1/29. trisomy/tetrasomy 21 mosaicism in CVS: interpretation of cytogenetic discrepancies between placental and fetal chromosome complements.trisomy/tetrasomy 21 mosaicism was found in chorionic villi (semidirect preparation) obtained from a 40 year old pregnant woman. Since both cell lines were abnormal, the couple elected for pregnancy termination. placenta and fetal tissue samples were obtained for cytogenetic study. Long term cultured villi showed a non-mosaic trisomy 21 karyotype, while other tissues showed either a normal karyotype or normal/trisomy21 mosaicism. These discrepancies could be explained by a modified "bottle neck" embryogenic model with a trisomic zygote and a non-disjunction event taking place in one of the first divisions. Our case emphasises the need for confirmatory studies in other tissues when mosaicism is encountered in chorionic villi, even if all cell lines are abnormal.- - - - - - - - - - ranking = 1keywords = embryo (Clic here for more details about this article) |
2/29. Patient with a 22q11.2 deletion with no overlap of the minimal digeorge syndrome critical region (MDGCR).The apparent lack of genotype/phenotype correlation in patients with the DiGeorge anomaly and velocardiofacial syndrome (DGA/VCFS; the "22q11 deletion syndrome") indicates a complex genetic condition. Most cases, whatever the phenotype, have a 1.5-3 Mb chromosomal deletion that includes the minimal DiGeorge critical region (MDGCR). Another potential critical region on 22q11 has been suggested based on two patients with distal deletions outside the MDGCR. We report on a patient with a VCFS phenotype who has a deletion, mapped by short tandem repeat polymorphic loci and fluorescence in situ hybridization analysis, distal to and not overlapping the MDGCR. This patient is deleted for several genes, including the T-box 1 gene (TBX1; a transcription regulator expressed early in embryogenesis) and catechol-O-methyltransferase (COMT; involved in neurotransmitter metabolism). We discuss the role these two genes may play in the clinical phenotype of the patient.- - - - - - - - - - ranking = 1keywords = embryo (Clic here for more details about this article) |
3/29. Sperm quality may adversely affect the chromosome constitution of embryos that result from intracytoplasmic sperm injection.OBJECTIVE: To determine whether the high rate of chromosomal abnormalities in the embryos of an infertile couple were caused by a paternal factor that may have involved the sperm centriole. DESIGN: Case report. SETTING: Private IVF program. PATIENT(S): An infertile couple who underwent IVF-ET because of severe male factor infertility and endometriosis. INTERVENTION(S): Preimplantation genetic diagnosis of chromosomal abnormalities in embryos derived from two cycles of ICSI in which the husband's sperm was used and one in which donor sperm was used. MAIN OUTCOME MEASURE(S): Preimplantation genetic diagnosis with fluorescence in situ hybridization using probes for chromosomes X, Y, 13, 16, 18, and 21, and determination of hCG levels. RESULT(S): Most of the embryos derived from the cycles in which the husband's sperm was used were chromosomally abnormal (82%), whereas all the embryos derived from the cycle in which donor sperm was used were chromosomally normal. The cycle in which donor sperm was used resulted in an ongoing pregnancy. CONCLUSION(S): Paternal factors, which most likely derive from the centrosome, can contribute to numerical chromosomal abnormalities, which in turn may predispose to implantation failure.- - - - - - - - - - ranking = 8keywords = embryo (Clic here for more details about this article) |
4/29. Outcome of preimplantation genetic diagnosis of translocations.OBJECTIVE: To review 35 cases of preimplantation genetic diagnosis (PGD) of translocations with several methods, including telomeric probes. DESIGN: Retrospective study. SETTING: Clinical IVF laboratory. PATIENT(s): Thirty-five couples with one partner carrying a chromosomal translocation. INTERVENTION(s): PGD of translocation after polar-body or embryo biopsy. MAIN OUTCOME MEASURE(s): pregnancy outcome. RESULT(s): Several trends were observed. First, PGD can achieve a statistically significant reduction in spontaneous abortion, from 95% to 13%. Second, the chances of achieving pregnancy are correlated with 50% or more of the embryos being chromosomally normal. Third, patients with robertsonian translocations produced fewer abnormal gametes and more pregnancies than did patients with reciprocal translocations. Fourth, a new fluorescence in situ hybridization protocol for PGD of translocations, which involves applying telomeric probes, has proved adequately reliable with a 6% average error rate. CONCLUSION(s): PGD of translocations achieves a statistically significant reduction in spontaneous abortion, both for polar-body and blastomere biopsy cases. pregnancy outcome depended on the number of normal embryos available for transfer, with patients having <50% abnormal embryos achieving the most pregnancies. Because robertsonian translocations caused fewer abnormal embryos than reciprocal translocations, they also resulted in higher rates of implantation.- - - - - - - - - - ranking = 233.5259898547keywords = preimplantation, embryo (Clic here for more details about this article) |
