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I Liebaers

Publications and source records attributed to I Liebaers.

At least 109 records · Page 6Linked to original sources
PubMed1996

Prospective follow-up study of 423 children born after intracytoplasmic sperm injection.

In order to evaluate the safety of the intracytoplasmic sperm injection (ICSI) procedure, a prospective follow-up study of 423 children born after ICSI was carried out. The aim of this study was to compile data on karyotypes, congenital malformations, growth parameters and developmental milestones. Before starting the infertility treatment, couples were asked to participate in a follow-up study including genetic counselling and prenatal diagnosis. The follow-up study of the child was based on a visit to the paediatrician-geneticist at birth or at 2 months of age, at 1 year and at 2 years of age when a physical examination for major and minor malformations and a psychomotoric evaluation were done. Between April 1991 and September 1994, 320 pregnancies obtained after ICSI led to the birth of 423 children (222 singletons, 186 twins and 15 triplets). Prenatal diagnosis determined a total of 293 karyotypes, one of which was abnormal (0.3%), and four were benign familial structural aberrations, all inherited from the paternal side. A total of 14 (3.3%) major malformations were observed, defined as those causing functional impairment or requiring surgical correlation. Neurological or developmental problems at the age of 2 months were found in 14 children, four of whom were multiples. Compared to most registers of children born after assisted reproduction and to registers of malformations in the general population, the figure of 3.3% major malformations is within the expected range. Before drawing any firm conclusion, further careful evaluations of the available data are necessary.

Adult↗
PubMed1996

Constitution of semen samples from XYY and XXY males as analysed by in-situ hybridization.

A brightfield microscopical in-situ hybridization (ISH) technique was applied to semen samples of two 47,XYY males, one 46,XY/47,XXY/XXY male with fertility problems, and two normal 46,XY men, who served as controls. The use of a standardized nuclear DNA decondensation method, together with double-target ISH and morphological staining, allowed an accurate study of the sex chromosomal content and morphology of spermatozoa. In the males carrying an extra sex chromosome, we detected X- and Y-bearing spermatozoa in a ratio which did not differ significantly from the 1:1 ratio found in normal males. Aneuploidy for the sex chromosomes was found in approximately 15% of the spermatozoa of both XYY males and in 3% of the XXY male. The most striking finding was the relatively low percentage of spermatozoa in these patients, with an average of 65% in the XYY males and 84% in the XXY male. The other cells represented immature germ cells (IGC), including spermatogonia and spermatocytes arrested at various stages of spermatogenesis. Apparently, in XYY or XXY men, these IGC are shed into the semen to an increased extent as compared to normal, fertile men. The sex chromosome constitution of these IGC was heterogeneous. However, the finding that the majority of spermatozoa in semen of 47,XYY and 47,XXY males carried a single sex chromosome strengthens the hypothesis that a 46,XY germ cell line must be present, apparently with a proliferative advantage over the 47,XYY or 47,XXY cells.

Adult↗
PubMed1996

Testicular sperm recovery in nine 47,XXY Klinefelter patients.

Klinefelter's syndrome is generally characterized by hypergonadotrophic hypogonadism and azoospermia. The clinical features, however, are variable, and occasionally severe oligozoospermia may be present. Usually in these cases a 46,XY/47,XXY mosaic karyotype is involved. However, focal spermatogenesis and severe oligozoospermia have been reported in 47,XXY individuals too. In the present study we investigated whether testicular spermatozoa can be recovered in 47,XXY patients with a view to intracytoplasmic sperm injection (ICSI). In four out of nine apparently non-mosaic 47,XXY patients, spermatozoa were recovered from the wet preparations of testicular tissue and ICSI was performed in three couples. In one patient in whom spermatozoa were successfully recovered and used for ICSI, no spermatozoa were retrieved at a second trial. Although these results show that in some 47,XXY individuals testicular spermatozoa can be successfully recovered and even used for ICSI, at present this approach should be considered experimental. There may indeed be some concern about the chromosomal normality of the embryos generated through this infertility treatment. Patients with Klinefelter's syndrome should therefore be counselled about the complexity of this treatment, which involves multiple testicular biopsies from hypogonadal testes, ICSI and preimplantation diagnosis by fluorescence-in-situ hybridization.

Adult↗
PubMed1996

Preimplantation diagnosis for X and Y normality in embryos from three Klinefelter patients.

