Genetic risk factors in infertile men with severe oligozoospermia and azoospermia.

BACKGROUND: Male infertility due to severe oligozoospermia and azoospermia has been associated with a number of genetic risk factors. METHODS: In this study 150 men from couples requesting ICSI were investigated for genetic abnormalities, such as constitutive chromosome abnormalities, microdeletions of the Y chromosome (AZF region) and mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. RESULTS: Genetic analysis identified 16/150 (10.6%) abnormal karyotypes, 8/150 (5.3%) AZFc deletions and 14/150 (9.3%) CFTR gene mutations. An abnormal karyotype was found both in men with oligozoospermia and azoospermia: 9 men had a sex-chromosomal aneuploidy, 6 translocations were identified and one marker chromosome was found. Y chromosomal microdeletions were mainly associated with male infertility, due to testicular insufficiency. All deletions identified comprised the AZFc region, containing the Deleted in Azoospermia (DAZ) gene. CFTR gene mutations were commonly seen in men with congenital absence of the vas deferens, but also in 16% of men with azoospermia without any apparent abnormality of the vas deferens. CONCLUSIONS: A genetic abnormality was identified in 36/150 (24%) men with extreme oligozoospermia and azoospermia. Application of ICSI in these couples can result in offspring with an enhanced risk of unbalanced chromosome complement, male infertility due to the transmission of a Y-chromosomal microdeletion, and cystic fibrosis if both partners are CFTR gene mutation carriers. Genetic testing and counselling is clearly indicated for these couples before ICSI is considered.     

Chromosomal findings in 150 couples referred for genetic counselling prior to intracytoplasmic sperm injection

A total of 150 infertile couples underwent chromosome analysis and genetic counselling before intracytoplasmic sperm injection (ICSI). Chromosomal abnormalities, including low-level sex chromosome mosaicism, were detected in 12% of the men and an unexpectedly high 6% of the women. Chromosomal abnormalities included gonosomal mosaicism in 13 cases, Robertsonian translocations in four males, autosomal reciprocal translocations in five cases, reciprocal translocation involving a sex chromosome in one case, inversions in three cases and a marker chromosome in one male. Chromosomal variants found in 11 women and 13 men were not included in the above percentages. Couples with a chromosomal aberration in one partner received a second counselling. The different aspects of genetic counselling in these couples are discussed. In conclusion, we recommend genetic counselling and chromosomal analysis of men and women prior to ICSI therapy.      

Histological and genetic analysis and risk assessment for chromosomal aberration after ICSI for patients presenting with CBAVD

Intracytoplasmic sperm injection (ICSI) has opened a new field in the treatment of male infertility, leading to a debate concerning its genetic safety. In this study we present an analysis of 11 patients presenting congenital bilateral absence of the vas deferens (CBAVD). In all 11 cases, genetic counselling, histological analysis of testicular biopsies, cystic fibrosis transmembrane conductance regulator (CFTR) mutation screenings of both partners and spermatozoa three-colour fluorescent in-situ hybridization (FISH) analysis were performed. A total of 31 CFTR mutations were screened and mutations were found in eight out of 11 cases, with DeltaF508 being the most common mutation found. Histological analyses showed that seven out of 11 patients had normal tubule/membrane/interstitium (TMI) and Johnsen scores, while the remaining four patients had mild impairment of testicular parenchyma. The average aneuploidy rate was 6.8 +/- 3.9% compared with two control subjects with 4.4 and 5.4% aneuploidy rates respectively, using FISH analysis. After ICSI, the fertilization and pregnancy rates were 66.2 and 22.7% respectively. Thus, in our case of CBAVD, the risk of chromosomal aberration following ICSI, in the absence of a CFTR mutation in the male patient and/or in his partner, was not higher than in normal fertile men. Furthermore, the pregnancy success rate following ICSI of these CBAVD patients was comparable to the general ICSI population, even when histological analysis showed limited spermatogenesis.     

