1/45. Mosaic trisomy 17 in amniocytes: phenotypic outcome, tissue distribution, and uniparental disomy studies.mosaicism for trisomy 17 in amniocyte cultures is a rare finding, whilst postnatal cases are exceptional. In order to gain insight into the possible effects of the distribution of the trisomic line and of uniparental disomy (UPD) on embryofoetal development, we have performed follow-up clinical, cytogenetic and molecular investigations into three newly detected prenatal cases of trisomy 17 mosaicism identified in cultured amniotic fluid. In the first case, the pregnancy ended normally with the birth of a healthy girl, and analysis of newborn lymphocytes and of multiple extra-embryonic tissues was indicative of confined placental mosaicism. The second case was also associated with a normal pregnancy outcome and postnatal development, and only euploid cells were found in peripheral blood after birth. However, maternal isodisomy 17 consequent to a meiosis II error and loss of a chromosome 17 homologue was detected in peripheral lymphocytes postnatally. In the third case, pathological examination after termination of pregnancy showed growth retardation and minor dysmorphisms, and the trisomic line was detected in foetal skin fibroblasts. In addition, biparental derivation of chromosome 17 was demonstrated in the euploid lineage. These results, together with previously reported data, indicate that true amniotic trisomy 17 mosaicism is more commonly of extra-embryonic origin and associated with normal foetal development. Phenotypic consequences may arise when the trisomic line is present in foetal tissues. Case 2 also represents the first observation of maternal UPD involving chromosome 17; the absence of phenotypic anomalies in the child suggests that chromosome 17 is not likely to be subject to imprinting in maternal gametes.- - - - - - - - - - ranking = 1keywords = embryo (Clic here for more details about this article) |
2/45. Maternal uniparental isodisomy for chromosome 14 detected prenatally.Maternal uniparental disomy (UPD) for chromosome 14 (upd(14)mat) has been associated with a distinct phenotype. We describe the first case of maternal uniparental isodisomy for chromosome 14 detected prenatally, in a pregnancy with mosaicism for trisomy 14 observed in both a chorionic villus sample (CVS) and in amniocytes. Detailed analysis of polymorphic microsatellites showed that the fetus was essentially isodisomic for one of the mother's chromosomes 14 and that recombination had introduced a mid-long arm region of heterodisomy. The fetus, which died in utero at 18 weeks, showed no apparent pathological features. The case demonstrates for the first time a maternal meiosis II non-disjunction of chromosome 14 leading to a trisomic conception which has been incompletely corrected by 'rescue' in the early embryo.- - - - - - - - - - ranking = 0.33333333333333keywords = embryo (Clic here for more details about this article) |
3/45. A pregnancy following PGD for X-linked dominant [correction of X-linked autosomal dominant] incontinentia pigmenti (Bloch-Sulzberger syndrome): case report.incontinentia pigmenti (Bloch-Sulzberger syndrome) is a rare multisystem, ectodermal disorder associated with dermatological, dental and ocular features, and in <10% of cases, severe neurological deficit. pedigree review suggests X-linked dominance with lethality in affected males. Presentation in female carriers is variable. Following genetic counselling, a mildly affected female carrier diagnosed in infancy with a de novo mutation was referred for preimplantation sexing, unusually selecting for male gender, with an acceptance of either normality or early miscarriage in an affected male. Following standard in-vitro fertilization and embryo biopsy, fluorescence in situ hybridization (FISH) unambiguously identified two male and two female embryos. A single 8-cell, grade 4 male embryo was replaced. A positive pregnancy test was reported 2 weeks after embryo transfer, although ultrasonography failed to demonstrate a viable pregnancy. Post abortive fetal tissue karyotyping diagnosed a male fetus with trisomy 16. This is an unusual report of preimplantation genetic diagnosis (PGD) being used for selection of males in an X-linked autosomal dominant disorder and demonstrates the value of PGD where amniocentesis or chorion villus sampling followed by abortion is not acceptable to the patient. This case also demonstrates the importance of follow-up prenatal diagnosis.- - - - - - - - - - ranking = 1.3333333333333keywords = embryo (Clic here for more details about this article) |
