Detection of Y chromosome microdeletions and mitochondrial DNA mutations in male infertility patients (original) (raw)
Related papers
Molecular Human Reproduction, 1996
Overall, -11% of men attending infertility clinics suffer unexplained oligo-or azoospermia. Cytogenetic observations of loss of the distal portion of the Y chromosome long arm (Yq) were found to be associated with disrupted spermatogenesis. The existence of a gene locus involved in the regulation of spermatogenesis, the azoospermia factor (AZF), was thus postulated. It is suggested that microdeletions, or mutations, at the AZF locus could result in impaired spermatogenesis in chromosomally normal men. In order to test this hypothesis we have carried out Y chromosome genetic screening of 100 oligo-or azoospermic 46XY patients. We have also assessed phenotype/genotype relationships in those patients whose infertility has an underlying genetic aetiology. Patients were screened by polymerase chain reaction (PCR) with a set of Y chromosomespecific sequence tagged sites (STS) for submicroscopic deletions of their Y chromosome. Our results show that as many as 8% of cases of unexplained male infertility may have an underlying genetic aetiology related to microdeletions in two specific regions of the Y chromosome. Positive results from such a screen will be important when deciding the suitability of a patient for assisted conception schemes such as intracytoplasmic sperm injection.
Role of Human Sperm Mitochondrial DNA in Infertility
2015
Sperm is the core of male fertility, which has to travel up to the fallopian tube for successful fertilization. Sperm motility depends on the electron transport chain producing ATPs in its mitochondria, which is a direct expression of the mitochondrial DNA (mtDNA) quality. Sperm motility is major determinant of fertility. It is already believed that mtDNA mutations are linked with infertility but the results are contradictory and previous researches are based on limited number of semen samples. Previous studies indicated a vacuum for more comprehensive study of sperm mtDNA from multiple aspects with sufficient number of carefully selected subjects to find more concrete findings. This case control study was designed on these hard facts to find association of sperm mtDNA deletions with fertility. We hypothesized that sperm mtDNA deletions have significantly associations with human male infertility. We collected 355 human semen samples (following WHO protocols), 74 samples normal contr...
International Journal of Reproductive BioMedicine (IJRM)
Background: Infertility affects about 15% of couples worldwide, and the male factor alone is responsible for approximately 50% of the cases. Genetic factors have been found to play important roles in the etiology of azoospermia and severe oligospermia conditions that affect 30% of individuals seeking treatment at infertility clinics. Objective: To determine the frequency of chromosomal abnormalities and Y chromosome microdeletion in infertile men. Materials and Methods: A total of 100 infertile men with abnormal semen parameters were included in this study from 2014 to 2018. Chromosomal analysis was carried out using standard G-banding using Trypsin Giemsa protocol. Multiplex polymerase chain reaction was used to determine the Y microdeletion frequency. Results: All participants were aged between 22 and 48 yr with a mean and standard deviation of 35.5 ± 5.1. Of the 100 subjects included in the study, three had Klinefelter syndrome-47,XXY, one had balanced carrier translocation- 46,X...
Male infertility and mitochondrial DNA
Biochemical and Biophysical Research Communications, 2004
The mitochondrial machinery plays a key role in the energy production and maintenance of spermatozoa motility. In this paper 200 idiopathic oligo-asthenozoospermic patients were classified on the basis of rapid progressive motility (''a'') and sperm concentration. Mitochondrial enzymatic activity was studied and correlated to the viability of sperm cells. Mitochondrial DNA purified from both motile and non-motile sperm of the same individuals was amplificated using PCR. Results suggested that only motile sperm have organelles functional in oxygen consumption, unequivocally demonstrating that motility depends on the mitochondrial activity. Mitochondrial DNA of oligo-asthenozoospermic patients seemed to present some defects that made DNA unavailable for amplification.