Genetic analysis of males from intracytoplasmic sperm injection couples

A total of 392 men referred for intracytoplasmic sperm injection (ICSI) participated in genetic analysis. The control group consisted of 100 normal fertile males. Chromosome and DNA analyses were performed to investigate the frequency of Y-chromosome microdeletions and CFTR mutations (the controls underwent DNA analysis only). An abnormal karyotype was found in 4.6% of all males, but the frequency among men with azoospermia was higher, at 11.7%. Y-chromosome microdeletions were found only among men with azoospermia (6.5%) and men with extreme oligospermia (2%). Compound heterozygosity for CFTR mutations was found in men with azoospermia (3.9%) and congenital bilateral absence of vas deferens (CBAVD) only. We conclude that all couples referred for ICSI should be offered chromosome analysis. DNA analysis for Y-chromosome microdeletions should be reserved for men with azoospermia or extreme oligospermia (<1 x 106 spermatozoa). Analysis for CFTR mutations should be limited to those with obstructive azoospermia or those with a family history of cystic fibrosis.     

The complex relationships between cystic fibrosis and congenital bilateral absence of the vas deferens: clinical, electrophysiological and genetic data

Congenital bilateral absence of the vas deferens (CBAVD) is found in 1-2% of infertile males and in most male cystic fibrosis (CF) patients. CF and some of the CBAVD cases were found to share the same genetic background. In this study, 21 males with CBAVD had extensive physical and laboratory testing for symptoms of CF. Possible defective cellular chloride transport was measured by interstitial current measurement of rectal suction biopsies. Cystic fibrosis transmembrane conductance regulator (CFTR) gene mutation analysis was performed for 10 common CFTR mutations. CF-related symptoms were found in six men. On laboratory testing slightly abnormal liver and pancreatic function was found in seven patients. The sweat test was found to be abnormal in four patients; interstitial current measurement showed defective chloride excretion in 11 patients. CFTR gene mutations were found in 66% of the patients: eight were compound heterozygotes; in six, only one common mutation could be detected. The 5T allele in one copy of intron 8 was found in four men. CBAVD appears to be a heterogeneous clinical and genetic condition. A CFTR gene mutation was found in both copies of the allele or interstitial current measurement showed defective chloride excretion in 14/21 cases. Genetic counselling is clearly indicated for couples seeking pregnancy through epididymal or testicular sperm aspiration and intracytoplasmic sperm injection.     

Screening of mutations in the CFTR gene in 1195 couples entering assisted reproduction technique programs

Genetic testing of the cystic fibrosis transmembrane conductance (CFTR) gene is currently performed in couples undergoing assisted reproduction techniques (ART), because of the high prevalence of healthy carriers in the population and the pathogenic relationship with congenital bilateral absence of vas deferens (CBAVD). However, discordant data have been reported concerning the usefulness of this genetic test in couples with no family history of cystic fibrosis (CF). In this study, we report the results of CFTR molecular screening in 1195 couples entering ART. Genetic testing was initially carried out in a single partner of each couple. CFTR mutations were detected in 55 subjects (4.6%), a percentage that overlaps with the one reported in the general population. However, significantly higher frequencies of were found in CBAVD individuals (37.5%) and in males with nonobstructive azoospermia (6.6%). The 5T allele was found in 78 patients (6.5%). This figure was again significantly different in males with nonobstructive-azoospermia (9.9%) and in those with CBAVD (100%). All together, 139 subjects (11.6%) had either a CFTR mutation or the 5T allele. Subsequent molecular analysis of their partners disclosed a CFTR mutation or 5T allele in nine cases (6.5%). However, none of these couples had CFTR alterations in both members, a CFTR mutation being invariably present in one partner and the 5T allele in the other. In order to improve genetic counselling of these couples, the TG-M470V-5T association was analyzed, and a statistically significant relationship between 12TG-V470 and CBAVD was detected.     

