Frequency Of Disomy For Chromosomes Research Articles

Aneuploidy frequency in spermatozoa of Egyptian men with normal and abnormal semen parameters using fluorescencein situhybridisation

Chromosome anomalies were suggested to be more frequent in infertile males so our case-control study aimed at evaluating the incidence of spermatic aneuploidies in forty males with severe oligoasthenoteratozoospermia (OAT) and comparing it with that in another forty males having normal semen parameters. Semen samples were collected and analysed in the Clinical Pathology Department according to criteria of the World Health Organization (WHO laboratory manual for the examination and processing of human semen, 2010, WHO Press). Fluorescence in situ hybridisation (FISH) was performed on decondensed spermatozoa from fresh semen ejaculates, using dual coloured chromosome-specific DNA probes labelled with fluorochromes to study sperm aneuploidies in chromosomes 13, 21, X and Y. There was no statistical significant difference between cases and controls regarding disomy frequencies for chromosomes 13, 21 or both combined. However, 13, 21 diploidy frequency was significantly higher among OAT cases. Regarding chromosomes X and Y, both cases and controls showed similar results for disomy/diploidy frequency for both chromosomes; however, there was a statistical significant increase in YY disomy/diploidy frequency among OAT patients. X chromosome-bearing spermatozoa were found to be significantly higher among controls. Patients with severe OAT have a higher total sperm aneuploidy rate, regarding chromosomes 13, 21, X and Y but without a statistical significant difference.

Detection of aneuploidy rate for chromosomes X, Y and 8 by fluorescence in-situ hybridization in spermatozoa from patients with severe non-obstructive oligozoospermia

To evaluate the frequency of sperm nuclei disomy for chromosomes 8, X, and Y in patients with severe non-obstructive oligozoospermia and to assess possible correlations between sperm nuclei aneuploidy and semen parameters or a particular clinical phenotype. The sperm aneuploidy rate for chromosomes X, Y, and 8 were assessed in 16 infertile men with severe non-obstructive oligozoospermia and 7 healthy men with normal semen parameters. The frequency of sperm aneuploidy was compared between several patients groups according to their clinical and biological factors. The total rate of chromosomally abnormal spermatozoa was significantly higher in patients with severe oligozoospermia compared to control group (P < 0.001). A significant relationship was found between the age of patients, sperm concentration, and morphology and the mean rate of sex chromosomes disomy. In addition to the low sperm count (<5 × 10(6)/ml), an elevated FSH level and an exposed to an elevated temperature are two major predictive factors leading to the production of higher numbers of chromosomally abnormal gametes. Patients with severe oligozoospermia, who are potential candidates for assisted reproduction technology, presented a high level of sex numerical chromosome abnormalities, and consequently are at high risk of chromosome abnormalities in their offspring.

An increased incidence of autosomal aneuploidies in spermatozoa from a patient with Klinefelter’s syndrome

Objective To determine whether there is an increased incidence of autosomal aneuploidies in spermatozoa from a subject with nonmosaic Klinefelter’s syndrome. Design Analysis of sperm nuclei by fluorescence in situ hybridization. Setting Hospital-based laboratory for reproductive biology. Patient(s) A patient with Klinefelter’s syndrome and a 46,XY fertile man were analyzed. Intervention(s) The sperm samples were prepared for fluorescence in situ hybridization. Main outcome measure(s) The disomy frequencies for chromosomes 7, 9, 13, 18, and 21 and sex chromosomes were determined using fluorescence in situ hybridization. Result(s) Significant differences were found in the frequency of disomy for chromosomes 13, 18, and 21 between the patient and a normospermic control. No significant differences were observed for chromosomes 7 and 9. The frequencies of gonosomal abnormalities and diploid spermatozoa were also significantly increased in the patient. Conclusion(s) Our results indicate that there is an increased incidence of autosomal aneuploidies for chromosomes 13, 18, and 21 in the spermatozoa from the patient with Klinefelter’s syndrome than in the general population. Furthermore, most of the studies have also shown an increased frequency of autosomal aneuploidy in the spermatozoa from 46,XY males with oligozoospermia or oligoasthenoteratozoospermia. Thus, the offspring of the patients with Klinefelter’s born by intracytoplasmic sperm injection may be at higher risk of autosomal aneuploidy due to oligoasthenoteratozoospermia.

