AZFb Regions Research Articles

Identification of Y chromosome microdeletions in infertile Turkish men.

The aim of this study was to determine the frequencies of Y chromosome microdeletions in infertile azoospermic and oligozoospermic Turkish men and in healthy control subjects. Sixty-four azoospermic and 51 oligozoospermic patients infertile patients, and 70 healthy men who had a child without the aid of assisted reproductive technologies were included in this study. DNA was extracted from peripheral blood samples collected from the patients. Following multiplex PCR performed with 15 different primer sequences, Y chromosome AZFa, AZFb, AZFc and AZFd region microdeletions were determined by agarose gel electrophoresis. Y chromosome microdeletions were detected in 8 (12.5%) patients in the azoospermia group and 3 (5.9%) patients in the oligozoospermia group. The overall frequency of Y chromosome microdeletions in all infertile cases was 9.6%. Y chromosome microdeletions were not found in the healthy control group. Among the infertile cases, there were 4 (3.48%) AZFa, 2 (1.74%) AZFb, 3 (2.61%) AZFc and 7 (6.09%) AZFd region microdeletions. Y chromosome microdeletions were not found among healthy men in the control group. The presence of Y chromosome microdeletions among azoospermic and oligozoospermic infertile males suggests that routine genetic testing and genetic counseling prior to the use of assisted reproduction techniques are necessary.

Clinical characteristics, cytogenetic and molecular findings in patients with disorders of sex development

The clinical characteristics of patients with disorders of sex development (DSD), and the diagnostic values of classic cytogenetic and molecular genetic assays for DSD were investigated. In the enrolled 56 cases, there were 9 cases of 46,XY DSD, 6 cases of Turner syndrome (TS), one case of Super female syndrome, 25 cases of Klinefelter syndrome, 14 cases of 46,XX DSD, and one case of autosomal balanced rearrangements with hypospadias. The diagnosis of sex was made through physical examination, cytogenetic assay, ultrasonography, gonadal biopsy and hormonal analysis. PCR was used to detect SRY, ZFX, ZFY, DYZ3 and DYZ1 loci on Y and X chromosomes respectively. The DSD patients with the same category had similar clinical characteristics. The karyotypes in peripheral blood lymphocytes of all patients were identified. PCR-based analysis showed presence or absence of the X/Y-linked loci in several cases. Of the 9 cases of 46,XY DSD, 6 were positive for SRY, 9 for ZFX/ZFY, 9 for DYZ3 and 8 for DYZ1 loci. Of the 6 cases of TS, only 1 case with the karyotype of 45,X,/46,XX/46,XY was positive for all 5 loci. Of the 25 cases of Klinefelter syndrome, all were positive for all 5 loci. In one case of rare Klinefelter syndrome variants azoospermia factor (AZF) gene detection revealed the loss of the AZFa+AZFb region. In 14 cases of 46,XX DSD, 7 cases were positive for SRY, 14 for ZFX, 7 for ZFY, 7 for ZYZ3, and 5 for DYZ1. PCR can complement and also confirm cytogenetic studies in the diagnosis of sex in cases of DSD.

Unusual Maternal Uniparental Isodisomic X Chromosome Mosaicism with Asymmetric Y Chromosomal Rearrangement

Infertile men with azoospermia commonly have associated microdeletions in the azoospermia factor (AZF) region of the Y chromosome, sex chromosome mosaicism, or sex chromosome rearrangements. In this study, we describe an unusual 46,XX and 45,X mosaicism with a rare Y chromosome rearrangement in a phenotypically normal male patient. The patient's karyotype was 46,XX[50]/45,X[25]/46,X,der(Y)(pter→q11.222::p11.2→pter)[25]. The derivative Y chromosome had a deletion at Yq11.222 and was duplicated at Yp11.2. Two copies of the SRY gene were confirmed by fluorescence in situ hybridization analysis, and complete deletion of the AZFb and AZFc regions was shown by multiplex-PCR for microdeletion analysis. Both X chromosomes of the predominant mosaic cell line (46,XX) were isodisomic and derived from the maternal gamete, as determined by examination of short tandem repeat markers. We postulate that the derivative Y chromosome might have been generated during paternal meiosis or early embryogenesis. Also, we suggest that the very rare mosaicism of isodisomic X chromosomes might be formed during maternal meiosis II or during postzygotic division derived from the 46,X,der(Y)/ 45,X lineage because of the instability of the derivative Y chromosome. To our knowledge, this is the first confirmatory study to verify the origin of a sex chromosome mosaicism with a Y chromosome rearrangement.