Genetics: Intracytoplasmic sperm injection in infertile patients with structural chromosome abnormalities

In the present study we investigated the results of cyto-geneticanalysis in male and female patients included in an intracytoplasmicsperm injection (ICSI) programme for severe male infertilityas well as in conceptuses resulting from these ICSI treatments.In the 261 couples treated, 11 male (4.2%) and three female(1.2%) abnormal karyotypes were found, all consisting of structuralchromosome anomalies. Chromosomal translocation exhibited thehighest frequency (eight males and two females), and there werealso three cases of chromosomal inversion (two males and onefemale) and one male with one additional marker chromosome.There was no difference in fertilization rates among coupleswith abnormal (n = 14) and normal (n = 147) cytogenetic results,and the rates of clinical pregnancy per ICSI attempt were 25.0%(5/20) and 20.6% (78/378) respectively. In pregnancies obtainedin couples with normal karyotypes, all of the 108 fetuses werefree of chromosomal abnormalities. Among the eight fetuses fromcouples with chromosome structural anomalies, three out of fiveand two out of three inherited the cytogenetic defects foundin their father or mother respectively. In this series of 83ICSI pregnancies there were no chromosomal abnormalities otherthan those inherited from the parents. These findings suggestthat normal pregnancy rates can be obtained by ICSI in casesof chromosomal translocation in couples with severe male infertility.However, until further evaluations of available data can beperformed, cytogenetic analysis must be conducted prior to ICSIin men with low sperm counts, and genetic counselling must includeprenatal diagnosis for all growing conceptuses.     

Prevalence of chromosomal abnormalities in 2078 infertile couples referred for assisted reproductive techniques

BACKGROUND: This study analyses the prevalence of karyotype changes and Yq11 microdeletions among couples referred for assisted reproduction techniques. METHODS: Prior to receiving either IVF or ICSI treatment, each partner of 2078 infertile couples was screened for karyotype changes by GTG-banding technique on peripheral lymphocytes. No subject presented with obvious phenotype of chromosomal rearrangement. All the oligo/azoospermic men with normal karyotype were further investigated by PCR for Yq11 microdeletions. RESULTS: Eighty-two out of 2078 couples (3.95%) had one partner carrying a chromosomal change, and 10 out of 202 (4.95%) men showed Yq11 microdeletions. The chromosomal rearrangements were 44 (2.1%) translocations, 23 (1.1%) gonosomal mosaics, six (0.3%) 47,XXY, five (0.24%) marker chromosomes, three (0.14%) inversions and one (0.05%) duplication. Frequency of anomalies in men and women were similar: 42 and 40 cases respectively. CONCLUSIONS: Partners of infertile couples requiring IVF or ICSI treatment appear to be affected by higher frequency of chromosomal rearrangements than the general population. Categories with greater risk were represented by men with sperm cell count <20 x 10(6) sperm/ml, and women with history of pregnancy loss.     

Two novel missense and one novel nonsense CFTR mutations in Iranian males with congenital bilateral absence of the vas deferens

Congenital bilateral absence of the vas deferens (CBAVD) is a frequent cause of obstructive azoospermia. Nearly 75% of men with CBAVD have at least one detectable common cystic fibrosis (CF) transmembrane conductance regulator (CFTR) mutation. To study the involvement of CFTR mutations in the Iranian population with presumed low CF frequency, we analysed 112 Iranian CBAVD males. Three Iranian CBAVD males with no clinical CF phenotype indicated by a normal karyotype, normal pancreatic function and sweat chloride concentration and no Y chromosome microdeletions were studied for CFTR mutations, IVS8-5T mutations and M470V exon 10 missense polymorphism. The entire coding sequence of each gene was analysed using a combination of the denaturing gradient-gel electrophoresis or by single-strand conformation analysis and direct DNA sequencing. Also, 52 fertile males were tested as controls to rule out polymorphism. This approach allowed us to detect one novel nonsense mutation (K536X) in the nucleotide-binding domain 1 (NBD1) region and two novel missense mutations (Y122H and T338A) in the M2 and M6 regions of CFTR gene in our studied population, which were not reported previously. Also, the conservation of changed nucleotide and amino acid in mutated regions was analysed by aligning with nine different species. K536X nonsense mutation (transversion) was found in the first NBD (NBF1), which plays an important regulatory role in CFTR function. It was, therefore, considered as a severe allele responsible for elevated sweat chloride levels and obstructive azoospermia. Because Y122H and T338A mutations were compound heterozygote with the IVS8-5T, it is difficult to judge the severity of these mutations and their role in the CBAVD phenotype.     