In some 47,XXY Klinefelter patients without evidence of mosaicism, testicular spermatozoa can be successfully recovered and used for intracytoplasmic sperm injection (ICSI). To ensure the replacement of embryos with a normal X and Y chromosome pattern, preimplantation diagnosis can be performed. This paper reports on three 47,XXY Klinefelter patients from whom it was possible to retrieve testicular spermatozoa in order to perform ICSI. From their healthy wives a total of 27 oocyte-cumulus complexes were retrieved from which 22 metaphase-II oocytes were obtained and injected; 19 of these were intact after injection. Two distinct pronuclei were observed in eight oocytes (42.1%) 18 h after injection. On day 3 of development, five embryos (62.5%) had reached at least the 6-cell stage and were of sufficient quality to undergo biopsy and subsequent preimplantation diagnosis for sex chromosome analysis by fluorescent in-situ hybridization. The four embryos diagnosed as normal were transferred to three respective patients, resulting in one biochemical pregnancy. The remaining cells of the fifth embryo were analysed afterwards, revealing a normal X and Y chromosome constitution. So far, in the five embryos diagnosed, a normal sex chromosome pattern has been observed.

Embryo, Mammalian↗
PubMed1996

Localization by fluorescence in situ hybridization of the human functional beta-glucuronidase gene (GUSB) to 7q11.21 --> q11.22 and two pseudogenes to 5p13 and 5q13.

The gene coding for human beta-glucuronidase (GUSB) was mapped to 7q11.21 --> q11.22 by fluorescence in situ hybridization (FISH), thus clarifying the contradictory published localizations of this gene. Multiple unprocessed pseudogenes and pseudogene fragments for GUSB have been described. However, only two weak signals, one at chromosome band 5p13 and the other at 5q13, could be detected with FISH, suggesting considerable divergence between GUSB and its related sequences.

Chromosome Mapping↗
PubMed1996

Molecular analysis of patients with beta-glucuronidase deficiency presenting as hydrops fetalis or as early mucopolysaccharidosis VII.

Although not all mucopolysaccharidosis type VII (MPS VII) neonates present with hydrops fetalis or with related symptoms, hydrops fetalis is a common form of presentation of this mucopolysaccharidosis. We used reverse-transcription-PCR-SSCP and direct sequencing to screen for mutations in the human beta-glucuronidase cDNA of 17 MPS VII patients with severe presentation of the disease. Mutations resulting in an unstable mRNA were detected in genomic DNA with direct sequencing of the PCR-amplified beta-glucuronidase exons. We found extensive genetic heterogeneity in MPS VII alleles: in addition to 6 or 12 previously reported mutations (L176F, R216W, R357X, R382C, W507X, and W627C), we detected 14 undescribed mutations in the beta-glucuronidase coding region that produce MPS VII alleles (G136R, E150K, S312X, Y320S, Y320C, H351Y, R382H, R374C, R435P, R477W, G572D, Y508C, K606N and 1900 delta GA). The mutations in hydropic fetuses were widely scattered in the beta-glucuronidase gene. Analysis of three polymorphic sites of the mutant alleles (1766T/C, 1972C/T and a new 1091+27C/G polymorphism) allowed exclusion of identity by descent for some recurrent mutations. Three of four mutations introducing a premature translation stop codon were found to affect mRNA abundance and/or structure. Expression studies provided evidence for the causal relationship between each of the mutations found in MPS VII alleles and the enzyme deficiency, in that all mutations identified exhibited markedly reduced enzyme activity expressed in COS7 cells following transfection with the mutant cDNA.

Adult↗
PubMed1995

Normal pregnancy after preimplantation DNA diagnosis of a dystrophin gene deletion.

To perform preimplantation DNA diagnosis for Duchenne muscular dystrophy (DMD) in a female carrier of a dystrophin gene deletion of exons 3-18, we developed a polymerase chain reaction (PCR)-based assay of exon 17 sequences. Exon 17 was efficiently amplified in all 50 single blastomeres of normal control embryos and in five blastomeres of one male embryo of the DMD carrier obtained after a first preimplantation diagnosis (PID) for gender determination. In ten blastomeres of another two male embryos of the DMD carrier, no PCR signals were observed, probably as a result of the deletion. After intracytoplasmic sperm injection, embryos were analysed for exon 17 and three of the four embryos showing normal PCR signals were replaced, resulting in a singleton pregnancy. Prenatal diagnosis showed a female karyotype and DNA analysis indicated that the fetus was not a DMD carrier.