Cytogenetic and Yq microdeletion screening studies in infertile males

Infertility is defined as the inability of a sexually active couple to achieve pregnancy despite unprotected intercourse for a period of greater than 12 months. Infertility affects 15% of the infertile couples and in about half of them, male factor is responsible. It is due to low number, abnormal or immobile sperm production, or blockages that prevent the delivery of sperm. Illnesses, injuries, chronic health problems, lifestyle choices and other factors can also play a role. A total of 130 infertile males (43 azoospermic, 31 asthenospermic, 7 cryptozoospermic, 20 oligoasthenozoospermic, 29 normozoospermic) were analyzed for the presence of chromosomal abnormalities and Y chromosome classical microdeletions in the azoospermia factor (AZF) regions. Multiplex PCR amplification of genomic DNA was performed using two STS markers for each of the three non-overlapping regions, AZFa (sY84, sY86), AZFb (sY127, sY134) and AZFc (sY254, sY255) following standard guidelines. The markers ZFX/ZFY and sY14 (SRY) were included as internal controls. Two individuals showed Klinefelter syndrome (47,XXY) and three cases exhibited reciprocal translocations involving autosomes - t(3;17)(q26.2;p12), t(1;11)(p22.3;p13) and t(1;10)(q25;q24). Polymorphisms involving the heterochromatic regions of Y and the acrocentric chromosomes were seen in seven patients. The rest of the individuals exhibited a normal chromosomal pattern. The occurrence of chromosomal abnormalities was confined to only the azoospermia category which could reflect the small sample size. A deletion involving all the three AZF regions was detected in one individual while another showed a deletion in AZFb (partial) and AZFc regions. These results indicate a distinctly lower frequency of Y chromosomal microdeletions in the selected group of men with idiopathic infertility. The study needs to be extended using more primer sets defining these loci which play a major role in spermatogenesis.

A rare complex chromosomal rearrangement in an oligospermic male: a case report and review of the Chinese literature

A rare complex chromosomal rearrangement in an oligospermic male: a case report and review of the Chinese literature

Screening of Y chromosome microdeletions in 46,XY partial gonadal dysgenesis and in patients with a 45,X/46,XY karyotype or its variants

BackgroundPartial and mixed gonadal dysgenesis (PGD and MGD) are characterized by genital ambiguity and the finding of either a streak gonad and a dysgenetic testis or two dysgenetic testes. The karyotype in PGD is 46,XY, whereas a 45,X/46,XY mosaicism or its variants (more than two lineages and/or structural abnormalities of the Y chromosome) is generally found in MGD. Such mosaics are also compatible with female phenotype and Turner syndrome, ovotesticular disorder of sex development, and infertility in men with normal external genitalia. During the last few years, evidences of a linkage between Y microdeletions and 45,X mosaicism have been reported. There are also indications that the instability caused by such deletions might be more significant in germ cells. The aim of this work was to investigate the presence of Y chromosome microdeletions in individuals with PGD and in those with 45,X/46,XY mosaicism or its variants and variable phenotypes.MethodsOur sample comprised 13 individuals with PGD and 15 with mosaicism, most of them with a MGD phenotype (n = 11). Thirty-six sequence tagged sites (STS) spanning the male specific region (MSY) on the Y chromosome (Yp, centromere and Yq) were analyzed by multiplex PCR and some individual reactions.ResultsAll STS showed positive amplifications in the PGD group. Conversely, in the group with mosaicism, six individuals with MGD had been identified with Yq microdeletions, two of them without structural abnormalities of the Y chromosome by routine cytogenetic analysis. The deleted STSs were located within AZFb and AZFc (Azoospermia Factor) regions, which harbor several genes responsible for spermatogenesis.ConclusionsAbsence of deletions in individuals with PGD does not confirm the hypothesis that instability of the Y chromosome in the gonads could be one of the causes of such condition. However, deletions identified in the second group indicate that mosaicism may be associated with Y chromosome abnormalities detectable only at the molecular level. If patients with mosaicism and Y microdeletions reared as males decide to undergo in vitro fertilization, Y chromosomes which tend to be unstable during cell division may be transmitted to offspring.