Molecular analysis of the IVS8-T splice variant 5T and M470V exon 10 missense polymorphism in Iranian males with congenital bilateral absence of the vas deferens

Congenital bilateral absence of the vas deferens (CBAVD) is responsible for 2-6% of male infertility in which mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene have been identified. To investigate CBAVD at the molecular level in Iran, we have characterized the mutations in the CFTR gene in 106 patients with this condition. None had clinical manifestations of cystic fibrosis (CF). We also analysed a DNA variant (the 5T allele) in a noncoding region of CFTR, which causes reduced levels of the normal CFTR protein and M470V exon 10 missense polymorphism. Five of the 106 patients with CBAVD had mutations in both copies of the CFTR gene, and none of them had the 5T allele. Eighty-five patients had a mutation in at least one copy of CFTR, and of these patients, 46 had one 5T allele (in 11 cases, two alleles and in 35 cases, just one allele of 5T was detected). In 21 patients, no CFTR and 5T mutations were found (19.81%). 5T/M470 genotype was found in 19 patients, 5T/V470 was found in 3 and 5T with heterozygote form of M470V was found in 24 CBAVD patients. In CBAVD patients, 28 F508del carriers were identified. Most of our patients with CBAVD have mutations in the CFTR gene. The combination of the 5T allele in one copy of the CFTR gene with a CF mutation in the other copy is the most common cause of CBAVD in Iran. The 5T allele mutation has a wide range of clinical presentations and revealed a high frequency, occurring in patients with CBAVD or moderate forms of CF and infertile men.     

Type and frequency of chromosome aberrations in 781 couples undergoing intracytoplasmic sperm injection.

Cytogenetic investigations were performed in 781 couples prior to intracytoplasmic sperm injection (ICSI) because of severe male infertility or fertilization failures in previous in-vitro fertilization attempts. Out of these 1562 patients, 1012 had a normal karyotype without any aberrations (64.8%), 204 patients had an abnormal karyotypes (13.1%). These chromosome aberrations included constitutional aberrations (4.4%), fragile sites of autosomes (3.0%), low level mosaicism of sex chromosomes (4.0%) and secondary structural chromosome aberrations (4.2%). Combinations of different types of abnormalities were stated. Another 346 patients (22.1%) showed single cell aberrations; the significance of these is unclear at the moment. Constitutional chromosome aberrations were detected in 69 patients. The following chromosome aberrations were observed: 35 sex chromosomal aberrations (comprising hyperploidies of X or Y chromosomes, mosaicisms and derivative X and Y chromosomes), 34 autosomal aberrations including 14 reciprocal translocations, five Robertsonian translocations, six inversions, one marker chromosome, one trisomy 18 mosaicism and seven other structural aberrations. Three autosomal regions showed fragile sites: 6q13 in 2.9% of the patients, 17p12 and 10q24 in 0.05% each. In conclusion, our data show that a high number of infertile couples in an ICSI programme are affected by chromosome aberrations which occur in both sexes. It is suggested that a chromosomal analysis should be performed on both partners before ICSI treatment is initiated.     