ZOOLOGICAL STUDIES-TAIPEI-, 2000
Yau-Huei Wei and Shu-Huei Kao (2000) Mitochondrial DNA mutation and depletion are associated with decline of fertility and motility of human sperm. Zoological Studies 39(1): 1-12. Sperm motility is one of the most important determinants of male fertility. In this review, we discuss recent findings that mutation and depletion of mitochondrial DNA (mtDNA) are associated with poor motility and diminished
2015
4To whom correspondence should be addressed Sperm motility is one of the major determinants of male fertility and is required for successful fertilization. In a previous study, we demonstrated that the occurrence and accumulation of the 4977 bp deletion of mitochondrial DNA (mtDNA) is associated with diminished fertility and motility of human spermatozoa. The possible relationship between multiple deletions of mtDNA and the decline of fertility and motility in human spermatozoa was further explored in 36 subjects including subfertile and infertile males in this study. Using long-range polymerase chain reaction (PCR), we confirmed the 4977 bp deletion and identified two novel deletions of 7345 and 7599 bp of mtDNA in the spermatozoa with poor motility. We used Percoll gradients to fractionate spermatozoa with differing motility, and then screened for two novel large-scale deletions of the mtDNA. The results showed that the ratio of the deleted mtDNA in the spermatozoa with poor motil...
Male infertility associated with multiple mitochondrial DNA rearrangements
Comptes Rendus de l'Académie des Sciences - Series III - Sciences de la Vie, 1997
Male sterility results from a number of characterized exogeneous or genetic dysficnctions preventing normaldifferentiation into mobilespermatozoa. This may now be overcome by intra cytophsmic sperm injection (ICSI). This practice does not require mobile, or even mature spermatozoa for in vitro fecondation. However, a firnctional respiratory chain, partly encoded by the mitocbondrial DNA (mtDNA), is requiredfor the mobility of the spermatozoa. We report the case of an infertile patient who wished to procreate. ICSI was proposed but be displayed multiple mtDNA deletions ofpossible nuclear origin in the spermatozoa and in the deltoid muscle. Even though mtDNA is maternally inherited, the possibility of a nuclear-driven mutation affecting the integrity of the mtDNA should be taken into account when Note pr&en& par Fran+ Gros Note remise le 7 avril 1997, accept& aprks revision k 1" juikt 1997 *Correspondence and reprints C. R. Acad. Sci. Paris, Sciences de la vie / Life Sciences 1997.320.629-636 629 P. Reynier et al. ICSI is to be pe$ormed. Together with recent genetic in vitro manipulations in mammals, our data point to the importance of studying the mtDNA structure in human spermatozoa, and the potential risks of these non-naturalpractices for procreation.
Molecular Human Reproduction, 1998
Sperm motility is one of the major determinants of male fertility and is required for successful fertilization. In a previous study, we demonstrated that the occurrence and accumulation of the 4977 bp deletion of mitochondrial DNA (mtDNA) is associated with diminished fertility and motility of human spermatozoa. The possible relationship between multiple deletions of mtDNA and the decline of fertility and motility in human spermatozoa was further explored in 36 subjects including subfertile and infertile males in this study. Using long-range polymerase chain reaction (PCR), we confirmed the 4977 bp deletion and identified two novel deletions of 7345 and 7599 bp of mtDNA in the spermatozoa with poor motility. We used Percoll gradients to fractionate spermatozoa with differing motility, and then screened for two novel large-scale deletions of the mtDNA. The results showed that the ratio of the deleted mtDNA in the spermatozoa with poor motility and diminished fertility were significantly higher than those in the spermatozoa with good motility and fertility. In addition, we found that the frequencies of the three large-scale deletions in the spermatozoa from patients with primary infertility and oligoasthenozoospermia were higher than those of the fertile males. Our findings suggest that mtDNA deletions may play an important role in some pathophysiological conditions of human spermatozoa.