Analysis of null alleles for 17 Y chromosome-short tandem repeat loci in infertile males

To investigate the characteristics of null allele for 17 Y-chromosomal short tandem repeats (Y-STR) loci in a group of infertile males. Two hundred thirty six infertile males featuring non-obstructive azoospermia and severe oligozoospermia were analyzed with an AmpFISTR ((R)) Yfiler (TM) kit. Deletions of azoospermia factor (AZF) fragments were confirmed with Y chromosome sequence-tagged sites (STSs) analysis using modified multiplex PCR. The overall prevalence of AZF microdeletions was 16.95% (40/236). In the non-obstructive azoospermia group, 13 cases had AZFc deletion, 6 cases had AZFb+c deletion, 2 cases had AZFa deletion, 1 case had AZFb deletion. In the severe oligozoospermia group, 17 cases had AZFc deletion and 1 had AZFb deletion. No AZFa+b+c deletion was detected. Forty cases showed null alleles by scanning of the 17 STR loci. Deletions of DYS438, DYS439, DYS437, DYS389I and DYS389II were found in the 2 cases with AZFa deletion. In patients with AZFb deletion, DYS392 and DYS385a/b were found deleted. Deletions of DYS448 were detected in all of the 30 cases with AZFc deletion. Deletions of DYS392, DYS385a/b, and DYS448 were found in 6 cases with AZFb+c deletion. Deletions of the Y chromosome AZF regions are associated with azoospermia and severe oligozoospermia. Null allele due to complete absence of AZFa, AZFb and AZFc regions may lead to misinterpretation in the sexual assault cases. Revealing the locus heterogeneity in male infertility population can enrich the Y-STR database and facilitate interpretation STR data in forensic DNA testing.

Non-chimerism and chimerism pseudo dicentric Y chromosome: two case reports about azoospermia and cytogenetic/molecular genetic analysis in the Chinese population

To report the cytogenetic and molecular genetic analysis of the first two cases of non-chimerism and chimerism karyotype in Chinese male patients who suffer from azoospermia, which may be caused by pseudo dicentric Y chromosomes. Case study. Academic reproductive medicine center. Two male patients with azoospermia, carrying pseudo dicentric Y chromosome. Review the records of inquiry, testicular biopsy, pathological examination, semen routine examination, endocrine evaluation, cytogenetic chromosomal analysis, and FISH detection of peripheral blood to evaluate Y chromosome deletion. To investigate the possible association among pseudo dicentric Y, chimeric status and azoospermia. Two patients were both diagnosed with azoospermia by a variety of andrology inspections. Further chromosomal analysis and FISH indicated their pseudo dicentric Y chromosome and different chimerism status. PCR confirmed simultaneous deletions of AZFb and AZFc regions in the Y chromosome of both patients. Pseudodicentric Y chromosome affecting the long arm may lead to a male phenotype by duplicating the sex-determining region of Y chromosome (SRY) fragment and chimeric status may further impact patient's hormone levels, which obstruct spermatogenesis. However, the deletion of the azoospermia factor (AZF) is likely the key factor that causes azoospermia.

Y chromosome azoospermia factor region microdeletions are not associated with idiopathic recurrent spontaneous abortion in a Slovenian population: association study and literature review

To investigate the potential association of Y chromosome microdeletions with idiopathic recurrent spontaneous abortion (IRSA) in a Slovenian population and compare our results with those of previously published studies in different populations, with the intention of clarifying the potential impact of Y chromosome microdeletions on IRSA. Case-control and association study. Departments of gynecology and obstetrics and university-based research laboratory. Male partners of 148 couples with at least three spontaneous pregnancy losses of unknown etiology, and 148 fertile men. Multiplex polymerase chain reactions. Azoospermia factor (AZF) regions were tested for Y chromosome microdeletions according to European Academy of Andrology/European Molecular Genetics Quality Network guidelines. The PubMed database was searched to retrieve articles linking Y chromosome microdeletions and susceptibility to IRSA. None of the IRSA or control men had microdeletions in the AZFa, AZFb, or AZFc regions. A total of nine previous studies examined the relationship between Y chromosome microdeletions and IRSA, yielding contradictory results, which we discuss in detail. On the basis of our comparisons, it is unlikely that Y chromosome microdeletions contribute to IRSA and are therefore currently not recommended for the routine evaluation of IRSA couples.

Hormone and genetic study in male to female transsexual patients.