Analysis by mass spectrometry of 100 cystic fibrosis gene mutations in 92 patients with congenital bilateral absence of the vas deferens

BACKGROUND: Limited mutation analysis for congenital bilateral absence of the vas deferens (CBAVD) has revealed only a minority of men in whom two distinct mutations were detected. We aimed to determine whether a more extensive mutation analysis would be of benefit in genetic counselling and prenatal diagnosis. METHODS: We studied a cohort of 92 men with CBAVD using mass spectrometry and primer oligonucleotide base extension to analyse an approximately hierarchical set of the most common 100 CF mutations. RESULTS: Analysis of 100 CF mutations identified 33/92 (35.9%) patients with two mutations and 29/92 (31.5%) with one mutation, compound heterozygosity accounting for 94% (31/33) of those with two mutations. This panel detected 12.0% more CBAVD men with at least one mutation and identified a second mutation in >50% of those considered to be heterozygotes under the two routine 25 mutation panel analyses. CONCLUSION: Compound heterozygosity of severe/mild mutations accounted for the vast majority of the CBAVD patients with two mutations, and underscores the value of a more extensive CF mutation panel for men with CBAVD. The CF100 panel enables higher carrier detection rates especially for men with CBAVD, their partners, partners of known CF carriers, and those with 'mild' CF with rarer mutations.     

Cystic fibrosis mutation screening in CBAVD patients and men with obstructive azoospermia or severe oligozoospermia

Congenital bilateral absence of the vas deferens (CBAVD) found in otherwise healthy infertile males, is associated with a high incidence of mutated cystic fibrosis transmembrane conductance regulator (CFTR) alleles, and is considered a genital form of cystic fibrosis (CF). The CF gene may also be involved in the aetiology of male infertility in cases other than CBAVD. The present study was undertaken to test the involvement of CFTR gene mutations in 14 CBAVD males and additionally in cases of male infertility caused by obstructive azoospermia (n = 10) and severe oligozoospermia (n = 3). The entire coding region of the CFTR gene was analysed using denaturing gradient gel electrophoresis (DGGE). The three allele (5T, 7T, 9T) polymorphic tract of thymidines in intron 8 (IVS8-polyT) of which the 5T allele acts as a mild mutation, causing reduced levels of normal CFTR mRNA due to deletion of exon 9, was also analysed. Of the 14 CBAVD cases, four (28.6%) were found to have mutations in both copies of the CFTR gene, six (42.8%) had one CFTR mutation, and in the remaining four (28.6%) no CFTR mutations were found. Of the 10 cases with obstructive azoospermia, three (30%) had one CFTR mutation and in the remaining seven (70%) no mutations were found. None of the three severe oligozoospermia cases carried a CFTR mutation. The frequency of the IVS8(5T) allele was 14.3% (4/28) for the CBAVD cases and 5% (1/20) for the obstructive azoospermia cases, none of the severe oligozoospermia males carried the IVS8-5(5T) allele. The data indicate that while there is a strong association between male infertility caused by CBAVD and mutations in the CFTR gene, cases of obstructive azoospermia without CBAVD also seem to be associated with CFTR gene mutations.      

Improved detection of cystic fibrosis mutations in infertility patients with DNA sequence analysis

BACKGROUND: Accurate determination of mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene is critical for genetic counselling and treatment of obstructive azoospermia. Of concern is that detection rates with routine CFTR mutation panels vary widely depending on patient ancestry; and such panels have limited value for azoospermic patients, who are more likely to carry rare mutations. An alternative approach offers comprehensive, CFTR mutation analysis by a DNA sequence method. We investigated whether this method could improve CFTR detection rates in men with obstructive azoospermia in a prospective study of men with obstructive azoospermia and their partners who were referred for genetic counselling and testing at one of two institutions. METHODS: Sixteen patients with congenital absence of the vas deferens (CAVD, n = 14) or idiopathic obstructive azoospermia (n = 2) were studied. DNA from all patients was analysed for mutations by the DNA sequence method. In addition to this method, six men underwent CFTR analysis by a common 25 or 31 mutation panel coupled with poly T analysis. In 10 subjects, common mutation panel findings were inferred from DNA sequence method results. RESULTS: Overall, 12/16 (75%) azoospermic patients had one or more CFTR mutations and/or 5T alleles, including 12 mutations in 10 patients (two compound heterozygotes) and seven 5T alleles in six patients (one homozygote). The sequence method detected all mutations and three variants of unknown significance. By comparison, the common mutation panels detected only 3/12 mutations (25%) and 0/3 variants. CONCLUSION: The DNA sequence method detects more CFTR mutations than common mutation panels. Given the serious, clinical consequences of transmitting such mutations, this study underscores the importance of accurate, CFTR mutation detection in men with obstructive azoospermia and their partners.     

