1 Centre for Medical Genetics and 2 Centre for Reproductive Medicine, University Hospital, Dutch-speaking Brussels Free University (Vrije Universiteit Brussel), Laarbeeklaan 101, 1090 Brussels, Belgium
3 To whom correspondence should be addressed. Email: katrien.stouffs{at}az.vub.ac.be
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Abstract |
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Key words: infertility treatment/male infertility/microdeletions/Y chromosome
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Introduction |
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The role of the Y chromosome in male infertility was suggested for the first time in 1976, when on the karyotype of six infertile patients a deletion of a large part of the long arm of the Y chromosome was found (Tiepolo and Zuffardi). Since the 1990s, many studies have reported on the prevalence of Yq microdeletions. By performing a systematic analysis of >80 publications describing the prevalence of Yq microdeletions, we found an overall prevalence of 7.6%. These Yq microdeletions are found more often in patients with non-obstructive azoospermia (10%) compared with patients with severe oligozoospermia (
6%). Vogt et al. (1996)
described the presence of Yq microdeletions in three azoospermia factor regions, referred to as AZFa, AZFb and AZFc. The majority of deletions affect the AZFc region (
65% of the deletions). Kuroda-Kawaguchi et al. (2001)
reported that recombination between direct repeats (amplicons b2 and b4) causes the deletion of the complete AZFc region. This deleted region contains at least three protein-coding gene families: DAZ, BPY2 and CDY1. The absence of the complete AZFa region is observed less frequently (
7% of the deletions) than that of the AZFc region. The majority of deletions of the AZFa region are caused by recombination between two proviruses spaced by
800 kb (Blanco et al., 2000
; Kamp et al., 2000
; Sun et al., 2000
) and lead to the deletion of DBY and USP9Y. The absence of the AZFb region is observed in
16% of the deletions, while the deletion of AZFb + AZFc is observed in
7% of the deletions. The presence of palindromes is the underlying cause of AZFb deletions and AZFb + AZFc deletions: AZFb is deleted by recombination between palindrome P5 and the proximal arm of palindrome P1, while AZFb + AZFc is deleted by recombination between palindrome P5 and the distal arm of palindrome P1 or by recombination between palindrome P4 and the distal arm of palindrome P1 (Repping et al., 2002
). The AZFb region contains 10 potential protein-encoding genes: RBMY, SMCY, PRY, CDY2, XKRY, EIF1AY, Cyorf15A, Cyorf15B, HSFY and RPS4Y2 (Skaletsky et al., 2003
). The mechanism behind AZFa + AZFb deletions has not yet been clarified, and this kind of deletion is rarely observed (<2% of the deletions). The mechanism behind deletions of the three AZF regions, which are found in
3% of the reported deletions, remains unknown.
The phenotypes resulting from the different deletions are variable. About half the patients with an AZFc deletion have spermatozoa in their ejaculates, while the likelihood of finding sperm in patients with a deletion of the AZFa or AZFb region or in whom more than one AZF region is absent is very limited (Brandell et al., 1998; Page et al., 1999
; Krausz et al., 2000
; Kamp et al., 2001
; Hopps et al., 2003
). On the other hand, the phenotype of patients with partial deletions of the AZFb region is very heterogeneous, and for about half of the patients sperm can be found (Brandell et al., 1998
; Page et al., 1999
; Hopps et al., 2003
; Krausz et al., 2003
).
The development of ICSI (Palermo et al., 1992; Van Steirteghem et al., 1993
; Devroey and Van Steirteghem, 2004
) has allowed patients with severe oligozoospermia to have children. Even a proportion of non-obstructive azoospermic patients in whom some spermatozoa could be retrieved by testicular sperm extraction (TESE) are now able to have children (Vernaeve et al., 2003a
, 2004
).
Some, though not all, men with Yq microdeletions are thus able to reproduce. However, since the Y chromosome is vertically transmitted from father to son, the deletion and therefore also the fertility problem will be passed on. Nowadays, preimplantation genetic diagnosis (PGD) gives these couples the possibility to select female embryos for transfer (Staessen et al., 2003).
This study reports on the outcome of the infertility treatment in 38 couples where the male partner has a Yq microdeletion. The possibility of retrieving sperm from the ejaculate or from testicular biopsies, and the histopathology of the testicular biopsies were compared with the type of Yq deletion. The possibility of using PGD to select female embryos was discussed with some of the couples. In couples in whom sperm was available, the outcome of ICSI was assessed. A number of the couples where ICSI was impossible or unsuccessful opted for donor sperm.