Chromosome abnormalities in sperm from infertile men with asthenoteratozoospermia.

Research over the past few years has clearly demonstrated that infertile men have an increased frequency of chromosome abnormalities in their sperm. These studies have been further corroborated by an increased frequency of chromosome abnormalities in newborns and fetuses from pregnancies established by intracytoplasmic sperm injection. Most studies have considered men with any type of infertility. However, it is possible that some types of infertility have an increased risk of sperm chromosome abnormalities, whereas others do not. We studied 10 men with a specific type of infertility, asthenozoospermia (poor motility), by multicolor fluorescence in situ hybridization analysis to determine whether they had an increased frequency of disomy for chromosomes 13, 21, XX, YY, and XY, as well as diploidy. The patients ranged in age from 28 to 42 yr (mean 34.1 yr); they were compared with 18 normal control donors whose ages ranged from 23 to 58 yr (mean 35.6 yr). A total of 201 416 sperm were analyzed in the men with asthenozoospermia, with a minimum of 10 000 sperm analyzed per chromosome probe per donor. There was a significant increase in the frequency of disomy in men with asthenozoospermia compared with controls for chromosomes 13 and XX. Thus, this study indicates that infertile men with poorly motile sperm but normal concentration have a significantly increased frequency of sperm chromosome abnormalities.

Aneuploid spermatozoa in infertile men: Teratozoospermia

We and others have demonstrated that infertile men who are candidates for intracytoplasmic sperm injection (ICSI) have an increased frequency of chromosomal abnormalities in their sperm. Reports based on prenatal diagnosis of ICSI pregnancies have confirmed the increased frequency of chromosomal abnormalities in offspring. Most studies to date have lumped various types of infertility together. However, it is quite likely that some subsets of infertility have an increased risk of sperm chromosomal abnormalities whereas others do not. We have studied nine men with severe teratozoospermia (WHO, 1992 criteria, 0-13% morphologically normal forms) by multicolour fluorescence in situ hybridisation (FISH) analysis to determine if they have an increased frequency of disomy for chromosomes 13, 21, XX, YY, and XY, as well as diploidy. All of the men also had aesthenozoospermia (< 50% forward progression) but none of the men had oligozoospermia (<20 x 10(6) sperm/ml). The patients ranged in age from 20 to 49 years (mean 33.2 years) in comparison to 18 normal control donors who were 23 to 58 years (mean 35.6 years). The control donors had normal semen parameters and no history of infertility. A total of 180,566 sperm were scored in the teratozoospermic men with a minimum of 10,000 sperm analyzed/donor/chromosome probe. There was a significant increase in the frequency of disomy in teratozoospermic men compared to controls for chromosomes 13 (.23 vs.13%), XX (.13 vs.05%), and XY (.50 vs.30%) (P <.0001, 2-tailed Z statistic). This study indicates that men with teratozoospermia and aesthenozoospermia but with normal concentrations of sperm have a significantly increased frequency of sperm chromosomal abnormalities.

Acrocentric chromosome disomy is increased in spermatozoa from fathers of Turner syndrome patients.

The aim of the present study was to investigate whether there was an increase of aneuploidy in the sperm from fathers of Turner syndrome patients of paternal origin who, in a previous study, showed an elevated incidence of XY meiotic nondisjunction. Sperm disomy frequencies for chromosomes 4, 13, 18, 21 and 22 were assessed by fluorescence in situ hybridisation in four of these individuals. As a group, the Turner syndrome fathers showed a general increase in disomy frequencies for chromosomes 13, 21 and 22, with a statistically significant increase in disomy frequencies for chromosomes 13 and 22 in one of the fathers and for chromosome 21 in two of them. Data from a previous work carried out by us in two fathers of Down syndrome patients of paternal origin also revealed increased sperm disomy frequencies for chromosomes 13, 21 and 22. Pooled as one group, these six fathers of aneuploid offspring of paternal origin had a statistically significant increase in the frequency of nondisjunction for these chromosomes with respect to control individuals. Our findings indicate that there may be an association between fathering aneuploid offspring and increased frequencies of aneuploid spermatozoa. Such increases do not seem to be restricted to the chromosome pair responsible for the aneuploid offspring. Acrocentric chromosomes and other chromosome pairs that usually show only one chiasma during meiosis seem to be more susceptible to malsegregation.