Data of the literature demonstrated controversial results of a correlation between transsexualism and genetic mutations. To evaluate the hormone and gene profile of male-female (M-F) transsexual. Thirty M-F transsexuals aged 24-39. Seventeen had already undergone sex reassignment surgery, 13 were awaiting. All subjects had been undergoing estrogen and antiandrogen therapy. We studied hormones of the hypothalamus- pituitary-testicular axis, thyroid and adrenal profile, GH basal and after GHRH stimulation, IGF-I. The gene study analyzed SRY, AR, DAX1, SOX9, AZF region of the Y chromosome. Pre-surgery subjects had elevated PRL, reduced testosterone and gonadotropins. Post-surgery subjects showed reduced androgens, a marked increase in LH and FSH and normal PRL. Cortisol and ACTH were similar to reference values in pre- and post-surgery patients. There was a marked increase in the baseline and post-stimulation GH values in 6 of the 13 pre-surgery patients, peaking at T15. IGF-I was similar to reference values in both groups except for one post-surgery patient, whose level was below the normal range. There were no polymorphisms in the amplified gene region for SOX9, and a single nucleotide synonimous polymorphism for DAX1. No statistically significant differences were seen in the mean of CAG repeats between controls and transsexual subjects. SRY gene was present in all subjects. Qualitative analysis of the AZFa, AZFb, and AZFc regions did not reveal any microdeletions in any subject. This gender disorder does not seem to be associated with any molecular mutations of some of the main genes involved in sexual differentiation.

Success rate of microsurgical multiple testicular sperm extraction and sperm presence in the ejaculate in korean men with y chromosome microdeletions.

PurposeWe assessed the frequency of azoospermia factor a (AZFa), AZFb, and AZFc deletions and examined correlations between the deletion sites and the success rates of sperm presence within the ejaculate and surgical sperm retrieval in Korean men.Materials and MethodsA total of 1,919 azoospermic and severely oligozoospermic men were assessed for Y chromosome microdeletions. Among them, 168 men with AZF deletions were identified and their medical records were reviewed.ResultsOf the total 168 men with AZF deletions, there were 13 with AZFa, 10 with AZFb, 95 with AZFc, 37 with AZFbc, and 13 with AZFabc deletions. Of the 95 men with isolated AZFc deletion, 51 had the presence of sperm in the ejaculate. Of the infertile men with any other deletion, however, only two patients (one man with AZFb deletion and another with AZFbc deletion) showed the presence of sperm in the ejaculate. The success rates for surgical sperm retrieval were 7.1% (1/14) in men with AZFbc deletion and 54.8% (17/31) in the isolated AZFc deletion group. No sperm was obtained from the patients with AZFa or AZFb deletions who underwent microsurgical sperm retrieval. In the isolated AZFc deletion group, there were significant differences between azoospermic and severely oligozoospermic patients in terms of testicular volume and serum levels of follicle-stimulating hormone and luteinizing hormone, whereas no significant differences were found when the group was divided by surgical sperm retrieval outcomes.ConclusionsDeletions of the AZFa and AZFb regions are associated with severe spermatogenetic impairment. However, more than half of men with an AZFc deletion had sperm within the ejaculate or testis for in vitro fertilization with intracytoplasmic sperm injection.

Deletion or underexpression of the Y-chromosome genes CDY2 and HSFY is associated with maturation arrest in American men with nonobstructive azoospermia

Maturation arrest (MA) refers to failure of germ cell development leading to clinical nonobstructive azoospermia. Although the azoospermic factor (AZF) region of the human Y chromosome is clearly implicated in some cases, thus far very little is known about which individual Y-chromosome genes are important for complete male germ cell development. We sought to identify single genes on the Y chromosome that may be implicated in the pathogenesis of nonobstructive azoospermia associated with MA in the American population. Genotype-phenotype analysis of 132 men with Y-chromosome microdeletions was performed. Protein-coding genes associated with MA were identified by visual analysis of a genotype-phenotype map. Genes associated with MA were selected as those genes within a segment of the Y chromosome that, when completely or partially deleted, were always associated with MA and absence of retrievable testicular sperm. Expression of each identified gene transcript was then measured with quantitative RT-PCR in testicular tissue from separate cohorts of patients with idiopathic MA and obstructive azoospermia. Ten candidate genes for association with MA were identified within an 8.4-Mb segment of the Y chromosome overlapping the AZFb region. CDY2 and HSFY were the only identified genes for which differences in expression were observed between the MA and obstructive azoospermia cohorts. Men with obstructive azoospermia had 12-fold higher relative expression of CDY2 transcript (1.33 ± 0.40 vs. 0.11 ± 0.04; P=0.0003) and 16-fold higher expression of HSFY transcript (0.78 ± 0.32 vs. 0.05 ± 0.02; P=0.0005) compared to men with MA. CDY2 and HSFY were also underexpressed in patients with Sertoli cell only syndrome. These data indicate that CDY2 and HSFY are located within a segment of the Y chromosome that is important for sperm maturation, and are underexpressed in testicular tissue derived from men with MA. These observations suggest that impairments in CDY2 or HSFY expression could be implicated in the pathogenesis of MA.