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Materials and methods |
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Isolation of DNA and sequence-tagged site (STS) analysis for Yq deletions
To search for Yq microdeletions, DNA was isolated from peripheral blood using the QIAamp Blood Maxi Kit Protocol from Qiagen. Until 1999, patients with idiopathic male infertility were screened for Yq microdeletions by using three STSs located in the three AZF regions: sY84, sY132 and sY254. Since 1999, an extra STS (sY158) is used, which is located in the distal region of AZFc. For the 28 patients for whom one or more of these STSs failed to amplify, the extent of the Yq deletion was determined further by analysing the DNA of the patients with a set of 27 primer pairs, spread over five multiplex PCR sets. Mixes were as follow: mix I (sY84, sY134, sY117, sY102, sY151, sY94 and sY88), mix II (sY143, sY157, sY81, sY182 and sY147), mix III (sY86, sY105, sY82, Y6PHc54pr, sY153 and sY97), mix IV (sY14, sY95, sY127, sY109 and sY149) and mix V (Y6BaH34pr, Fr-15-IIpr, Y6HP52pr and Y6D14pr). The PCRs and thermocycling conditions are described in Van Landuyt et al. (2000). The extent of one deletion of the AZFa region has been determined by using extra STSs in this region: sY87, GY6, DBY1, DBY2, sY596 and sY615. This deletion has also been confirmed by mapping the breakpoints in the HERV15 proviruses flanking the AZFa region with STSs sY1180, sY1181 and sY1064 in the proximal provirus, and sY1065, sY1183, sY1185 and sY1186 in the distal provirus.
Sperm analysis and retrieval
Sperm concentration and motility were determined, as recommended by the World Health Organization (1999); sperm morphology was assessed using the strict Kruger criteria (Kruger et al., 1988
). For patients in whom semen parameters had been determined several times, a mean value was calculated. Patients were classified as azoospermic (no spermatozoa in the ejaculate after several centrifugation steps on at least two samples), cryptozoospermic (<0.1x106 spermatozoa/ml) or severely oligozoospermic (0.15x106 spermatozoa/ml). All azoospermic patients had a non-obstructive azoospermia. The procedure of TESE has been described by Vernaeve et al. (2003a)
. Under general anaesthesia, a testicular biopsy was taken, which was immediately analysed for the presence of spermatozoa. When spermatozoa or elongated spermatids were found in this sample, the surgery was terminated. If no spermatozoa or elongated spermatids were detected, at least four samples were taken randomly from each side. When in these samples no sperm cells were detected, the tissue was digested with collagenase IV (Crabbé et al., 1998
). TESE was performed on the same day of oocyte retrieval (fresh TESE) or spermatozoa retrieved by TESE were frozen and thawed on the day of ICSI (frozen TESE) (Verheyen et al., 2004
).
Testicular biopsy and histopathology
During the TESE procedure, testicular biopsies were also taken for histological examination, performed in the pathology department (Tournaye et al., 1997). A pathology report of a testicular biopsy was available for most of the patients, as well as information on the presence or absence of spermatozoa at the examination of the testicular tissues taken prior to ICSI. The final description reported in this study is based on the most advanced stage of spermatogenesis observed in the histological sample, combined with the absence or presence of spermatozoa in testicular tissue or in the ejaculate. When, for instance, histopathology showed a maturation arrest and spermatozoa were found by TESE, the final description is incomplete maturation arrest. When no spermatozoa were found after TESE, the diagnosis is complete maturation arrest.
Ovarian stimulation, ICSI and PGD procedures
Controlled ovarian stimulation of the female patients was carried out by a combination of GnRH analogues and urinary HMG, or recombinant FSH. When at least four ovarian follicles had reached a size of 18 mm, ovulation was induced by administration of 10 000 IU of HCG. Ultrasound-guided oocyte retrieval was carried out 36 h after the HCG injection (Platteau et al., 2002). In the laboratory, follicular fluid was examined for the presence of cumulusoocyte complexes. In vitro culture conditions, removal of surrounding cumulus and corona cells, search for spermatozoa and microinjection of single sperm into the cytoplasm of metaphase II (MII) oocytes have been described in detail (Joris et al., 2003
). Daily assessment of fertilization and embryo development was carried out until the time of embryo transfer (ET, day 3 or day 5 after retrieval).
For patients who opted for PGD in order to transfer only female and/or euploid embryos, embryo biopsy was carried out on day 3, after which fluorescence in situ hybridization (FISH) was performed. Euploid embryos and/or female embryos which further developed normally were transferred on day 5 (Platteau et al., 2004). At first, only PGD for sexing was available. For this procedure, FISH was performed using three direct labelled probes for chromosomes X, Y and 18 (Staessen et al., 1999
). Today, PGD for aneuploidy screening (PGDAS) is performed and a selection of euploid XX embryos can also be performed. For this procedure, FISH was performed in two rounds, as described previously (Staessen et al., 2003
, 2004
), by which chromosomes X, Y, 13, 18 and 21 are detected in round 1, and chromosomes 16 and 22 in round 2.