Numerical chromosome abnormalities in the spermatozoa of the fathers of children with trisomy 21 of paternal origin: generalised tendency to meiotic non-disjunction

The purpose of this study was the evaluation of aneuploidy frequencies in the spermatozoa of two fathers (DP-4 and DP-5) who had children with Down syndrome (DS) of paternal origin and in whom a previous sperm analysis by fluoresence in situ hybridisation (FISH) had suggested a generalised tendency to meiotic non-disjunction. Sperm samples were simultaneously hybridised with FISH probes for chromosomes 4, 13 and 22. Disomy frequencies for each of the chromosomes and diploidy frequencies were compared with data obtained from nine control donors. Both DS fathers had a statistically significant increase in the frequency of disomy for chromosomes 13 and 22. DP-5 also had an increased frequency of diploid spermatozoa. Our data suggest that the two DS fathers have a generalised susceptibility to meiotic non-disjunction and that acrocentric chromosomes seem to be more sensitive to such disturbance in the meiotic process.

Chromosome analysis of spermatozoa extracted from testes of men with non-obstructive azoospermia.

Infertile men with azoospermia now have the possibility of fathering children by testicular sperm extraction combined with intracytoplasmic sperm injection. However, there are concerns about the risk of chromosomal abnormalities in their spermatozoa. We have studied aneuploidy frequencies for chromosomes 13, 21, X and Y by multicolour fluorescence in-situ hybridization (FISH) in testicular spermatozoa extracted from three men with non-obstructive azoospermia. The men were 34-37 years of age and had normal follicle-stimulating hormone (FSH) concentrations and normal 46,XY somatic karyotypes. A total of 3324 spermatozoa was analysed. The infertile patients had an elevated frequency of disomy for chromosomes 13, 21, XY disomy compared to controls but none of these reached statistical significance. Also there was no significant difference in the sex ratio or the frequency of diploidy in azoospermic patients compared to normal control donors. This first report on chromosomal aneuploidy in spermatozoa extracted from testes of patients with non-obstructive azoospermia suggests that some azoospermic men do not have a substantially increased risk of chromosomally abnormal spermatozoa.

Chromosome analysis of spermatozoa extracted from testes of men with non-obstructive azoospermia

Infertile men with azoospermia now have the possibility of fathering a pregnancy by testicular sperm extraction combined with intracytoplasmic sperm injection. However, there are concerns about the risk of chromosomal abnormalities in their sperm. We have studied aneuploidy frequencies for chromosomes 13, 21, X and Y by multicolour fluorescence in situ hybridization (FISH) analysis in testicular spermatozoa extracted from three men with nonobstructive azoospermia. The men were 34-37 years of age and had normal FSH levels and normal 46, XY somatic karyotypes. A total of 3324 spermatozoa were analyzed. The infertile patients had an elevated frequency of disomy for chromosomes 13, 21, XY disomy compared to controls but none of these reached statistical significance. Also there was no significant difference in the sex ratio or the frequency of diploidy in azoospermic patients compared to normal control donors. This first report on chromosomal aneuploidy in spermatozoa extracted from testes of patients with nonobstructive azoospermia suggests that some azoospermic men do not have a substantially increased risk of chromosomally abnormal spermatozoa.