A novel missense mutation D513G in exon 10 of the cystic fibrosis transmembrane conductance regulator (CFTR) gene identified in a French CBAVD patient. Mutations in brief no. 175. Online

Congenital bilateal absence of the vas deferens (CBAVD) with obstructive azoospermia is a congenital reproductive disorder that affects one in 10000 male individuals. The observation that many men presenting with CBAVD have mutations in their CFTR genes had led to the proposal that CBAVD may be a primary genital form of cystic fibrosis. We report here one novel mutation located in exon 10 of the CFTR gene. This mutation, named D513G (A-->G at position 1670), has been found in one of 83 patients with CBAVD from France, the analysis of exon 10 using a chemical clamp DGGE assay allowed us to identify three CF mutations AEF508 (37/166; 22%), AE1507 (1/166; 0/6%) and D513G (1/166; 0.6%), and two variants M470V and E528E (1716 G>A). The novel D513G mutation has not been found in more than 200 non-CF chromosomes and in a sample of 300 CF chromosomes from French classical CF patients.     

Impaired spermatogenesis in men with congenital absence of the vas deferens

It is generally assumed that men with congenital bilateral absence of the vas deferens (CBAVD) have azoospermia because of obstruction and that sperm production is normal. This study examines spermatogenesis in men with CBAVD to assess the validity of this assumption. We identified all men with CBAVD who had undergone either a diagnostic or therapeutic fertility procedure. Procedures included diagnostic biopsy, testis fine needle aspiration (FNA) mapping, microscopic epididymal sperm aspiration (MESA), and testis sperm extraction (TESE). Among 33 CBAVD men, 18 underwent testis biopsy, 27 had MESA/TESE, and 10 had FNA mapping. On evaluation of these procedures, normal spermatogenesis was present in 29 men. Four men (12%) demonstrated impaired spermatogenesis. One patient had FNA testis cytology consistent with late maturation arrest, another demonstrated hypospermatogenesis on biopsy and low sperm yield by MESA, and two patients had pure Sertoli cell only histology on biopsy. Aetiologies for impaired spermatogenesis included varicocele and underlying genetic abnormalities. Although patients with CBAVD are assumed to have normal spermatogenesis and infertility due simply to obstruction, the potential for concomitant defects in sperm production exists. A clinical suspicion of testis failure should prompt further diagnostic evaluation of spermatogenesis prior to sperm retrieval. In addition, genetic counselling should be offered and testing for genetic lesions, including cystic fibrosis gene mutations and/or variants, Y chromosome microdeletions, and karyotype abnormalities, should be considered.     

Congenital bilateral absence of the vas deferens, cystic fibrosis mutation analysis and intracytoplasmic sperm injection

The aim of this study was to assess the outcome of intracytoplasmic sperm injection (ICSI) with fresh and frozen-thawed surgically retrieved spermatozoa from men diagnosed with congenital bilateral absence of the vas deferens (CBAVD). Twenty-seven azoospermic men with their partners were treated [25 with CBAVD and two with clinical cystic fibrosis (CF)]. CF gene mutation analysis and genetic counselling was provided. Spermatozoa were aspirated by microsurgical epididymal sperm aspiration (MESA), percutaneous epididymal sperm aspiration (PESA) or open testis biopsy. Of the men with CBAVD, 60% carried a single mutation, 20% were compound heterozygotes, and 20% had no CF mutation identified. Of the 28 sperm aspiration procedures, 86% had supplementary spermatozoa for cryopreservation with 83% of those samples assessed as satisfactory when thawed. Of 29 cycles with fresh spermatozoa a fertilization rate of 76% of oocytes injected and 17% embryo implantation rate occurred. Twenty-four cycles in which cryopreserved spermatozoa were used resulted in an oocyte fertilization rate of 69% and embryo implantation rate of 20%. Eighteen clinical pregnancies occurred with 14 live births without congenital anomaly. Two pregnancies were achieved following pre-implantation genetic diagnosis. It is concluded that the presence of CF mutations in the male partner does not compromise in-vitro fertilization treatment outcomes or the opportunity for healthy live births.     