Discrepancy in the Frequency of Y Chromosome Microdeletions Among Iranian Infertile Men with Azoospermia and Severe Oligozoospermia

There are discrepancies in the reported frequency of Y chromosome microdeletions among Iranian infertile men. The objective of this study was to determine the frequency of Y chromosome microdeletions in an Iranian population with azoospermia and severe oligozoospermia. Totally, 94 azoospermic and 21 severe oligozoospermic patients were screened for the presence of Y chromosome microdeletions. One hundred and five fertile men were included as a control group, as well. The screening of Yq microdeletions was performed by two multiplex PCRs using six STS markers. No microdeletions were detected in the men with severe oligozoospermia. In the azoospermic group 2/94 (2.13%) patients showed Y chromosome microdeletions. Among them, one patient had complete deletion of the AZFc region and the other showed complete deletion of both the AZFb and AZFc regions (AZFbc). No microdeletion was identified in the AZFa region. The estimated frequency of Y chromosome microdeletions in the present survey was lower than that of previous reports in Iranian populations.

A Novel Y Chromosome Microdeletion With the Loss of an Endogenous Retrovirus Related, Testis Specific Transcript in AZFb Region

We identified the endogenous retroviruses associated with TTYs (testis specific transcripts linked to the Y) in the AZFb region. We evaluated the relationship between endogenous retroviruses, and TTY expression patterns and function in spermatogenesis. We identified family members of TTYs in the AZFb region using computational screening. After investigating the relationship between the endogenous retrovirus genome and TTY expression patterns we screened genomic polymerase chain reaction products from TTY13 amplified from 790 Japanese men, including 275 with azoospermia, 285 with oligozoospermia and 230 who were fertile. Computational screening revealed that 3 members of the TTY family, TTY9, 10 and 13, were regulated by endogenous retroviruses in the AZFb region. Homologous recombination between long terminal repeat of the TTY13 associated human endogenous retrovirus-K14C resulted in TTY13 deletion events. These deletions were more common in patients with azoospermia and oligozoospermia than in fertile males. Specifically 15.63% of the azoospermia group, 10.88% of the oligozoospermia group and 0% of fertile controls had only the deletion variant, indicating an association between the homologous recombination rate and the severity of spermatogenesis failure that was statistically significant (p <0.05). Because of the finding of what are to our knowledge novel microdeletions due to endogenous retrovirus in the AZFb region, our study raises the possibility that specific variations in genomic structure may contribute to some forms of human idiopathic male infertility.

Loss of the AZFc region due to a human Y-chromosome microdeletion in infertile male patients

Infertility is a major reproductive health threat; the frequency of male infertility due to Y-chromosome microdeletions is 13-18% in the human population; these microdeletions involve recurrent loss of three non-overlapping regions designated as AZFa, AZFb and AZFc, associated with spermatogenic failure. Several contradictory reports have been published regarding deletion frequency based on sequence-tagged site markers and genotype-phenotype correlation. We examined the prevalence of Yq- deletion in 64 clinically diagnosed infertile male patients. We found a 3% frequency of microdeletion of the AZFc region; hormone profiles (FSH, LH and testosterone) showed significantly (P < 0.001) elevated levels compared to controls. No mutations were observed in the AZFa and AZFb regions, perhaps due to the selective use of sequence-tagged site markers.

Cytogenetic abnormalities and azoospermia factor (AZF)microdeletions in infertile men from Kuwait

Cytogenetic abnormalities and azoospermia factor (AZF)microdeletions in infertile men from Kuwait

Identification of new breakpoints in AZFb and AZFc

Microdeletions in AZFa, AZFb and AZFc regions lead to different patterns of male infertility, from severe oligozoospermia to non-obstructive azoospermia. Intrachromosomal homologous recombination mechanisms were already identified in patients with simultaneous microdeletions in the AZFb and AZFc regions. Ten patients with atypical AZFb and AZFc deletion patterns were studied. The definition of those microdeletions and the fine characterization of the respective breakpoints were performed using sequence tagged sites/single nucleotide variants-PCR and DNA sequencing. Y-chromosome haplogroups were determined to establish a putative association with the patterns obtained. Seven deletion patterns were identified, P5/terminal (30%; 3/10), P5/P1 distal (20%; 2/10), IR4/distal-P2, IR2/proximal-P1, IR4/distal-P1, P4/terminal and complete AZFb/c deletion (10%; 1/10). Breakpoint sequence analysis suggests that only in one patient the P5/P1 distal deletion pattern was due to a homologous recombination mechanism. Sequence alignment of the other deletion patterns suggest that they have resulted from non-homologous recombination mechanisms.