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Results |
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In eight patients with a Yq microdeletion, another possible cause of male infertility was found. Five patients had a varicocele: three of these had a deletion of the complete AZFc region, one had a deletion of the distal region of AZFc, and one had a deletion of AZFb. One patient with a deletion of AZFb + AZFc had a history of cryptorchidism. One patient with an AZFc deletion had had an infection of the testis. The contribution of these factors to male infertility is unclear. One also had ejaculatory problems besides an AZFc deletion.
Recovery of spermatozoa in ejaculate or testicular tissue
The presence or absence of spermatozoa in the ejaculate according to the type of microdeletion is summarized in Table II. Most of the patients who had some spermatozoa in their ejaculate were patients with an AZFc deletion (n=11). One patient with an AZFb deletion had very few spermatozoa in his ejaculate in a first semen sample (20 spermatozoa/ml), while in a second semen sample no spermatozoa were found. Both measurements were performed in our laboratory, with 3 months in between. None of the patients with an AZFa, AZFb + AZFc or AZFa + AZFb + AZFc deletion had spermatozoa in their ejaculates. Overall, 31.6% of the patients with Yq microdeletions were cryptozoospermic or severely oligozoospermic; the remaining 68.4% were azoospermic.
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Sperm could be retrieved for 20 out of the 38 patients, either in the ejaculate (n=12) or in testicular tissue (n=8), and so ICSI was offered to these couples (Tables I and IV, Figure 1). However, four of these men could not go through with ICSI or declined to do so. The reasons for this were as follows: the first patient with an AZFb deletion (no. 26) was initially cryptozoospermic, but was subsequently azoospermic, even in a testis biopsy (Table I). For a second patient (Table I: no 21), a few spermatozoa were found in a first testicular biopsy, but did not survive cryopreservation, and no spermatozoa were found in a second biopsy. The wife of the third patient (no. 8) became pregnant spontaneously, but paternity testing was not performed (Table I). The fourth patient (no. 4) opted for sperm donations but, after several attempts, no live birth was obtained (Table I).
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Fourteen of the 38 couples to whom ICSI was proposed were counselled concerning PGD with sex selection and/or with aneuploidy screening. Eight opted for the transfer of XX embryos, and one couple (Table I: no. 13) opted for aneuploidy screening without performing sexing. Another five couples refused sex selection to avoid the birth of a probably infertile male child.
Of the eight couples who were in favour of sex selection, four had at least one ICSI cycle. The first couple (Table I: no. 1) had two cycles in which PGD was performed for sexing as well as for aneuploidy screening. No embryos were transferred because of the absence of normal euploid embryos or embryos of sufficient quality for transfer. The second couple (Table I: no. 7) had PGD in the second cycle only, after a girl had already been born. PGD of the only available embryo revealed that it was of male sex. However, this couple asked to transfer this embryo. An ongoing pregnancy, measured by the presence of an FHB was obtained. The third couple (Table I: no. 19) had PGD in the first cycle, in which three female embryos were transferred, but no pregnancy was obtained. Hoping to increase the chance of a pregnancy by avoiding embryo biopsy, this couple refused PGD in the next two cycles, but in neither of these cycles was a pregnancy obtained. The fourth couple (Table I: no. 20) underwent PGD in two cycles. In the first cycle, no normal developing female embryos were obtained, but four male embryos and two abnormal embryos were. As a consequence, no transfer was performed. In the second cycle, two female, three male and two abnormal embryos were obtained. Two female embryos were thus transferred, but again no pregnancy occurred. Another couple (Table I: no. 21), for whom the ICSI procedure was not performed due to the lack of sperm cells, had planned to perform PGD only if more than four embryos were obtained.
Donor sperm
Of the 18 patients for whom no spermatozoa at all were obtained, six patients had chosen donor sperm insemination to fulfil the patients' wish for a child (Table VII). Seven of the 18 couples had started treatment with a view to ICSI, and the partners of the Yq-deleted men had thus been stimulated. For two of these couples (Table VII, nos 28 and 38), a back-up with donor sperm was foreseen. Both women became pregnant by using ICSI with donor sperm, but one miscarried (Table VII, no. 28). These two patients started again with donor sperm and now have a baby. Of the remaining azoospermic couples, four patients had also chosen to perform intra-uterine insemination with donor sperm. All four patients became pregnant and delivered a baby. Thus, six of these 18 couples could fulfil their child wish as a result of using donor sperm. As previously described, another two patients (Table VII, nos 4 and 16) for whom sperm was found also opted for donor sperm. Seven out of the eight couples for whom donor sperm was used delivered at least one baby (88%).