Cystic fibrosis phenotype evaluation and paternity outcome in 50 males with congenital bilateral absence of vas deferens

BACKGROUND: Most infertile males with congenital bilateral absence of vas deferens (CBAVD) carry mutations on the cystic fibrosis transmembrane conductance regulator gene and may express mild cystic fibrosis (CF) symptoms. Barriers to paternity for these men can now be overcome by assisted reproduction. Our aims were to investigate the CF-related phenotype and clinical outcome for 50 patients with CBAVD seen at a CF adult centre between 1992 and 1999. METHODS AND RESULTS: The investigation of the patients included screening for 22 CF mutations and identification of the poly-T variant of intron 8, sweat testing, clinical investigation for CF-related extra-genital manifestations, and genetic counselling. CFTR mutations were detected on 56 alleles of the 50 patients. A total of 15 (30%) was compound heterozygote and 26 (52%) heterozygote. In all, 38% of the patients had a positive sweat test. Four patients were diagnosed with typical CF not detected previously. Twenty-one patients became fathers following ICSI (eight cases), artificial insemination by donor or IVF with sperm donor (seven cases) or through adoption (six cases). A mail survey allowed the identification of CF-related clinical symptoms. Information on the occurrence of CF-related symptoms was obtained for 58.5% of patients: in the absence of initial symptoms, no new clinical signs were reported. CONCLUSION: Patients diagnosed with CBAVD need genetic counselling before assisted reproduction. Even when no wish for paternity is expressed, CF gene screening should be associated with at least a sweat test and clinical evaluation because of possible mild forms of CF disease. Medical follow-up did not reveal any new symptoms.     

北京地区8609例不良孕产史夫妇的染色体核型分析

目的探讨不良孕产史夫妇与染色体核型异常的关系。方法采集不良孕产史夫妇病历资料,并抽取外周血培养,然后进行常规G显带核型分析。结果 8609例不良孕产史夫妇中,共检出异常染色体核型521例,异常率为6.05%。其中随体变异174例,异常率为2.02%,染色体倒位164例,异常率为1.90%;副缢痕的增长15例,异常率为0.17%,平衡易位131例,异常率为1.52%,数目异常37例,异常率为0.43%。核型异常发生率在不同性别中差异无显著性。结论染色体核型异常是导致不良孕产史的重要原因之一,对不良孕产史夫妇双方进行细胞遗传学检查,提供优生咨询,再孕指导与监测,能够有效防止患儿出生,提高出生人口素质。     

Safety issues in assisted reproduction technology: should ICSI patients have genetic testing before treatment? A practical proposition to help patient information

ICSI is a highly efficient treatment of male factor infertility and therefore increasingly used to treat infertile men successfully. However, when used to treat patients with a genetic cause for their infertility, there may be an increased risk for the offspring. Chromosome aberrations, Y chromosome microdeletions and CFTR (cystic fibrosis transmembrane conductance regulator) mutations alone may explain up to 25% of azoospermia and severe oligozoospermia. These genetic defects could be identified before treatment, in which case informed decisions could be made by the couple to be treated concerning the treatment, prenatal testing or preimplantation genetic diagnosis. Therefore, we propose that men with very low sperm counts (<5 x 10(6)/ml) considering ICSI should always be informed of the possibility of genetic testing. The information should include a precise statement of the implications of the results for the patient, his family and his offspring, and reassurance that a decision to test or not to test, or the subsequent test results will not be used as a reason for withholding treatment. Testing should always remain voluntary, and the couples themselves should decide whether or not they choose to be tested. If an abnormality is identified, patients should be referred to specialist genetic counselling.