Adult↗
PubMed1995

Amplification of exon 11 of the gene for the alpha-chain of beta-N-acetylhexosaminidase in single human blastomeres.

OBJECTIVE: To evaluate the possibility of using polymerase chain reaction (PCR) technology for preimplantation diagnosis for Tay-Sachs disease. DESIGN: Polymerase chain reaction on single human blastomeres. SETTING: Bad quality embryos from IVF analyzed in an academic research genetics lab. INTERVENTIONS: Patients underwent standard IVF procedures as infertility treatment. RESULTS: Amplification was seen in 89.5% of the blastomeres; only one blank was contaminated. CONCLUSION: The technique of PCR on single blastomeres is ready to be used in clinical preimplantation diagnosis for Tay-Sachs disease.

Base Sequence↗
PubMed1995

Obstetric outcome of 424 pregnancies after intracytoplasmic sperm injection.

An evaluation of the outcome of pregnancies resulting from intracytoplasmic sperm injection for severe male factor infertility was conducted by analysing the data obtained from the patients and/or their obstetrician/gynaecologist on standardized questionnaires. The data from 424 pregnancies between April 1991 and September 1994 were analysed. Early pregnancy loss before 16 weeks occurred in 99 cases (23.3%), including 48 clinical abortions (11.3%), 47 subclinical pregnancies (11.1%) and four ectopic pregnancies (0.9%). Vanishing twins and triplets, which could be regarded as early embryonic wastage, were found in 36 cases (8.5%). One pregnancy was interrupted at week 15 of gestation because of anhydramnios, and four pregnancies (0.9%) ended in spontaneous late abortions before 26 weeks. A total of 320 pregnancies (75.5%) resulted in the birth of at least one child; 222 of these (69.3%) were singletons, 93 were twins (29.1%) and five were triplets (1.6%). The problems of prematurity and low birthweight were especially related to the multiplicity of pregnancies. Furthermore, from among the total of 423 babies born, we have observed three cases of stillbirth and five cases of neonatal mortality. The perinatal mortality rate was therefore 18.9 per 1000 births. The results of this study show that the obstetric outcome of these pregnancies was similar to that obtained after conventional in-vitro fertilization and other assisted reproduction techniques.

Abortion, Spontaneous↗
PubMed1995

Comparative follow-up study of 130 children born after intracytoplasmic sperm injection and 130 children born after in-vitro fertilization.

The safety of intracytoplasmic sperm injection (ICSI) as a novel procedure of assisted fertilization may be assessed by the health of the children born. In a prospective follow-up study of children born after assisted procreation, 130 children born consecutively after ICSI were compared with 130 control children born after in-vitro fertilization (IVF). In both groups, mothers were matched for age and had the same standard treatment protocol. There were 74 singleton, 50 twin and six triplet children in each group. Prenatal karyotyping and ultrasound screening, physical examination at birth and developmental milestones, with a follow-up at 2 months and 1 year, were recorded. Prenatal karyotypes were obtained in 100 of the 130 children in the ICSI group compared with 22 of the 130 children in the matched IVF group. All karyotypes were normal except for one prenatally detected mosaicism, which was not confirmed at birth. Four major malformations were detected in the ICSI group (holoprosecencephaly, femur fibula ulna syndrome and palatoschisis in two children), compared with six in the matched IVF group (coarctation of the aorta, palatoschisis, hypospadias, unilateral cryptorchidism, soft tissue syndactily and 11-beta-hydroxylase deficiency). In the ICSI and IVF groups, mean +/- SD birth weights were 2.94 +/- 0.67 and 2.80 +/- 0.73 kg, lengths were 48.46 +/- 3.56) and 47.47 +/- 5.78 cm, and head circumferences were 33.79 +/- 2.20 and 31.19 +/- 8.88 cm respectively. Among the ICSI singletons, the mean +/- SD birth weight was 3.28 +/- 0.58 kg and among the twins it was 2.60 +/- 0.43 kg; for the IVF singletons and matched twins the mean +/- SD birth weights were 3.19 +/- 0.56 and 2.36 +/- 0.61 kg respectively. In conclusion, there was no difference in the paediatric follow-up of 130 children born after ICSI and 130 children born after conventional IVF in age-matched control patients.