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Discussion |
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For 33 of the 38 male patients, karyotype analysis has been performed. Unfortunately, for five patients, a karyotype was not available. These included three patients with an AZFc deletion, one with an AZFb + AZFc deletion and one with an AZFa + AZFb + AZFc deletion. For these patients, it is thus unknown whether an additional chromosomal abnormality might have worsened the fertility problems.
The presence of spermatozoa is a prerequisite to be able to help these couples with ICSI. In 20 of the 38 patients, sperm could be obtained from the ejaculate (n=12 or 32%) or from the testis (n=8 or 21%). Of these patients, 19 had an AZFc deletion. This leaves us with only one sperm-producing patient with a deletion outside AZFc, namely in AZFb. In fact, this patient had a few spermatozoa in a first sample, but none were found 3 months later. Even in testicular biopsies, no sperm cells were found. It is unclear what must be concluded from these data. Since azoospermia is defined as no spermatozoa in the ejaculate, after several centrifugation steps on at least two samples, we have classified this patient as cryptozoospermic. It is possible, although highly unlikely, that for this patient spermatogenesis is still ongoing in a few tubuli. As the TESE procedure is limited by the number of biopsies taken, it may not be representative for the whole testis. On the other hand, a maturation arrest at the level of spermatogonia is generally not associated with hidden islands of normal spermatogenesis.
In this study, sperm is thus most likely to be found in patients with an AZFc deletion, but not all men with an AZFc deletion produce sperm. In the literature, data similar to those reported here are described for the AZFc region: spermatozoa can be found in the ejaculate of about half of the patients with an AZFc deletion (Hopps et al., 2003). The chance of finding spermatozoa for patients with a complete AZFa or AZFb deletion or with a deletion of more than one AZF region is very limited (Brandell et al., 1998
; Page et al., 1999
; Krausz et al., 2000
; Kamp et al., 2001
; Hopps et al., 2003
).
Also for the histopathology, data comparable with those published before were found. Deletions of the AZFa region and of more than one AZF region are associated with Sertoli cell-only syndrome (Kamp et al., 2001). The phenotypic appearances of testicular tissues of men with AZFb deletions depend on the extent of the deletion. Patients with a deletion of the complete AZFb region mostly show a maturation arrest in their testicular tissue, while the phenotype of patients with partial AZFb deletions is unpredictable (Krausz et al., 2003
; Simoni et al., 2004
). The group of men with AZFc deletions in this study is, as also has been described in the literature, very heterogeneous.
From the literature and the present results of sperm retrieval and histopathology, one might argue that the chance of finding spermatozoa in patients with a deletion of the complete AZFa or AZFb region is virtually nil. Therefore, to these patients, it should be mentioned that so far no spermatozoa have been found in patients with a complete AZFa or AZFb deletion.
So far, a successful ICSI treatment has only been possible for patients with an AZFc deletion, in our centre as well as in the literature. For the 16 patients who had at least one ICSI treatment, on average, 2.5 ICSI cycles were performed per couple (40 cycles/16 couples) and the overall fertilization rate in these 40 cycles was 55% (209 out of 379). When comparing the fertilization rate in the group of patients for whom ejaculated spermatozoa (13 cycles) or testicular sperm cells (27 cycles) were used, the fertilization rate was significantly higher (P<0.0001, 2 test) in the group with ejaculated spermatozoa (69%) compared with the group with testicular sperm (47%). These data are similar to those reported in the literature (van Golde et al., 2001
; Oates et al., 2002
; Choi et al., 2004
).
In this study, the overall clinical pregnancy rate per ET and per cycle was 21.9% (seven out of 32) and 17.5% (seven out of 40), respectively. Our data are in the same range as the data described by van Golde et al. (2001), who found a pregnancy rate per ET and per cycle of 18% (three out of 17) and 16% (three out of 19), respectively. On the other hand, these rates are lower than those described by Choi et al. (2004)
and Oates et al. (2002)
: in the first study, a clinical pregnancy rate of 43% per ET (nine out of 21) and 33% per cycle (nine out of 27) was found, and in the second study a pregnancy rate of 27% per cycle (13 out of 48) was described.
When comparing the pregnancy rates, the number of transferred embryos should be taken into account as well as the women's age, which is an important parameter in determining the success rate. In our study, on average 2.2 embryos were transferred per cycle. In the study of Choi et al. (2004), on average 2.8 embryos were transferred, while in the study of Oates et al. (2002)
, it is not mentioned how many embryos were replaced. However, taking into account the high twin pregnancy rate reported, it can be assumed that more embryos were transferred than in the present study. The average age of the female partners in the studies of van Golde et al. (2001)
and Choi et al. (2004)
is in the same range as our population.
