AZF Deletions Research Articles

Screening and clinical phenotype analysis of microdeletions of azoospermia factor region on Y chromosome in 1011 infertile men

To investigate the prevalence and subtypes of microdeletions in azoospermia factor (AZF) region in infertile men from Sichuan in order to correlate genotypes with phenotypes. Multiplex-PCR was used to detect sequence tagged sites (STS) of AZF microdeletions in 1011 infertile men including 713 cases of non-obstructive azoospermia and 298 cases of severe oligospermia. The overall prevalence of microdeletions was 10.48% (106/1011), and the deletion rates were 11.08% (79/713) in non-obstructive azoospermia and 9.06% (27/298) in severe oligospermia. Complete AZFa or AZFb deletions were associated with azoospermia, whereas AZFc deletion (60.38%) was the most frequent deletion. The deletions were associated with variable spermatogenic phenotypes, and 37.50% of the patients with a deletion had sperms in the ejaculate. A mild decline in sperm concentration was found in two cases with partial AZFb deletion and one case with partial AZFb-c deletion. Deletions of the AZFc region were most commonly found in our patients. All cases with complete AZFa or AZFb deletions and a proportion of cases with AZFc deletion were associated with azoospermia. Our study has provided more insight into the genotype-phenotype correlation, and confirmed that Yq microdeletion screening has a significant value for the diagnosis for male infertility.

Molecular and cytogenetic studies of 101 infertile men with microdeletions of Y chromosome in 1,306 infertile Korean men

To determine the prevalence of Y chromosome microdeletions in infertile Korean men with abnormal sperm counts and to assess the clinical features and frequency of chromosomal abnormalities in Korean patients with microdeletions. A total of 1,306 infertile men were screened for Y chromosome microdeletions, and 101 of them had microdeletions. These 101 men were then retrospectively studied for cytogenetic evaluation, testicular biopsy and outcomes of IVF and ICSI. The overall prevalence of Y chromosome microdeletions in infertile men was 7.7% (101/1,306). Most microdeletions were in the AZFc region (87.1%), including deletions of AZFbc (24.7%) and AZFabc (8.9%). All patients with AZFa, AZFbc and AZFabc deletions had azoospermia, whereas patients with an AZFc deletion usually had low levels of sperm in the ejaculate or in the testis tissues. Chromosomal studies were performed in 99 men with microdeletions, 36 (36.4%) of whom had chromosomal abnormalities. Among the infertile men with Y chromosome microdeletions in this study, the incidence of chromosomal abnormality was 48.6% in the azoospermic group and 3.7% in the oligozoospermic group. Among the 69 patients with microdeletions and available histological results, 100.0% of the azoospermic group and 85.7% of the oligozoospermic group had histological abnormalities. The frequency of both chromosomal abnormalities and histological abnormalities was higher in the azoospermic group compared to the oligozoospermic group. Thirty-four ICSI cycles with either testicular (n = 14) or ejaculated spermatozoa (n = 20) were performed in 23 couples with men with AZFc microdeletion. Thirteen clinical pregnancies (39.4%) were obtained, leading to the birth of 13 babies. The study results revealed a close relationship between microdeletions and spermatogenesis, although IVF outcome was not significantly affected by the presence of the AZFc microdeletion. Nevertheless, Y chromosome microdeletions have the potential risk of being transmitted from infertile fathers to their offspring by ICSI. Therefore, before using ICSI in infertile patients with severe spermatogenic defects, careful evaluations of chromosomal abnormalities and Y chromosome microdeletions screening should be performed and genetic counseling should be provided before IVF-ET.