Adult↗
PubMed1995

The use of epididymal and testicular spermatozoa for intracytoplasmic sperm injection: the genetic implications for male infertility.

The results and rationale of using testicular and epididymal spermatozoa with intracytoplasmic sperm injection (ICSI) for severe cases of male infertility are reviewed. A total of 72 consecutive microsurgical epididymal sperm aspiration (MESA) cases were performed for congenital absence of the vas (CAV) and for irreparable obstructive azoospermia. ICSI was used to obtain normal embryos for transfer and fertilization in 90% of the cases. The overall fertilization rate was 46% with a normal cleavage rate of 68%. The pregnancy and delivery rates per transfer were 58 and 37% respectively. The delivery rate per cycle was 33%. In many cases, no epididymal spermatozoa were available and so testicular sperm extraction (TESE) was used for sperm retrieval. The transfer rate was lower with TESE (84 versus 96%) and the spermatozoa could not be frozen and saved for use in future cycles. However, there was little difference in pregnancy rates using epidiymal or testicular spermatozoa. The results were not affected by whether the obstruction was caused by CAV or failed vasoepididymostomy. Both fresh and frozen spermatozoa gave similar results; the only significant factor appeared to be the age of the female. Because of the consistently good results obtained using epididymal sperm with ICSI when compared with conventional IVF, and the similarly good results with testicular tissue spermatozoa, ICSI is mandatory for all future MESA patients. All CAV patients and their partners should be offered genetic screening for cystic fibrosis; hence pre-implantation embryo diagnosis should be available in any full service MESA programme. It is now clear that even with non-obstructive azoospermia, e.g. Sertoli-cell only, or maturation arrest, there are usually some small foci of spermatogenesis which allow TESE with ICSI to be carried out. This means that even in men with azoospermia due to absence of spermatogenesis or to a block in meiosis, there are usually a few spermatozoa available in the testes that are adequate for successful ICSI. Finally, it is likely that some forms of severe male factor infertility are genetically transmitted and although ICSI offspring have been shown to be completely normal, it is possible that the sons of these infertile couples will also require ICSI when they grow up and wish to have a family.

Adult↗
PubMed1995

Simultaneous amplification of the two most frequent mutations of infantile Tay-Sachs disease in single blastomeres.

Tay-Sachs disease is a lysosomal storage disease, which in its most severe form leads inexorably to death during infancy. We have developed a method for preimplantation diagnosis, using polymerase chain reaction (PCR) technology, by which the two most frequent mutations occurring in this disease can be amplified simultaneously. We have tested this method on single blastomeres and have compared four lysis methods: (i) boiling in water at 94 degrees C for 15 or (ii) 30 min, and (iii) incubation in an alkaline lysis buffer for 30 min at 94 degrees C or (iv) at 65 degrees C for 10 min. The amplification percentages were 21, 67, 71 and 91% respectively.

Base Sequence↗
PubMed1995

A pseudodeficiency allele (D152N) of the human beta-glucuronidase gene.

We present evidence that a 480G-->A transition in the coding region of the beta-glucuronidase gene, which results in an aspartic-acid-to-asparagine substitution at amino acid position 152 (D152N), produces a pseudodeficiency allele (GUSBp) that leads to greatly reduced levels of beta-glucuronidase activity without apparent deleterious consequences. The 480G-->A mutation was found initially in the pseudodeficient mother of a child with mucopolysaccharidosis VII (MPSVII), but it was not on her disease-causing allele, which carried the L176F mutation. The 480G-->A change was also present in an unrelated individual with another MPSVII allele who had unusually low beta-glucuronidase activity, but whose clinical symptoms were probably unrelated to beta-glucuronidase deficiency. This individual also had an R357X mutation, probably on his second allele. We screened 100 unrelated normal individuals for the 480G-->A mutation with a PCR method and detected one carrier. Reduced beta-glucuronidase activity following transfection of COS cells with the D152N cDNA supported the causal relationship between the D152N allele and pseudodeficiency. The mutation reduced the fraction of expressed enzyme that was secreted. Pulse-chase experiments indicated that the reduced activity in COS cells was due to accelerated intracellular turnover of the D152N enzyme. They also suggested that a potential glycosylation site created by the mutation is utilized in approximately 50% of the enzyme expressed.

Alleles↗