Genetics of human male infertility
Infertility is defined as a failure to conceive in a couple trying to reproduce for a period of two years without conception. Approximately 15 percent of couples are infertile, and among these couples, male factor infertility accounts for approximately 50 percent of causes. Male infertility is a multifactorial syndrome encompassing a wide variety of disorders. In more than half of infertile men, the cause of their infertility is unknown (idiopathic) and could be congenital or acquired. Infertility in men can be diagnosed initially by semen analysis. Seminograms of infertile men may reveal many abnormal conditions, which include azoospermia, oligozoospermia, t e r a t oz o o s p e r m i a , a s t h e n oz o o s p e r m i a , necrospermia and pyospermia. The current estimate is that about 30 percent of men seeking help at the infertility clinic are found to have oligozoospermia or azoospermia of unknown aetiology. Therefore, there is a need to find the cause of infertility. The causes are known in less than half of these cases, out of which genetic or inherited disease and specific abnormalities in the Y chromosome are major factors. About 10-20 percent of males presenting without sperm in the ejaculate carry a deletion of the Y chromosome. This deleted region includes the Azoospermia Factor (AZF) locus, located in the Yq11, which is divided into four recurrently deleted non-overlapping subregions designated as AZFa, AZFb, AZFc and AZFd. Each of these regions may be associated with a particular testicular histology, and several candidate genes have been found within these regions. The Deleted in Azoospermia (DAZ) gene family is reported to be the most frequently deleted AZF candidate gene and is located in the AZFc region. Recently, a partial, novel Y chromosome 1.6-Mb deletion, designated "gr/gr" deletion, has been described specifically in infertile men with varying degrees of spermatogenic failure. The DAZ gene has an autosomal homologue, DAZL (DAZ-Like), on the short arm of the chromosome 3 (3p24) and it is possible that a defective autosomal DAZL may be responsible for the spermatogenic defect. The genetic complexity of the AZF locus on the long arm of the Y chromosome could be revealed only with the development of sequence tagged sites. Random attacks on the naked mitochondrial DNA (mtDNA) of sperm by reactive oxygen species or free radicals will inevitably cause oxidative damage or mutation to the mitochondrial genome with pathological consequences and lead to infertility in males. The key nuclear enzyme involved in the elongation and repair of mtDNA strands is DNA polymerase gamma, mapped to the long arm of chromosome 15 (15q25), and includes a CAG repeat region. Its mutation affects the adenosine triphosphate production. The introduction of molecular techniques has provided great insight into the genetics of infertility. Yet, our understanding of the genetic causes of male infertility remains limited.
European Journal of Obstetrics & Gynecology and Reproductive Biology, 2004
Objective: The main purpose of this study is to detect the frequency and type of both chromosomal abnormalities and Y chromosome microdeletions in patients with severe male factor infertility and fertile control subjects. The association between the genetic abnormality and clinical parameters was also evaluated. Methods: This study was carried out in 208 infertile and 20 fertile men. Results of 208 patients, 119 had non-obstructive azoospermia and 89 had severe oligoasthenoteratozoospermia (OAT). Seventeen out of 119 (14.3%) azoospermic patients and two out of 89 (2.2%) patients with OAT had Y chromosome microdeletions. In total, 19 cases with deletions were detected in 208 infertile men, with a frequency of 9.1%. The AZFc locus, mainly DAZ gene cluster was the most frequently deleted region. Five other cases with azoospermia (4.2%) and two cases with OAT (2.2%) had a chromosomal abnormality, with a total number of seven (3.4%). Including Y chromosome deletions and structural chromosome abnormalities, the rate of genetic abnormalities was 12.5% (26/208) in our patients. On the other hand, 20 men with proven fertility and fathers of five cases with microdeletions were genetically normal. Y chromosome deletions and chromosomal abnormalities were associated with various histological alterations in testis. Sertoli cell-only (SCO) syndrome and maturation arrest predominated in these cases, whereas hypospermatogenesis occurred more frequently in genetically normal patients. Conclusion: Various chromosomal abnormalities and deletions of Y chromosome can cause spermatogenic breakdown resulting in chromosomally derived infertility. All these findings strongly support the recommendation of genetic screening of infertile patients. #