4/45. holoprosencephaly: the Maastricht experience.holoprosencephaly (HPE) is a developmental field defect with impaired cleavage of the embryonic forebrain as the cardinal feature. The prevalence is about 1 in 11.000-20.000 in live births and 1 in 250 during embryogenesis. In most cases, craniofacial abnormalities are associated and reflect in 80% of cases the degree of severity. The severity is of marked variability and ranges from cyclopia to minimal craniofacial dysmorphism, such as mild microcephaly with a single central incisor. The etiology of HPE is very heterogeneous and comprises environmental factors (e.g. maternal diabetes) and genetic causes. Approximately 50% of HPE cases are associated with a cytogenetic abnormality (the most common of which is trisomy 13) or a monogenic syndrome. Based on recurrent cytogenetic abnormalities, there are at least 12 genetic loci that likely contain genes implicated in the pathogenesis of HPE. Currently, four human HPE genes are known: SHH at 7q36, ZIC2 at 13q32, SIX3 at 2p21 and TGIF at 18p11.3. Over the past 13 years, 16 patients with HPE have been observed at the Department of Clinical genetics at Maastricht. Some of them are briefly presented in order to emphasize the spectral nature of HPE and the etiological heterogeneity. One patient appeared to have a partial 18p deletion due to a maternal cryptic translocation t(1:18) and, in addition, a SHH mutation. The mildest affected patient presented with microcephaly and a single maxillary incisor; she had a submicroscopic 7q deletion. Finally, we propose a protocol of etiological work-up of HPE cases.- - - - - - - - - - ranking = 0.66666666666667keywords = embryo (Clic here for more details about this article) |
5/45. A 22/22 translocation carrier with recurrent abortions demonstrated by a Giemsa banding technique,.A 22/22 Robertsonian translocation has been identified in a woman with recurrent abortions by a Giemsa banding technique. Cytogenetic studies of the embryonic tissue derived from one of her spontaneous abortions have demonstrated that the aborted fetus had a 46,XX,-22, t(22q22q) karyotype.- - - - - - - - - - ranking = 0.33333333333333keywords = embryo (Clic here for more details about this article) |
6/45. A phenotypically normal liveborn male after prenatal diagnosis of trisomy 20 mosaicism.We report on a case of prenatally diagnosed true trisomy 20 mosaicism in amniocytes. cytogenetic analysis was performed postnatally on lymphocytes and extra-embryonic tissues. For analysing uroepithelial cells we established a new cell nuclei preparation protocol for FISH (fluorescence in situ hybridization). trisomy 20 cells could not be confirmed after birth. The origin or trisomy 20 cells in amniotic fluid remains unclear. The phenotypically normal male baby is developing normal.- - - - - - - - - - ranking = 0.33333333333333keywords = embryo (Clic here for more details about this article) |
7/45. Prenatal detection of mosaic trisomy 1q due to an unbalanced translocation in one fetus of a twin pregnancy following in vitro fertilization: a postzygotic error.Complete or mosaic trisomy for all of chromosome 1q has been seen rarely in a recognized pregnancy. A patient presented with twins following in vitro fertilization (IVF). Ultrasound showed twin A to have a diaphragmatic hernia, thick nuchal fold, and subtle intracranial abnormalities. Twin B appeared normal and a thick dividing membrane was seen. amniocentesis of twin A showed a male karyotype with mosaic trisomy 1q in 57% of cells resulting from a translocation between chromosomes Yq12 and 1q12. Parental karyotypes were normal. The twins were delivered at 33 weeks. Twin A died at 1 hr of life. autopsy confirmed the left diaphragmatic hernia and hypoplastic lungs. autopsy also revealed a partial cleft palate, syndactyly of the second and third toes bilaterally, external deviation of the left 5th toe, and contractures of the index fingers bilaterally. A recent report documented formation of a chimera resulting from embryo amalgamation after IVF. Given the rarity of the cytogenetic findings in our case, we sought to determine if the mosaicism was a result of chimera formation related to the IVF. Thirteen polymorphic loci throughout the genome, in addition to four on 1q and four on 1p, were amplified by PCR. Only two alleles were observed at each of these loci in twin A, one paternal and the other maternal. We present further clinical findings of this case with a rare cytogenetic abnormality that appears to have originated from a postzygotic mitotic error and not embryo amalgamation.- - - - - - - - - - ranking = 0.66666666666667keywords = embryo (Clic here for more details about this article) |