5/29. Meiotic segregation analysis by FISH investigation of spermatozoa of a 46,Y,der(X),t(X;Y)(qter-->p22::q11-->qter) carrier.Chromosome analysis performed on a 30-year-old man revealed a 46,Y,der(X),t(X;Y)(qter-->p22::q11-->qter) karyotype, confirmed by fluorescence in situ hybridization (FISH). The man was of short stature, and no mental retardation was noticed; genitalia and testes were normal, as were the patient's FSH, LH, and testosterone blood levels. Sperm analysis showed azoospermia at the time of the first sampling and severe oligozoospermia, with 125,000 spermatozoa/milliliter, at the time of the second sampling. The sperm gonosomal complement of this patient and of a 46,XY donor were analyzed using multicolor FISH with X- and Y-chromosome probes. Our results clearly indicated that germinal cells carrying the translocation are able to complete the meiotic process by producing spermatozoa compatible with normal embryonic development, with more than 80% of the spermatozoa having either a y chromosome or a der(X); however, a high level of spermatozoa with gonosomal disomies was observed. We also found a significant increase in the frequency of autosomal disomies in the carrier, which would suggest an interchromosomal effect. All previously reported cases in adult males were associated with azoospermia; testicular histological studies, performed in patients carrying the same X;Y translocation, showed spermatogenetic arrest after pachytene. To our knowledge, this is the first molecular analysis of the gonosomal complement in spermatozoa of men with a t(X;Y)(qter-->p22::q11-->qter).- - - - - - - - - - ranking = 1keywords = embryo (Clic here for more details about this article) |
6/29. Preimplantation genetic diagnosis of pericentric inversions.Inversions are structural chromosome abnormalities that may be associated with infertility, multiple miscarriage and chromosomally unbalanced offspring. Preimplantation genetic diagnosis (PGD) with subtelomeric probes was used to select for transfer only those embryos that were normal or balanced for three pericentric inversions. In contrast to previous protocols the present procedure allows the detection of unbalanced embryos that might arise from U-recombination in the inverted region. Additionally, aneuploidy screening was carried out in two cases by a second round of fluorescent in situ hybridization (FISH) with centromeric probes. Of the three couples that underwent the procedure one became pregnant twice. The first pregnancy delivered a healthy and chromosomally normal baby and the second pregnancy is ongoing with triplets.- - - - - - - - - - ranking = 2keywords = embryo (Clic here for more details about this article) |
7/29. Tricho-rhino-phalangeal syndrome type II (Langer-Giedion) with persistent cloaca and prune belly sequence in a girl with 8q interstitial deletion.A patient with the diagnosis of langer-giedion syndrome (tricho-rhino-phalangeal syndrome type II) and interstitial 8q deletion was also noted to have persistent cloaca and prune belly sequence. This is the first report of this association. If it postulated that these latter embryonic defects may be due to the chromosome abnormality, supporting the definition of contiguous gene syndrome.- - - - - - - - - - ranking = 1keywords = embryo (Clic here for more details about this article) |
8/29. Chromosome 10p deletion in a patient with hypoparathyroidism, severe mental retardation, autism and basal ganglia calcifications.Chromosome 10p terminal deletions have been associated with a DiGeorge like phenotype. haploinsufficiency of the region 10p14-pter, results in hypoparathyroidism, sensorineural deafness, renal anomaly, that is the triad that features the HDR syndrome. Van Esch (2000) identified in a HDR patient, within a 200 kb critical region, the GATA3 gene, a transcription factor involved in the embryonic development of the parathyroids, auditory system and kidneys. We describe a new male patient, 33-year-old, with 10p partial deletion affected by hypocalcemia, basal ganglia calcifications and a severe autistic syndrome associated with mental retardation. Neurologically he presented severe impairment of language, hypotonia, clumsiness and a postural dystonic attitude. A peripheral involvement of auditory pathways was documented by auditory evoked potentials alterations. CT scan documented basal ganglia calcifications. Hyperintensity of the lentiform nuclei was evident at the MRI examination. Renal ultrasound scan was normal. haploinsufficiency for GATA3 gene was documented with FISH analysis using cosmid clone 1.2. Phenotypic spectrum observed in del (10p) is more severe than the classical DGS spectrum. GATA3 has been found to regulate the development of serotoninergic neurons. A serotoninergic dysfunction may be linked with autism in this patient.- - - - - - - - - - ranking = 1keywords = embryo (Clic here for more details about this article) |
9/29. Establishment of a rhabdoid tumor cell line with a specific chromosomal abnormality, 46,XY,t(11;22)(p15.5;q11.23).The malignant rhabdoid tumor is a rare, poorly understood tumor which occurs primarily in children. The kidney is a frequent primary site of origin, but the tumor has arisen in other mesodermally derived tissues as well. Controversy exists regarding the embryonic origin of the rhabdoid tumor and recent histopathologic studies suggest that it may be of neuroepithelial origin. Our immunohistochemical and electron micrographic studies support this theory. No consistent chromosome abnormalities have been reported in this tumor and no cell lines are available for study. We have established and characterized the first rhabdoid tumor cell line. It possesses a specific chromosomal abnormality, 46,XY,t(11;22)(p15.5;q11.23). The translocation may provide an important clue to the pathogenesis of the tumor as well as an opportunity for further study of the involved chromosome regions.- - - - - - - - - - ranking = 1keywords = embryo (Clic here for more details about this article) |
10/29. Mosaic partial trisomy 17q2.Examination of an infant born after prenatal diagnosis of mosaic partial trisomy 17q2 showed the unique phenotypic features of this chromosomal abnormality, that is, frontal bossing, large mouth, brachyrhizomelia, and hexadactyly. amniocentesis was performed because of polyhydramnios and ultrasound diagnosis of fetal craniofacial dysmorphology and rhizomelic shortening of the limbs. Chromosomal mosaicism was restricted to fetal tissue and amniotic fluid cells. The placental chromosomal complement was normal, suggesting that the abnormality developed after differentiation of embryonic and trophoblastic cells. This emphasises the usefulness of cytogenetic evaluation of placental, fetal, and amniotic fluid cells in delineating the pathogenesis of congenital abnormalities.- - - - - - - - - - ranking = 1keywords = embryo (Clic here for more details about this article) |
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