Early Versus Late Maturation Arrest: Reproductive Outcomes of Testicular Failure

There is a paucity of data characterizing infertile men with maturation arrest. We hypothesized that men with early stage maturation arrest could be clinically distinguished from men with late maturation arrest and would have worse reproductive outcomes. We retrospectively reviewed the records of all patients with nonobstructive azoospermia and cryptozoospermia who underwent testis mapping and sperm extraction from 2002 to 2009 and for whom histopathological findings were available. Patients had uniform maturation arrest if multiple biopsies revealed maturation arrest at the spermatogonia/spermatocyte (early maturation arrest) or the spermatid (late maturation arrest) stage. Clinical parameters and pregnancy outcomes of in vitro fertilization/intracytoplasmic sperm injection were examined. Statistical analysis consisted of univariate and multivariate analysis. Uniform maturation arrest was identified in 49 of 219 men (22.3%) undergoing testicular sperm extraction. On multivariate analysis men with maturation arrest had significantly larger testes (p=0.01), decreased follicle-stimulating hormone (p=0.05) and more detectable genetic abnormalities (p=0.01) than men with other histopathological conditions. Men with late maturation arrest had decreased follicle-stimulating hormone (p=0.02), increased testosterone (p=0.03) and a higher sperm retrieval rate at testicular sperm extraction (p=0.01) than men with early maturation arrest. Predictors of successful sperm retrieval were larger testes, cryptozoospermia, late maturation arrest and hypospermatogenesis (each p≤0.05). Pregnancy outcomes for men with maturation arrest were not significantly different from those for men with other histopathological conditions. Maturation arrest is a common, diverse histopathological subtype of severe male infertility. Compared to men with late maturation arrest those with early maturation arrest have increased follicle-stimulating hormone, decreased testosterone and a decreased probability of mature spermatozoa. In vitro fertilization/intracytoplasmic sperm injection outcomes were similar when spermatozoa were discovered during testicular sperm extraction.

Primary male infertility in Izmir/Turkey: a cytogenetic and molecular study of 187 infertile Turkish patients

To detect somatic cytogenetic abnormalities and AZF microdeletions in a sample of 187 Turkish infertile men to determine the frequencies and the characteristics of our primary male infertility data in order to perform appropriate genetic counseling. This study included 187 infertile men. Chromosomal studies and screening of AZF deletions was performed by multiplex polymerase chain reaction (PCR) analysis using the Y Chromosome Deletion Detection System. Cytogenetic study revealed chromosomal abnormality in 9 subjects (4.8%). In remaining 178 subjects, 7 subjects (3.93%) were detected to have Y chromosome microdeletions. The AZFc region was the most frequently involved region in microdeletion process in affected subjects. All subjects having microdeletion were azoospermic Cytogenetic and molecular study should be performed to obtain reliable genetic information for the genetic counseling of primary infertile man. Y chromosome microdeletion diagnosis is useful in decision making for assisted reproductive technics.

Aberrations in Pseudoautosomal Regions (PARs) Found in Infertile Men with Y-Chromosome Microdeletions

The pseudoautosomal regions (PARs) of the Y-chromosome undergo meiotic recombination with the X-chromosome. PAR mutations are associated with infertility and mental and stature disorders. The aim of the study was to determine whether men with Y-chromosome microdeletions have structural defects in PARs. Eighty-seven infertile men with Y-chromosome microdeletions and 35 controls were evaluated for chromosomal rearrangements using commercial or custom (X- and Y-chromosome) array comparative genomic hybridization or by quantitative PCR of selected PAR genes. Multisoftware-defined chromosomal gains or losses were validated by quantitative PCR and FISH. Array comparative genomic hybridization confirmed the AZF deletions identified by multiplex PCR. All men with Y-chromosome microdeletions and an abnormal karyotype displayed PAR abnormalities, as did 10% of men with Y-chromosome microdeletions and a normal karyotype. None of the control subjects or infertile men without Y-chromosome microdeletions had PAR duplications or deletions. SHOX aberrations occurred in 14 men (nine gains and five losses); four were short in stature (<10th percentile), and one was tall (>95th percentile). In contrast, the height of 23 men with Y-chromosome microdeletions and normal PARs was average at 176.8 cm (50th percentile). Y-chromosome microdeletions can include PAR defects causing genomic disorders such as SHOX, which may be transmitted to offspring. Previously unrecognized PAR gains and losses in men with Y-chromosome microdeletions may have consequences for offspring.