Screening for abnormalities of chromosomes X, Y, and 18 and for diploidy in spermatozoa from infertile men participating in an in vitro fertilization-intracytoplasmic sperm injection program

Objective: To evaluate the frequency of disomy (for chromosomes X, Y, and 18) and of diploidy in the spermatozoa of infertile men undergoing intracytoplasmic sperm injection (ICSI). Design: Prospective analysis of sperm nuclei by fluorescence in situ hybridization (FISH). Setting: University-affiliated IVF-ICSI program. Patient(s): Semen samples from 19 patients participating in an IVF-ICSI program. Intervention(s): Semen samples were analyzed and prepared for FISH. Main Outcome Measure(s): Semen parameters were evaluated. The frequency of disomy for chromosomes X, Y, and 18 and the frequency of diploidy were analyzed by FISH. Result(s): A total of 9,373 spermatozoa from 19 infertile patients were analyzed and compared with spermatozoa from a control group of 5 healthy men. No differences in the frequency of disomy 18 were found, but statistically significant differences in the incidence of sex chromosome disomy and of diploidy were observed. Conclusion(s): The study of sperm nuclei by FISH is useful to improve genetic counseling in infertile patients selected for ICSI.

Nondisjunction in human sperm: comparison of frequencies in acrocentric chromosomes

Acrocentric chromosomes may be particularly predisposed to nondisjunction because of the frequency of trisomy for these chromosomes in human spontaneous abortions and liveborns. Studies of aneuploidy in human sperm have provided data on only a few acrocentric chromosomes, with evidence that chromosome 21 has a significantly increased frequency of disomy. To determine whether other acrocentric chromosomes have a higher frequency of nondisjunction or if chromosome 21 is anomalous, disomy frequencies for chromosomes 13 and 22 were studied by fluorescence in situ hybridization (FISH) analysis of 51,043 sperm nuclei from five normal men for whom the frequency of disomy for chromosomes 15 and 21 was known. The mean frequency of disomy for chromosome 13 (0.19%) did not differ significantly from that for other autosomes; however, the frequency of disomy 22 (1.21%) was significantly elevated (P < 0.001, Mantel-Haenszel χ² test). The G-group chromosomes (Nos. 21 and 22) also showed a significantly increased frequency of disomy (0.75%) compared to acrocentric D-group chromosomes (viz., chromosomes 13 and 15; 0.15%) (P < 0.001, Mantel-Haenszel χ² test) and other autosomes (chromosomes 1, 2, 4, 9, 12, 13, 15, 16, 18, and 20; 0.13%) studied in the same men (P < 0.001, Mantel-Haenszel χ² test).

Donor age and the frequency of disomy for chromosomes 1, 13, 21 and structural abnormalities in human spermatozoa using multicolour fluorescence in-situ hybridization.

The purpose of this study was to determine if a donor age effect exists for the frequency of aneuploidy and other chromosome abnormalities in human spermatozoa. Sperm samples were collected from 18 healthy men from the general population. Each individual belonged to one of six age groups (20-24, 25-29, 30-34, 35-39, 40-44, > or = 45 years) with three men in each group. Two multicolour fluorescence in-situ hybridizations were performed on spermatozoa from each donor using probes for chromosomes 13 and 21, and two chromosome 1-specific probes allowed for detection of duplications and deletions as well as disomy of chromosome 1. The abnormality frequencies and the Pearson correlation coefficients were calculated to determine if a relationship existed between donor age and the frequency of chromosome abnormalities in spermatozoa. A statistically significant association with donor age was detected for the frequency of acentric fragments of chromosome 1 (P < 0.05).

Estimation of aneuploidy levels for 8, 15, 18, X and Y chromosomes in 97 human sperm samples using fluorescence in situ hybridization

Objective: To estimate the mean frequency of aneuploidy levels of chromosomes 8, 15, 18, X, and Y in human sperm, while minimizing the effect of individual factors by analyzing sperm samples from a large set of patients. Design: Prospective randomized analysis of sperm nuclei by fluorescence in situ hybridization. Setting: University-based laboratory for reproductive biology. Patient(s): One hundred two patients with a large distribution of sperm parameters, randomly selected from volunteers who had presented seeking a semen analysis. Intervention(s): The sperm samples were prepared for fluorescence in situ hybridization. Main Outcome Measure(s): The disomy frequencies for chromosomes 8, 15, 18, and sex chromosomes were determined using fluorescence in situ hybridization. Result(s): The mean frequencies of disomy for autosomes were 0.18% for chromosome 8, 0.06% for chromosome 15, 0.2% for chromosome 18, and 0.24% for gonosomes (XX, 0.04%; YY, 0.05%; XY, 0.15%). Conclusion(s): This study confirms other previous evaluations on restricted numbers of patients. Our results seem to confirm a relative equiprobability of disomy frequencies concerning the different chromosomal pairs during male meiosis.