Generally, similar or higher pregnancy rates are reported in the group with ejaculated sperm compared with a group where TESE was used. Oates et al. (2002) have found that the pregnancy rate per cycle was higher for patients for whom ejaculated sperm was used to perform ICSI (47%) compared with patients for whom testicular sperm was used (14%). Choi et al. (2004)
had observed comparable data for both groups: the pregnancy rate per cycle was 33% for both groups and the pregnancy rate per ET was 57 and 36%, respectively, when ejaculated or testicular spermatozoa were used. In the present study, however, the pregnancy rate per ET was 8.3 and 30% in the ejaculate and the TESE group, respectively. When calculated per cycle, these rates were 7.7 and 22%. No explanation can be given for the low pregnancy rate when ejaculated sperm was used. Nevertheless, these differences were not significant, probably because more data are needed.
For our centre, Vernaeve et al. (2003b) have described the outcome of ICSI when fresh testicular sperm was used. For patients with non-obstructive azoospermia, a clinical pregnancy rate per cycle or per ET of 15.4 and 17.9%, respectively, was found. Verheyen et al. (2004)
described a clinical pregnancy rate per cycle or per ET of 20.8 and 25.0%, respectively, when frozen sperm was used. From these data, it may be concluded that, when testicular sperm is used, the outcome observed in the present study is comparable with the general outcome in our centre when testicular sperm is used.
Men with a deletion of the long arm of the Y chromosome will transmit the deletion and thus the fertility problems to all their sons. Therefore, couples in whom the male partner has a deletion on the long arm of the Y chromosome should be informed about the risks of transmitting the deletion. Although several studies have already been published in which ICSI has been performed successfully and boys have been born, no data about genetic counselling for PGD were provided (Page et al., 1999).
The present study is the first to report on the attitude of couples concerning the sex selection or the possible transmission of their fertility problems to their children. One might argue that infertility is not considered as a life-threatening disease and that ICSI might also help their male children if they are infertile (Mansour, 2004). On the other hand, remaining childless might have a serious impact on the relationship of the couple and also on the woman's self-esteem. Moreover, because of the limited sperm retrieval rate, ICSI can be offered to only about half of the patients with an AZF deletion (Hopps et al., 2003
). Also in the present study, spermatozoa were found in about half (20 out of 38 or 52%) of the patients with a deletion in Yq11. Sperm concentrations may vary a great deal, especially when the AZFc region is deleted and, thus, the consequences for the next generation are unpredictable. Furthermore, so far, only a small number of children are born after ICSI where their father has a deletion on the long arm of the Y chromosome and mostly these children are still too young for information about sperm parameters to be collected (Katagiri et al., 2004
). The only studies in which an adult father and son were available for analysis were of cases in which the deletion was transmitted naturally from father to son (Vogt et al., 1996
; Pryor et al., 1997
; Chang et al., 1999
; Saut et al., 2000
; Rolf et al., 2002
; Kühnert et al., 2004). In these studies, the sons were infertile and therefore present at the fertility centre. However, in the studies by Rolf et al. (2002)
and Pryor et al. (1997)
, the reported deletions are small and therefore might represent polymorphisms, while in the studies by Kühnert et al. (2004), Saut et al. (2000)
and Vogt et al. (1996)
, sperm concentrations in the ejaculate of the father were not determined, but these fathers were probably severely oligozoospermic. One may conclude that the phenotype deteriorates in the next generation, but a different genetic background or environmental factors might also be important (Krausz et al., 2003
).
So far, 14 of the 38 couples were counselled about the consequences of transmitting the defective Y chromosome, and PGD was proposed to select female embryos. It should be mentioned that in the first years of Yq microdeletion screening, patients were not informed about the possibility of performing PGD. Moreover, because of language difficulties and socio-cultural aspects, it was not always possible to discuss sex selection fully with the couples. Of the 14 counselled couples, half were in favour of the selection of female embryos, while half the couples were not. However, for three couples that opted for the selection, having a child became in fact the most important factor. One couple wanted to perform PGD only if more than four embryos were obtained. A second couple had one ICSIPGD cycle, but in the next two cycles preferred not to proceed with PGD in order to increase the chance of a pregnancy by avoiding embryo biopsy. For a third couple, only a single male embryo was obtained, which the couple wanted to transfer.
At first, couples were offered PGD for sexing only. However, in the meantime, research has revealed that more chromosome aneuploidies can be found in embryos when using testicular sperm from patients with non-obstructive azoospermia to perform ICSI, so that PGDAS is now also offered (Zenzes and Capser, 1992; Kahraman et al., 2004
; Platteau et al., 2004
). Two couples opted for this technique. For one of these, PGD-AS was performed in combination with sexing.