Y chromosome microdeletions are not associated with spontaneous recurrent pregnancy loss in a Sinhalese population in Sri Lanka

Many advances have been made in reproductive medicine, yet the spontaneous loss of a pregnancy remains the most common complication of pregnancy. The aetiology of spontaneous recurrent pregnancy loss (RPL) is multifactorial. Y chromosome microdeletions are found in ∼7% of men with low sperm counts and, compared with the general population, a higher frequency of spontaneous pregnancy loss occurs in infertile couples. The current study was designed to examine whether Y chromosome microdeletions were associated with RPL in a Sinhalese population in Sri Lanka. The subjects were 76 male partners of couples where the female partner had experienced three or more RPLs. One hundred and twenty random males from the general population were also analysed as a control group. DNA extracted from peripheral blood was tested for Y chromosome microdeletions in the azoospermic factor (AZF), AZFa, AZFb, AZFc regions using a multiplex PCR amplification system. Partial deletions within the AZFc region were also tested. None of the men (76 with RPL, and the 120 controls) had any microdeletions in the AZFa, AZFb, AZFc regions or partial deletions in the AZFc region. Y chromosome microdeletions do not appear to be important in the aetiology of RPL in this population in Sri Lanka.

Clinical data and parenthood of 63 infertile and Y-microdeleted men

To collect follow-up data for infertile men with Y microdeletion. Retrospective, observational survey. Multicenter IVF units associated with genetics laboratories. Sixty-three patients with Y microdeletion. Karyotype analysis, Y microdeletion screening, and assisted reproductive technology. Medical history, karyotype, nature of the AZF deletion, semen parameters, testis biopsy results, choice of assisted reproductive technology, and results of intracytoplasmic sperm injection (ICSI). Abnormal karyotypes were found in 8 men (12.7%), who were azoospermic except 1. Of these 8 men, 5 presented a combined AZFb+c deletion, and 3 had a deletion in AZFc only. Most men (39 of 63) were azoospermic, 3 were cryptoazoospermic, and 19 had extreme oligozoospermia (sperm concentration </=1.10(6)/mL). Sperm concentration above 1.10(6)/mL was found for 2 men (3.1%). A testis biopsy was performed in 27 azoospermic men, resulting in positive sperm extraction in 6 cases. To date, 42 ICSI cycles with either testicular (n = 5) or ejaculated spermatozoa (n = 37) have been carried out in 23 couples with male partners with AZFc deletion. Eighteen clinical pregnancies were obtained, leading to the birth of 14 babies. Donor insemination had been chosen by 28 couples, leading to the birth of 9 children. Karyotype analysis should be systematically performed in Y microdeleted men. Intracytoplasmic sperm injection can be offered to half of AZFc-deleted patients, providing real opportunities to have a child.

Massive deletion in AZFb/b+c and azoospermia with Sertoli cell only and/or maturation arrest

Recent studies have revealed that AZF deletion in Y chromosome is the most common known molecular genetic cause of spermatogenetic failure leading to male infertility. Characteristics of AZFa, AZFb and AZFc deletions and their association with spermatogenic impairment have been reported in a large number of populations. However, the distributions of those larger deletions resulted from P5/proximal-P1, P5/distal-P1 and P4/distal-P1 recombinations are still unclear as the literature on their frequencies is limited, and the contribution of these deletions to spermatogenetic failure remain to be confirmed by population studies. In this study, we investigated such massive deletions in 387 idiopathic azoospermic, 269 oligozoospermic patients and 315 men with normal spermatogenesis using 21 AZFb/c specific sequence-tagged sites. As a result, nine uninterrupted massive deletions were observed exclusively in men with azoospermia caused by either Sertoli cell only (SCO) or maturation arrest (MA). Prevalence of the deletion was 2.33%, in which five deletions arose from non-allelic homologous recombination between the palindromes P5 and P1 and two between P4 and P1. In other two deletions, novel proximal breakpoints in the interval region between P4 and P3 were observed. Our findings strongly support that the massive deletions in the AZFb or AZFb+c regions are important genetic causes of SCO and/or MA resulting in azoospermia and, besides the P5/proximal-P1, P5/distal-P1 and P4/distal-P1 deletions there may be other massive deletions in these regions resulting in severe spermatogenic impairment.