8/45. Transcervical fetoscopic diagnosis of structural defects in four first-trimester monochorionic twin intrauterine deaths.OBJECTIVE: While chromosomal abnormalities are often the cause of early failed pregnancies, other mechanisms could be involved in monochorionic twin intrauterine deaths, that might be screened for careful morphological analysis. methods: Transcervical fetoscopy prior to instrumental evacuation of the uterus was performed in four first-trimester monochorionic twin intrauterine deaths. RESULTS: We present fetoscopic and cytogenetic findings in four cases of monochorionic twin intrauterine deaths. In the first, generalized abnormal embryonic development observed in both twins was a manifestation of trisomy 20. The second (thoracophagus) and third (acardius) pair of twins had anomalies peculiar to multiple gestations. The fourth pair of twins was remarkable because of the concordance for the observed limb-reduction defects. CONCLUSION: Malformations of first-trimester monochorionic twin intrauterine deaths might cover a wide spectrum of etiologies from abnormal chromosomes and single gene defects to rare duplication anomalies. Their detection by careful morphological analysis and the identification of a specific mechanism provides valuable information for genetic counseling and prenatal investigation in a future pregnancy.- - - - - - - - - - ranking = 0.33333333333333keywords = embryo (Clic here for more details about this article) |
9/45. Clinical, cytogenetic, and molecular findings of prenatally diagnosed mosaic trisomy 4.OBJECTIVES: To present the clinical, cytogenetic, and molecular findings of prenatally diagnosed mosaic trisomy 4. CASE: An amniocentesis was performed at 21 weeks' gestation because of maternal anxiety. cytogenetic analysis revealed mosaicism for trisomy 4, 47,XX, 4[4]/46,XX[16]. Level II ultrasound demonstrated tetralogy of fallot. Repeated amniocentesis at 23 weeks' gestation revealed 47,XX, 4[4]/46,XX[19]. The pregnancy was terminated. Phenotypic findings included tetralogy of fallot, hypertelorism, micrognathia, abnormal ears, duplicated phalanges of the left thumb, clinodactyly, and overlapping of the toes. The karyotype of the cord blood was 46,XX. Cytogenetic analyses of the multiple tissue samplings showed a karyotype of 47,XX, 4 in 40/40 cells of the amniotic membrane (amnion), and 47,XX, 4/46,XX with various levels of trisomy 4 in the cells of the liver, lungs, placenta, skin, and umbilical cord. The levels of trisomy 4 were 11/40 in the liver, 8/40 in the lungs, 31/40 in the placenta, 9/40 in the skin, and 8/40 in the umbilical cord. METHOD: The parental origin and meiotic origin of trisomy 4 were determined by examining the amniotic membrane using quantitative fluorescent polymerase chain reaction assays with polymorphic markers specific for chromosome 4. The result was consistent with a paternal meiosis I nondisjunction error. The cord blood showed a biparental inheritance. An extra paternal heterozygous allele with partial dosage increase was noted in other fetal and extraembryonic tissues studied. CONCLUSION: A diagnosis of trisomy 4 mosaicism in amniocytes indicates an increased risk for fetal abnormalities. Associated abnormal findings include congenital heart defects and anomalies of the digits and thumb. A confirmatory placental sampling may be helpful, whereas a fetal blood sampling is of a very limited value. A postnatal amnion sampling may provide additional clues to the fetal involvement of trisomy 4.- - - - - - - - - - ranking = 0.33333333333333keywords = embryo (Clic here for more details about this article) |
10/45. Confirmation of true mosaic trisomy 20 in a phenotypically normal liveborn male.A new case of prenatally detected mosaic trisomy 20 (79% trisomy 20 cells in amniocyte cultures) that was confirmed in newborn tissue is presented. A healthy male infant was delivered at term, with no dysmorphology or apparent malformations; this baby is developing normally. Twenty-five percent of foreskin and 17% of fetal cord cells also showed trisomy 20, while no trisomic cells were detected in newborn blood. High frequency mosaicism for trisomy 20 in this case was thus due to true embryonic origin. Extensive counseling and prenatal follow-up in this case led to an unaffected liveborn, and guarded optimism may be warranted for future cases of mosaic trisomy 20 detected prenatally.- - - - - - - - - - ranking = 0.33333333333333keywords = embryo (Clic here for more details about this article) |
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