It has been suggested that patients with a deletion on the long arm of the Y chromosome have a potential risk of having children with Turner syndrome (Siffroi et al., 2000; Patsalis et al., 2002
). Presumably, the presence of Yq microdeletions might cause mitotic instability of the abnormal chromosome. Two couples had PGDAS (analysis of chromosomes 13, 16, 18, 21, 22, X and Y) and another three couples had PGD only for sexing (analysis of chromosomes 18, X and Y). From these five couples, a total of 39 embryos were available for diagnosis. A total of 23 embryos were normal 46,XX (10 embryos) or 46,XY (13 embryos). The remaining embryos had other abnormalities such as no nuclear material, uninterpretable results or abnormal karyotypes other than 45,X0.
In the present study, we also determined for how, many of the couples for whom no spermatozoa were found, insemination with donor sperm might be an option for fulfilling their child wish. No sperm cells were found in 18 patients, and another four patients could not continue with or refused ICSI. Seven of these 22 patients opted for donor sperm. One more couple decided to use donor sperm after several unsuccessful ICSI attempts. All but one of these eight couples were able to conceive, and a total of nine babies were born in 13 cycles. One woman had had several attempts already before going to the hospital, where four more cycles were performed. Three clinical pregnancies were obtained but, unfortunately, no baby was born. As a female factor is probably also involved, embryo donation was suggested.
In conclusion, patients with Yq microdeletions encompassing the complete AZFa and/or AZFb are unlikely to father children in our study as well as in most other studies. For patients with an AZFc deletion, sperm was found in 70%, and when sperm is found the patient's chance of becoming pregnant is 17.5% (seven out of 40). The total chance for patients with AZFc deletions of becoming pregnant is therefore 12% (70%x17.5%). Because of the limited data, it is impossible today to calculate the chance of becoming pregnant if ICSI is combined with PGD. Aneuploidy screening might increase the pregnancy rate by preventing the transfer of aneuploid embryos. On the other hand, the pregnancy rate might decrease because of the biopsy procedure.
During genetic counselling, all couples should be informed carefully about the possibility of performing PGD for the selection of embryos and about the consequent reduction of the number of embryos for transfer. Furthermore, patients should be informed about the possibility of using AID. The chance of becoming pregnant after AID is much higher than after ICSI.
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Acknowledgements |
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References |
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![]() ![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Brandell RA, Mielnik A, Liotta D, Ye Z, Veeck LL, Palermo GD and Schlegel PN (1998) AZFb deletions predict the absence of spermatozoa with testicular sperm extraction: preliminary report of a prognostic genetic test. Hum Reprod 13, 28122815.
Chang PL, Sauer MV and Brown S (1999) Y chromosome microdeletion in a father and his four sons. Hum Reprod 14, 26892694.
Choi JM, Chung P and Veeck L (2004) AZF microdeletions of the Y chromosome and in vitro fertilization outcome. Fertil Steril 81, 337341.[CrossRef][ISI][Medline]
Crabbé E, Verheyen G, Silber S, Tournaye H, Van de Velde H, Goossens A and Van Steirteghem A (1998) Enzymatic digestion of testicular tissue may rescue the intracytoplasmic sperm injection cycle in some patients with non-obstructive azoospermia. Hum Reprod 13, 27912796.
de Kretser DM and Baker HWG (1999) Infertility in men: recent advances and continuing controversies. J Clin Endocrinol Metab 84, 34433450.
Devroey P and Van Steirteghem AC (2004) A review of ten years experience of ICSI. Hum Reprod Update 10, 1928.
Greenhall E and Vessey M (1990) The prevalence of subfertility: a review of the current confusion and a report of two new studies. Fertil Steril 54, 978983.[ISI][Medline]
Hopps CV, Mielnik A, Goldstein M, Palermo GD, Rosenwaks Z and Schlegel PN (2003) Detection of sperm in men with Y chromosome microdeletions of the AZFa, AZFb and AZFc regions. Hum Reprod 18, 16601665.
Iammarrone E, Balet R, Lower AM, Gillott C and Grudzinskas JG (2003) Male infertility. Best Pract Res Clin Obstet Gynaecol 17, 211229.[CrossRef][ISI][Medline]
Joris H, De Vos A, Janssens R, Devroey P, Liebaers I and Van Steirteghem A (2003) Comparison of the results of human embryo biopsy and outcome of PGD after zona drilling using acid Tyrode medium or a laser. Hum Reprod 18, 18961902.
Kahraman S, Benkhalifa M, Donmez E, Biricik A, Sertyel S, Findikli N and Berkil H (2004) The results of aneuploidy screening in 276 couples undergoing assisted reproductive techniques. Prenat Diagn 24, 307311.[CrossRef][ISI][Medline]
Kamp C, Huellen K, Fernandes S, Sousa M, Schlegel PN, Mielnik A, Kleiman S, Yavetz H, Krause W, Kupker W et al. (2001) High deletion frequency of the complete AZFa sequence in men with Sertoli-cell-only syndrome. Mol Hum Reprod 10, 987994.[CrossRef]
Kamp C, Hirschmann P, Voss H, Huellen K and Vogt PH (2000) Two long homologous retroviral sequence blocks in proximal Yq11 cause AZFa microdeletions as a result of intrachromosomal recombination events. Hum Mol Genet 9, 25632572.