Detection of Y chromosome microdeletions in semen of patients with azoospermia: study of 241 cases

To set up a simple and reliable method to screen Y chromosome microdeletions in semen of azoospermic patients, and to explore the incidence and loci of Y chromosome microdeletions in Chinese azoospermia. Two hundred and forty-one semen samples, 51 containing blood, were collected from 241 Chinese azoospermic patients. 45 normal semen samples and 1 anticoagulated blood sample from female were used as controls. DNA was quickly abstracted by incubating the cells with a lysis buffer containing polymerase chain reaction (PCR) buffer and protease K, and was used to detect the deletion of 15 kinds of sequence tagged site (STS) distributed in AZFa, AZFb, and AZFc by 4 sets of multiplex PCR. Agarose electrophoresis was used to observe and compare the PCR products from the semen samples and their corresponding blood samples, and the PCR products from 1 semen sample were confirmed by sequencing. All multiplex PCR reactions were amplified successfully. The sequencing of the PCR products from the semen samples confirmed the PCR reactions. No microdeletion was detected in the 45 normal semen samples. Microdeletion was found in 26 out of the 241 semen samples of azoospermic patients (10.8%): 2 patients (7.7%) had the deletions located in AZFa, 2 patients (7.7%) in AZEb, 3 patients (11.5%) in both AZFb + AZFc, and other 19 patients (73.1%) in AZFc. The detection results of the blood samples were completely consistent with those of the semen samples. The STS deletion recommended by European Academy of Andrology (EAA) and European Molecular Genetics Quality Network (EMQN) were all found in these 26 cases. The semen samples of azoospermic patients present a convenient, reliable, and noninvasive substitute for blood in screening of Y chromosome microdeletions, and can be employed in study and clinical examination. The EAA/EMQN recommendations allow the detection of complete AZF deletions in Chinese azoospermia.

Clinical consequences of microdeletions of the Y chromosome: the extended Münster experience

A total of 3179 patients were screened for Y-chromosome microdeletions and 821 patients for partial AZFc deletions. Thirty-nine Y-chromosomal microdeletions were found (2.4% of men with <1 × 10 6/ml spermatozoa): two AZFa, two AZFb, one AZFbc, one partial AZFb, one partial AZFb+c and 32 AZFc ( b2/b4). Partial AZFc deletions were found in 45 patients (5.5%), mostly gr/gr deletions ( n = 28). In patients with AZFc deletion, azoospermia was found in 53.1% and sperm concentrations of mostly <0.1 × 10 6/ml were found in 46.9%. Semen analyses and FSH measurements showed no trend over time. Elongated spermatids were seen in 6/15 AZFc patients and bilateral Sertoli cell-only was found in 4/15. Testicular sperm extraction (TESE) was attempted in 10 patients and spermatozoa were found in six. Compared with infertile men matched by sperm concentration, no differences in hormonal and seminal parameters could be found in patients with AZFc or gr/gr deletions. It is concluded that: (i) frequency of AZF deletions in Germany is much lower than in other countries; (ii) AZFc deletions are associated with severe disturbances of spermatogenesis and TESE is not possible in half of these patients; (iii) AZFc and gr/gr deletions are not associated with any clinical diagnostic parameter; (iv) and no trend is apparent over time.

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.

AZF microdeletions and partial deletions of AZFc region on the Y chromosome in Moroccan men

To evaluate for the first time the frequency of Y chromosome microdeletions and the occurrence of the partial deletions of AZFc region in Moroccan men, and to discuss the clinical significance of AZF deletions. We screened Y chromosome microdeletions and partial deletions of the AZFc region of a consecutive group of infertile men (n = 149) and controls (100 fertile men, 76 normospermic men). AZFa, AZFb, AZFc and partial deletions of the AZFc region were analyzed by polymerase chain reaction (PCR) according to established protocols. Among the 127 infertile men screened for microdeletion, four subjects were found to have microdeletions: two AZFc deletions and two AZFb+AZFc deletions. All the deletions were found only in azoospermic subjects (4/48, 8.33%). The overall AZFc deletion frequency was low (4/127, 3.15%). AZF microdeletions were not observed in either oligoasthenoteratozoospermia (OATS) or the control. Partial deletions of AZFc (gr/gr) were observed in a total of 7 of the 149 infertile men (4.70%) and 7 partial AZFc deletions (gr/gr) were found in the control group (7/176, 3.98%). In addition, two b2/b3 deletions were identified in two azoospermic subjects (2/149, 1.34%) but not in the control group. Our results suggest that the frequency of Y chromosome AZF microdeletions is elevated in individuals with severe spermatogenic failure and that gr/gr deletions are not associated with spermatogenic failure.

