landscape of the human Y chromosome-linked genes and loci in patients with hypogonadism.

Sex chromosome-related anomalies engender plethora of conditions leading to male infertility. Hypogonadotropic hypogonadism (HH) is a rare but well-known cause of male infertility. Present study was conducted to ascertain possible consensus on the alterations of the Y-linked genes and loci in males representing hypogonadism (H), which in turn culminate in reproductive dysfunction. A total of nineteen 46, XY males, clinically diagnosed with H (11 representative HH adults and eight prepubertal boys suspected of having HH) were included in the study. Sequence-tagged site screening,SRY gene sequencing,fluorescence in situ hybridization mapping (FISH), copy number and relative expression studies by real-time PCR were conducted to uncover the altered status of the Y chromosome in the patients. The result showed random microdeletions within the AZFa (73%)/b (78%) and c(26%) regions. Sequencing of the SRY gene showed nucleotide variations within and outside of the HMG box in four males (21%). FISH uncovered mosaicism for SRY, AMELY,DAZ genes and DYZ1 arrays, structural rearrangement for AMELY (31%) and duplication of DAZ (57%) genes. Copy number variation for seven Y-linked genes (2-8 rounds of duplication), DYZ1 arrays (495-6201 copies) and differential expression of SRY,UTY and VCY in the patients' blood were observed. Present work demonstrates the organizational vulnerability of several Y-linked genes in H males. These results are envisaged to be useful during routine diagnosis of H patients.

Screening for AZFc partial deletions in Dravidian men with nonobstructive azoospermia and oligozoospermia.

Dravidians are the predominant population residing in South India with a diverse genetic structure. Considering various genetic discoveries taking place today, it is evident that deletions in the AZFc region are the most common cause of severe spermatogenic failure (SSF) in various populations studied. However, it is significant to note that there is a paucity of scientific literature on AZFc subdeletion screening among the Dravidian population. To investigate the prevalence and association of AZFc subdeletion patterns among Dravidian men with nonobstructive azoospermia (NOA) and oligozoospermia. A population of 354 subjects, including 120 patients with NOA, 109 with oligozoospermia, and 125 normal male controls, were screened using locus-specific sequence tag site markers. We found 21 (9.17%) patients with classical AZF deletion, while no deletions were observed in controls. After excluding the samples with AZF deletions, the remaining 208 infertile and 125 control samples were screened for partial AZFc deletions using a standardized multiplex polymerase chain reaction and on analysis revealed that 13 (6.25%) of the infertile samples possessed gr/gr subdeletions and 15 (7.21%) of the infertile samples possessed b2/b3 subdeletions. Six (4.8%) of the normal samples were found to carry gr/gr subdeletions and two (1.6%) had b2/b3 deletions. The b1/b3 deletion was not observed in any of the patient and control samples screened. Our finding shows that there is a strong association between b2/b3 subdeletion and SSF in the Dravidian population (odds ratio, 4.78; 95% confidence interval 1.07-21.26) (p=0.018). Further studies, including gene copy typing for DAZ and CDY genes and a comprehensive haplogrouping analysis, are recommended in a large and well-selected patient group to elude the genetic mechanism behind this association.

DAZ Family Proteins, Key Players for Germ Cell Development.

DAZ family proteins are found almost exclusively in germ cells in distant animal species. Deletion or mutations of their encoding genes usually severely impair either oogenesis or spermatogenesis or both. The family includes Boule (or Boll), Dazl (or Dazla) and DAZ genes. Boule and Dazl are situated on autosomes while DAZ, exclusive of higher primates, is located on the Y chromosome. Deletion of DAZ gene is the most common causes of infertility in humans. These genes, encoding for RNA binding proteins, contain a highly conserved RNA recognition motif and at least one DAZ repeat encoding for a 24 amino acids sequence able to bind other mRNA binding proteins. Basically, Daz family proteins function as adaptors for target mRNA transport and activators of their translation. In some invertebrate species, BOULE protein play a pivotal role in germline specification and a conserved regulatory role in meiosis. Depending on the species, DAZL is expressed in primordial germ cells (PGCs) and/or pre-meiotic and meiotic germ cells of both sexes. Daz is found in fetal gonocytes, spermatogonia and spermatocytes of adult testes. Here we discuss DAZ family genes in a phylogenic perspective, focusing on the common and distinct features of these genes, and their pivotal roles during gametogenesis evolved during evolution.

New Sequence Variations in Spermatogenesis Candidates Genes.

The aim of this paper was to estimate the frequency and types of mutations in key candidate genes involved in spermatogenesis, and their potential role as a cause of azoospermia /cryptozoospermia. The sequencing of the coding region of genes DBY, RBMY, DAZ, CDY and BPY2, excluding the promoter region, was performed in a series of 25 patients with azoospermia or severe oligozoospermia without AZF microdeletions. The exon 3 from the DAZL gene (DAL3) was also sequenced. The sequences obtained were analyzed by ProSeq, DnaSP v5 and compared with the database using Blastn and tblastx. 16 of the 25 patients showed some type of variants, such as transversions, transitions, deletions and/or insertions in the DAZ, DAZL, CDY and RBMY genes. The mutated sequences had between 97 and 99% homology with the specific protein of every gene, except the DAZL (73%) and DAZ (94%) proteins. The variants found have not been described previously, suggesting they could be mutations that might affect protein function.

Identification of null and duplicated alleles for forensic DYS549, DYS527 and DYS459 in male infertility population

DYS549, DYS527, and DYS459 loci, located on the azoospermia factor (AZF) region and widely used in forensic and pedigree analysis, may be specifically altered in infertile patients, which will obscure the result of individual identification using Y-STR (Y chromosome short tandem repeat). In this study, we determined the AZF polymorphism by STS(-/-) (sequence tagged site) and DAZ, CDY1 gene copy numbers, and screened the samples by 14 Y-STR loci to disclose the unusual genotype of Y-STR in male infertility population. The 240 infertile males including non-obstructive azoospermia, severe oligozoospermia and congenital bilateral absence of vas deferens (CBVAD) were analyzed with a modified multiplex PCR system for AZF microdeletion STSs. AZF microdeletions were found in 40 cases (16.67%) (AZFa deletion, two cases; AZFb deletion, two cases; AZFc deletion, 30 cases; AZFb+c deletion, six cases). Further screening by the 14 Y-STR loci in samples with microdeletions, we found DYS549 allelic loss in all the cases with AZFb deletion, DYS527 and DYS459 allelic loss in all the cases with AZFc deletion, DYS549, DYS527, and DYS459 allelic loss in all the cases with AZFb+c deletion. Ten patients (4.17%) with AZFc partial duplication (one CBVAD case, two non-obstructive azoospermia cases, seven severe oligozoospermia cases) were found by DAZ and CDY1 gene dosage analysis. In conclusion, the unusual patterns of DYS549, DYS527, and DYS459 are caused by genetic defects rather than experimental bias. Revealing the locus heterogeneity in male infertility population can enrich the Y-STR database and assist in interpreting abnormal STR genotype in forensic DNA testing.