Chromosome studies in 496 infertile males with a sperm count below 10 million/ml.
ABSTRACT Chromosome studies were performed on 106 men with azoospermia and 390 men with oligozoospermia (consistent sperm count below 10 million/ml). Constitutional chromosome abnormalities were found in 14.1% of the azoospermia group and in 5.1% of the oligozoospermia group. An overall incidence of 7.1% constitutional abnormalities indicates that this criterion of selection may be advisable for routine chromosome analysis of infertile men. A reduction of 25% in the workload increases the yield of chromosome abnormalities in the group of infertile men to 10-14 times above that expected in the normal population.
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ABSTRACT: To analyse the relationship between male infertility and chromosomal translocations, and the influence of different types of chromosomal translocations on semen quality, testicular volume and hormone levels. A retrospective cohort of infertile men was recruited for chromosomal analysis using standard Giemsa stain banding. Physical examinations, semen analysis, hormonal analysis and the detection of azoospermia factor (AZF) microdeletions were carried out. Men with normal fertility were used as controls. Among the 1056 infertile men, 22 had chromosomal translocations (2.1%), including seven with Robertsonian translocations (0.7%), 11 with autosome-autosome reciprocal translocations (1.0%) and four with gonosome-autosome reciprocal translocations (0.4%). Left and right testicular volumes of patients with chromosomal translocations were significantly smaller than those in the fertile control group. There were no significant differences in hormone levels between patients with chromosomal translocations and fertile controls, except for significantly lower testosterone levels in patients with Robertsonian and gonosome-autosome reciprocal translocations compared with the controls. All AZF microdeletion analyses showed normal results. Chromosomal translocations may cause reductions in testicular volume and testosterone level, which may impact spermatogenesis, resulting in azoospermia or oligozoospermia and male infertility.The Journal of international medical research 01/2012; 40(6):2274-83. · 0.96 Impact Factor
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ABSTRACT: 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.Journal of Assisted Reproduction and Genetics 03/2012; 29(6):539-46. · 1.82 Impact Factor
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ABSTRACT: Oligozoospermia (low sperm count) is a common semen deficiency. However, to date, few genetic defects have been identified to cause this condition. Moreover, even fewer molecular-genetic diagnostic tests are available for patients with oligozoospermia in the andrology clinic. Based on animal and gene expression studies of oligozoospermia, several molecular pathways may be disrupted in post-meiotic spermatozoa. One of the disrupted pathways is protein ubiquitination and cell apoptosis. A critical protein involved in this pathway is the ubiquitin conjugating enzyme 2B, UBE2B. Absence of Ube2b in male mice causes spermatogenic meiotic disruption with increased apoptosis, leading to infertility. To examine the association between messenger RNA defects in UBE2B and severe oligozoospermia (0.1-10x10(6) cells/ml), sequencing screening of sperm cDNA in 326 oligozoospermic patients and 421 normozoospermic men was performed. mRNA alterations in UBE2B were identified in sperm in 4.6% (15/326) of the oligozoospermic patients, but not found in control men, suggesting strong association between mRNA defects and oligozoospermia (χ(2)=19, p=0.0001). Identified UBE2B alterations include 9 splicing, 4 missense, and 2 nonsense alterations. The following screen of corresponding DNA regions did not reveal causative DNA mutations, suggesting a post-transcriptional nature of identified defects. None of these variants were reported in the dbSNP database, although other splicing abnormalities with low level of expression were present in 11/421 (2.6%) controls. Our findings suggest that two distinct molecular mechanisms, mRNA editing and splicing processing, are disrupted in oligozoospermia. We speculate that the contribution of post-transcriptional mRNA defects to oligozoospermia could be greater than previously anticipated.Molecular Human Reproduction 01/2013; · 4.54 Impact Factor