Study of azoospermia factor-a deletion caused by homologous recombination between the human endogenous retroviral elements and population-specific alleles in Japanese infertile males

To evaluate the relationship between the status of homologous recombination and population-specific alleles in infertile Japanese males with azoospermia factor (AZF)-a deletions and to characterize the clinical features of these patients. Retrospective deletion study in infertile Japanese men. University hospital and reproductive clinic. A total of 931 consecutive patients visiting a male-infertility clinic were genetically evaluated. Patients were analyzed for Y-chromosomal microdeletions and the breakpoints of intrachromosomal homologous recombination of human endogenous retrovirus (HERV) 15qy; in addition, Y-haplogroup typing on the basis of polymerase chain reaction also was performed. Endogenous retroviruses contribute to the evolution of the host genome and can be associated with disease. Presence or absence of appropriately sized polymerase chain reaction products. Four cases of AZFa deletions were found. All patients with AZFa deletions had an azoospermia and breakpoints in the ID2 region of HERV15qy. Three of the four cases were derived from Y-haplogroup D2b. Testicular sperm extraction procedures were performed in three of these four patients, and elongated spermatids were recovered in two. However, no pregnancies were successfully achieved. Y-haplotype D2b, specific for some Japanese clade, may be associated with HERV breakpoints that lead to intrachromosomal homologous recombination. From the clinical point of view, the testicular sperm extraction procedure is not applicable to males with complete AZFa deletions.

Fine mapping of re-arranged Y chromosome in three infertile patients with non-obstructive azoospermia/cryptozoospermia

Cytogenetically detectable aberrations of the Y chromosome, such as isodicentrics, rings or translocations are sometimes associated with male non-obstructive infertility. This report presents a detailed analysis of the clinical, cytogenetic and molecular data in three patients with a re-arranged Y chromosome. Patients A and B were azoospermic, whereas patient C was cryptozoospermic. All had a somatic mosaic karyotype including a population of 45,X cells and a cell line with a re-arranged Y chromosome. A molecular and FISH analysis of their re-arranged Y was undertaken, which specifically focussed on the presence of the AZFa, b and c regions. The AZFa region was present in all the three patients. The AZFb and AZFc regions were absent in patients A and B, whereas, in patient C, the distal part of AZFb and the whole AZFc region were deleted. Moreover, in this patient, the AZF FISH analysis revealed a mosaicism for the size of the AZF deletion within the re-arranged Y, suggesting a progressive enlargement of the deletion during cell mitotic divisions. This investigation allowed not only a more precise description of the abnormal Y, but also shed light on how this re-arrangement could be involved in the infertility phenotype.

Analysis of sex chromosome abnormalities using X and Y chromosome DNA tiling path arrays

Background: Array comparative genomic hybridisation is a powerful tool for the detection of copy number changes in the genome. Methods: A human X and Y chromosome tiling path array was...

Molecular and Clinical Characterization of Y Chromosome Microdeletions in Infertile Men: A 10-Year Experience in Italy

An explosive growth in Y chromosome long arm (Yq) microdeletion testing demand for male infertility occurred in the past few years. However, despite the progresses in the biology of this chromosome, a number of molecular and clinical concerns are not supported by definitive data. The objective was to provide information on the type and prevalence of microdeletions in infertile males, indication for testing, genotype-phenotype correlation, sperm aneuploidies, and genetic counseling. We performed a prospective study from January 1996 to December 2005 in an academic clinic. We studied 3073 consecutive infertile men, of which 625 were affected by nonobstructive azoospermia and 1372 were affected by severe oligozoospermia. Ninety-nine patients with microdeletions are described here. Yq microdeletions, seminal analysis, reproductive hormones, testicular cytology/histology, and sperm sex chromosomes aneuploidies were used as outcome measures. The prevalence of microdeletions was 3.2% in unselected infertile men, 8.3% in men with nonobstructive azoospermia, and 5.5% in men with severe oligozoospermia. Only 2 of 99 deletions were found in men with more than 2 million sperm/ml. No clinical data are useful to identify a priori patients with higher risk of Yq microdeletions. Most deletions are of the AZFc-b2/b4 subtype and are associated with variable spermatogenic phenotype, with sperm present in 72% of the cases. Complete AZFa and AZFb (P5/Proximal P1) deletions are associated with Sertoli cell-only syndrome and alterations in spermatocyte maturation, respectively, whereas partial deletions in these regions are associated with milder phenotype and frequent presence of sperm. Men with AZFc-b2/b4 deletions produce a higher percentage of sperm with nullisomy for the sex chromosomes and XY-disomy. This extensive clinical research expands the knowledge on genotype-phenotype relationships and confirms that the identification of Yq microdeletions has significant diagnostic and prognostic value, adding useful information for genetic counseling in these patients.