Do microdeletions in the AZF region of the Y chromosome accompany cryptorchidism in Turkish children?

To investigate the presence of Y chromosome microdeletions in children with cryptorchidism. Male patients aged between 1 and 17 years, who had been diagnosed by physical examination to have cryptorchid testes, were included in the study. Microdeletions of 24 gene loci belonging to the AZF-a, AZF-b and AZF-c regions of the Y chromosome were examined by multiplex polymerase chain reaction (PCR) multiplication of the DNA sample extracted from peripheral leukocytes. Sixty-four patients with a mean age of 7.82+/-3.21 (range: 1-17) years were included in the study. There was unilateral cryptorchidism in 53.1% (34/64) of the patients and bilateral cryptorchidism in 46.8% (30/48) of the patients. No microdeletion of gene loci on the AZF-a, AZF-b and AZF-c regions of the Y chromosome was determined in any patient. Studies on Y chromosome microdeletions are important due to a potential for the transmission of genetic abnormalities to offspring. Assisted reproduction techniques may cause the transmission of genetic abnormalities to offspring because the physiological fertilisation mechanism is bypassed. It was found that there was probably no aetiologic correlation between microdeletions in gene loci on the AZF-a, AZF-b and AZF-c regions of the Y chromosome and cryptorchidism.

Y chromosome microdeletions in Tunisian infertile males

To determine frequency of Y microdeletions in azoospermic and oligospermic Tunisian infertile males. A Sample of 146 Tunisian infertile males with a low sperm count (<5 x 10(6) sperms per mililiter) and normal karyotype was screened for Y chromosome microdeletions. 76 men were azoospermic and 70 men were oligospermic. Genomic DNA was isolated from blood and multiplex PCR was carried out with a set of 20 AZFa, AZFb and AZFc STS markers to detect the microdeletions as recommended by the European Academy of Andrology. In 10/146 (6.85%) subjects AZF deletions were observed. Of these ten males with microdeletions, 9/10 subjects were azoospermic (90%), 1/10 was oligospermic (10%). Frequency of microdeletions in azoospermic men was 9/76 (11.84%). None of the patients showed isolated microdeletion in the AZFa region, but one azoospermic man had deletion in the AZFb region. Eight azoospermic patients and one oligospremic man have AZFc microdeletions. AZFc and AZFb were deleted in three azoospermic patients. AZFc, AZFb and AZFa were deleted in three azoospermic patients We estimate the sensitivity of the test comprising six STS in our sample to be 90%. The incidence of Yq microdeletions in the study population of infertile Tunisian men falls within the range published in other countries. We suggest to analyze 9STS in the first step to detect efficiently Y microdeletions in our population.

SRY and AZF gene variation in male infertility: a cytogenetic and molecular approach

The aim of this study was to identify the genetic effects of Y chromosome and azoospermia factor (AZF) gene variation in men with infertility and to elucidate the molecular mechanism responsible for the identified point mutation. Chromosome analysis was performed according to standard methods on lymphocyte cultured cells and genomic DNA was extracted from the peripheral blood. Three sets of primers were used encompassing the AZFb, AZFc and SRY14 gene regions. Products were genotyped with single-strand comformational polymorphisim (SSCP) analysis. The profiles of the mutated genes were detected in five of three azoospermic and two oligoasthenozoospermic infertile males. The SSCP variability of the AZFc gene was detected in all of the cases, while sex-determining region Y (SRY) gene variation was detected in two of the current cases. Three cases with oligoasthenozoospermia showed mutated SSCP profiles in both their SRY and AZFc gene regions. No AZFb variation was detected in the presented cases. The AZF locus is assumed to contain the genes responsible for spermatogenesis in human. Deletions in these genes are thought to be involved in male infertility associated with azoospermia, oligozoospermia and/or both. AZF microdeletions and variations that are seen in infertile males suggest the need for molecular screening of such cases. Advance studies are also needed to detect of these variations and their relevance to male infertility before using assisted reproduction techniques in such cases.