Katagiri Y, Neri QV, Takeuchi T, Schlegel PN, Megid WA, Kent-First M, Rosenwaks Z and Palermo GD (2004) Y chromosome assessment and its implications for the development of ICSI children. Reprod Biomed Online 8, 307318.[ISI][Medline]
Krausz C, Quintana-Murci L and McElreavey K (2000) Prognostic value of Y deletion analysis: what is the clinical prognostic value of Y chromosome microdeletion analysis? Hum Reprod 15, 14311434.
Krausz C, Forti G and McElreavey K (2003) The Y chromosome and male fertility and infertility. Int J Androl 26, 7075.[CrossRef][ISI][Medline]
Kruger T, Acosta A, Simmons K et al. (1988) Predictive value of abnormal sperm morphology in in vitro fertilization. Fertil Steril 49, 112117.[ISI][Medline]
Kuroda-Kawaguchi T, Skaletsky H, Brown LG, Minx PJ, Cordum HS, Waterston RH, Wilson RK, Silber S, Oates R, Rozen S et al. (2001) The AZFc region of the Y chromosome features massive palindromes and uniform recurrent deletions in infertile men. Nat Genet 29, 279286.[CrossRef][ISI][Medline]
Mansour R (2004) Preimplantation genetic diagnosis for Y-linked diseases: why not? Reprod Biomed Online 8, 144145.[ISI][Medline]
Oates RD, Silber S, Brown LG and Page DC (2002) Clinical characterization of 42 oligozoospermic men with microdeletion of the AZFc region of the Y chromosome, and of 18 children conceived via ICSI. Hum Reprod 17, 28132824.
Page DC, Silber S and Brown LG (1999) Men with infertility caused by AZFc deletion can produce sons by intracytoplasmic sperm injection, but are likely to transmit the deletion and infertility. Hum Reprod 14, 17221726.
Palermo G, Joris H, Devroey P and Van Steirteghem AC (1992) Pregnancies after intracytoplasmic injection of a single spermatozoon into an oocyte. Lancet 340, 1718.[CrossRef][ISI][Medline]
Patsalis PC, Sismani C, Quintana-Murci L, Taleb-Bekkouche F, Krausz C and McElreavey K (2002) Effects of transmission of Y chromosome AZFc deletions. Lancet 360, 12221224.[CrossRef][ISI][Medline]
Platteau P, Sermon K, Seneca S et al. (2002) Preimplantation diagnosis for fragile Xa syndrome: difficult but not impossible. Hum Reprod 17, 28072812.
Platteau P, Sermon K, Seneca S, Van Steirteghem A, Devroey P and Liebaers I (2004) Comparison of the aneuploidy frequency in embryos derived from testicular sperm extraction in obstructive and non-obstructive azoospermic men. Hum Reprod 19, 15701574.
Pryor JL, Kent-First M, Muallem A, Van Bergen AH, Nolten WE, Meisner L and Roberts KP (1997) Microdeletions in the Y chromosome of infertile men. N Engl J Med 336, 534539.
Repping S, Skaletsky H, Lange J, Silber S, Van Der Veen F, Oates RD, Page DC and Rozen S (2002) Recombination between paindromes P5 and P1 on the human Y chromosome causes massive deletions and spermatogenic failure. Am J Hum Genet 71, 906922.[CrossRef][ISI][Medline]
Rolf C, Gromoll J, Simoni M and Nieschlag E (2002) Natural transmission of a partial AZFb deletion of the Y chromosome over three generations: case report. Hum Reprod 17, 22672271.
Saut N, Terriou P, Navarro A, Levy N and Mitchell MJ (2000) The human Y chromosome genes BPY2, CDY1 and DAZ are not essential for sustained fertility. Mol Hum Reprod 6, 789793.
Siffroi JP, Le Bourhis C, Krausz C, Barbaux S, Quintana-Murci L, Kanafani S, Rouba H, Bujan L, Bourrouillou G, Seifer I et al. (2000) Sex chromosome mosaicism in males carrying Y chromosome long arm deletions. Hum Reprod 15, 25592562.