A frequent Y chromosome b2/b3 subdeletion shows strong association with male infertility in Han-Chinese population

Azoospermia factor c (AZFc) subdeletions were reported to be significant risk factors for spermatogenesis. In this study, we assessed the occurrence of classical AZF deletions and AZFc subdeletions and their impact on male infertility in a Han-Chinese population. This study analysed a population of 699 subjects, including 451 idiopathic infertile patients with a range of fertility disorders and 248 fertile controls, using a retrospective design. Deletions were identified by multiplex PCR. The prevalence and phenotypes of the classical AZF deletions were similar to previous studies. Subdeletions of the AZFc region in patients showed similar overall frequencies in all sperm concentration categories of gr/gr (7.0%) and b2/b3 (8.9%). For controls, these subdeletions were also found with a prevalence of gr/gr (7.7%) and b2/b3 (3.2%). b1/b3 deletions were not found either in the patients or in the controls. Our data showed a higher frequency of deletion events in this Han-Chinese population than in populations elsewhere in the world. The classical AZF deletions were the primary genetic factors for spermatogenic failure, while no significant association was found for AZFc subdeletions with sperm concentration. However, the b2/b3 subdeletion was significantly associated with idiopathic male infertility (odds ratio, 2.93; 95% confidence interval 1.34-6.39) (P = 0.005), indicating a potential impairment of male fertility.

Microarray detection of Y chromosome deletions associated with male infertility

Array-comparative genomic hybridization (CGH) has emerged as a powerful new molecular tool for the high-resolution analysis of copy-number variation and breakpoint analysis. In this study, array-CGH was used to analyse known Yq deletions associated with male infertility. A microarray platform encompassing probes for chromosomes 13, 14, 21, X and Y was developed in-house and was used to detect different Yq deletion types. The successful application of this array for the detection of Yq deletions involving either the AZFb or AZFc region was demonstrated. Partial and complete AZF deletions were correctly detected in 13 patients with Yq deletions previously identified by multiplex polymerase chain reaction (PCR). This study demonstrates that array-CGH may be an alternative approach to multiplex PCR for the diagnosis of known Yq deletions and potentially a useful tool for the discovery of other Y chromosome deletions/polymorphisms associated with defective spermatogenesis.

Polymorphismes du chromosome Y et fertilité masculine

Molecular anomalies of the Y chromosome leading to male infertility are mainly microdeletions of the long arm of the Y chromosome. Three recurrently deleted portions of the long arm are the AZFa, AZFb and AZFc (AZF: Azoospermia Factor) regions. Complete deletions of the AZFc region are found in 10% of cases of severe male infertility. In addition to the AZF deletions, certain classes of Y chromosome (haplogroups) may also predispose to male infertility and could be transmitted to future male descents by various Assisted Reproductive Techniques (ART). Since the first discovery of microdeletions, the sequence of the Y chromosome has become available, revealing the mechanisms underlying deletion formation and also resulting in a coherent screening strategy. Recently, partial deletions of the AZF regions have been described. The significance of these deletions in the clinical context remains to be defined.

Comparative Study of AZF Deletions and TSPY Gene Variation in Czech and Indian Infertile Men

The human Y chromosome harbours genes that are essential for spermatogenesis. Most of these genes lie in the male-specific region (MSY) of Y chromosome. Microdeletions of AZF within the MSY have been reported in infertile men. Widely different frequencies of such deletions (0-55%) have been reported from different populations. TSPY is another gene located in the MSY region that plays a significant role in spermatogenesis. It is a multi-copy gene but the role its gene copy numbers play in infertility is not yet evaluated. The present study was undertaken on infertile men from Czech Republic and India to ascertain the relative and comparative role of AZF deletions and of TSPY copy numbers.