Multicolor fluorescence in situ hybridization analysis of aneuploidy and diploidy frequencies in 225,846 sperm from 10 normal men.

Aneuploidy and diploidy frequencies for chromosomes 1, 12, X, and Y were assessed in 225,846 sperm from 10 normal men. Results from 5 of the men have previously been reported. Multicolor fluorescence in situ hybridization (FISH) was used to control for lack of probe hybridization and to distinguish diploidy from disomy. A minimum of 10,000 sperm per donor were evaluated for each chromosome. Sperm were considered disomic if two fluorescent signals were separated by a distance of a minimum of one signal domain. The mean frequencies of disomic sperm for chromosomes 1 and 12 were 0.11% (range 0.05-0.18%) and 0.16% (range 0.10-0.25%), respectively. The means for the sex chromosomal aneuploidies were 0.07% XX, 0.18% YY, and 0.16% XY, totaling 0.42% for all sex chromosomes (range 0.23-0.71%). The incidence of disomic sperm for the sex chromosomes was significantly increased compared to the frequency for the autosomes, corroborating results obtained from studies of sperm karyotypes and spontaneous abortions. The mean frequencies of single X- and Y-bearing sperm were 50.1% and 49.0%, respectively--not significantly different from 50%. The mean frequency of diploid sperm was 0.16% (0.06-0.42%). Interdonor heterogeneity was found to exist for disomy 1, XX, YY, and diploidy, suggesting significant variation among normal men. Comparison of these FISH results to our historical sperm karyotypes demonstrated that the sex ratios and disomy frequencies for chromosomes 1 and X were similar. However, there was a significantly increased frequency of disomic sperm for chromosomes 12, YY, and XY in FISH data compared with sperm karyotypes. In general, FISH data agreed quite well with values from sperm karyotyping, including the increased frequency of sex chromosomal aneuploidy compared with autosomal aneuploidy in sperm. Multicolor FISH analysis permits an accurate distinction between disomic and diploid sperm and allows analysis of large sample sizes. This powerful technology may be useful for future studies of potential environmental and occupational mutagens.

Analysis of chromosomal abnormalities in human sperm after chemotherapy by karyotyping and fluorescence in situ hybridization (FISH)

The frequency of numerical and structural chromosomal abnormalities was studied in the sperm of a lymphoma patient 3 years after MACOP-B chemotherapy (CT). Sperm karyotyping was performed by fusion of human sperm with hamster oocytes and analysis of 193 Q-banded sperm chromosomes. Multicolor fluorescence in situ hybridization (FISH) was performed on 10,228 sperm for analysis of disomy frequencies for chromosomes 1 and 12 and on 10,664 sperm for chromosomes X and Y. Sperm karyotyping demonstrated numerical abnormalities in 7.3% of the spreads, 6.7% hypohaploid and 0.5% hyperhaploid, giving a conservative estimate of aneuploidy of 1%. Structural chromosomal abnormalities were present in 7.3% of the karyotypes and 0.5% had both numerical and structural abnormalities. Results of FISH analyses yielded disomy frequencies of 0.10%, 0.11%, 0.04%, 0.05%, and 0.18% for chromosomes 1, 12, X, Y, and XY, respectively. The frequency of diploid sperm was 0.09%. The frequency of abnormalities was not significantly increased compared to control donors for any of the studies. Also, the frequencies of X- and Y-bearing sperm did not differ significantly from 50% in the sperm karyotyping or FISH studies.