Simoni M, Bakker E and Krausz C (2004) EAA/EMQN best practice guidelines for molecular diagnosis of Y-chromosomal microdeletions. State of the art 2004. Int J Androl 27, 240249.[CrossRef][ISI][Medline]
Skaletsky H, Kuroda-Kawaguchi T, Minx PJ, Cordum HS, Hillier L, Brown LG, Repping S, Pyntikova T, Ali J, Bieri T et al. (2003) The male specific region of the human Y chromosome is a mosaic of discrete sequence classes. Nature 423, 825837.[CrossRef][ISI][Medline]
Staessen C, Van Assche E, Joris H, Bonduelle M, Vandervorst M, Liebaers I and Van Steirteghem A (1999) Clinical experience of sex determining by fluorescent in-situ hybridization for preimplantation genetic diagnosis. Mol Hum Reprod 5, 328389.
Staessen C, Tournaye H, Van Assche E, Michiels A, Van Landuyt L, Devroey P, Liebaers I and Van Steirteghem A (2003) PGD in 47, XXY Klinefelter's syndrome patients. Hum Reprod Update 9, 319330.
Staessen C, Platteau P, Van Assche E, Michiels A, Tournaye H, Camus M, Devroey P, Liebaers I and Van Steirteghem A (2004) Comparison of blastocyst transfer with or without preimplantation genetic diagnosis for aneuploidy screening in couples with advanced maternal age: a prospective randomised controlled trial. Hum Reprod 19, 28492858.
Sun C, Skaletsky H, Rozen S, Gromoll J, Nieschlag E, Oates R and Page DC (2000) Deletion of azoospermia factor a (AZFa) region of human Y chromosome caused by recombination between HERV15 proviruses. Hum Mol Genet 9, 22912296.
Tiepolo L and Zuffardi O (1976) Localization of factors controlling spermatogenesis in the nonfluorescent portion of the Y chromosome. Hum Genet 34, 119224.[CrossRef][ISI][Medline]
Tournaye H, Verheyen G, Nagy P, Ubaldi F, Goossens A, Silber S, Van Steirteghem AC and Devroey P (1997) Are there any predictive factors for successful testicular sperm recovery in azoospermic patients? Hum Reprod 12, 8086.[CrossRef][ISI][Medline]
van Golde RJ, Wetzels AM, de Graaf R, Tuerlings JH, Braat DD and Kremer JA (2001) Decreased fertilization rate and embryo quality after ICSI in oligozoospermic men with microdeletions in the azoospermia factor c region of the Y chromosome. Hum Reprod 16, 289292.
Van Landuyt L, Lissens W, Stouffs K, Tournaye H, Liebaers I and Van Steirteghem A (2000) Validation of a simple Yq deletion screening programme in an ICSI candidate population. Mol Hum Reprod 6, 291297.
Van Steirteghem AC, Nagy Z, Joris H, Liu J, Staessen C, Smitz J, Wisanto A and Devroey P (1993) Higher fertilization and implantation rates after intracytoplasmic sperm injection. Hum Reprod 8, 10611066.[Abstract]
Verheyen G, Vernaeve V, Van Landuyt L, Tournaye H, Devroey P and Van Steirteghem A (2004) Should diagnostic testicular sperm retrieval followed by cryopreservation for later ICSI be the procedure of choice for all patients with non-obstructive azoospermia? Hum Reprod 19, 28222830.
Vernaeve V, Bonduelle M, Tournaye H, Camus M, Van Steirteghem A and Devroey P (2003a) Pregnancy outcome and neonatal data of children born after ICSI using testicular sperm in obstructive and non-obstructive azoospermia. Hum Reprod 18, 20932097.
Vernaeve V, Tournaye H, Osmanagaoglu K, Verheyen G, Van Steirteghem A and Devroey P (2003b) Intracytoplasmic sperm injection with testicular spermatozoa is less successful in men with nonobstructive azoospermia than in men with obstructive azoospermia. Fertil Steril 79, 529533.[CrossRef][ISI][Medline]
Vernaeve V, Krikilion A, Verheyen G, Van Steirteghem A, Devroey P and Tournaye H (2004) Outcome of testicular sperm recovery and ICSI in patients with non-obstructive azoospermia with a history of orchidopexy. Hum Reprod 19, 23072317.
Vogt PH, Edelmann A, Kirsch S, Henegariu O, Hirschmann P, Kiesewetter F, Kohn FM, Schill WB, Farah S, Ramos C et al. (1996) Human Y chromosome azoospermia factors (AZF) mapped to different subregions in Yq11. Hum Mol Genet 5, 933943.
World Health Organization (1999) WHO Laboratory Manual for the Examination of Human Semen and SemenCervical Interaction, 4th edn. Cambridge University Press, Cambridge.
Zenzes MT and Casper RF (1992) Cytogenetics of human oocytes, zygotes, and embryos after in vitro fertilization. Hum Genet 88, 367375.[ISI][Medline]
Submitted on October 7, 2004; resubmitted on January 13, 2005; accepted on January 17, 2005.
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