1/9. Apparent confined placental mosaicism of trisomy 16 and multiple fetal anomalies: case report.trisomy 16 is frequently found confined to the placenta (confined placental mosaicism (CPM)), with a structurally normal fetus. In some cases of trisomy 16, the fetus has uniparental disomy for chromosome 16 (UPD16) which is associated with intrauterine growth restriction (IUGR) and fetal anomalies. We report a case of apparent confined placental mosaicism for trisomy 16, using standard cytogenetic techniques, but with multiple fetal abnormalities including congenital diaphragmatic hernia in which there was no evidence of UPD in the disomic tissues examined. Subsequent examination of fetal tissues using fluorescent in situ hybridization (FISH) demonstrated low levels of mosaicism for trisomy 16 in all the tissues examined. The use of FISH permits identification of mosaicism which conventional techniques may not identify.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/9. Tissue-limited mosaicism in Pallister-Killian syndrome -- a case in point.We report a case of Pallister-Killian syndrome in a term female infant. Antenatal ultrasound showed left diaphragmatic hernia and polyhydramnios. She was ventilated from birth and the diaphragm defect repaired on day 5. She had dysmorphic features, including median cleft palate, patchy frontotemporal alopecia, hypopigmented skin whorls, and bilateral profound sensorineural hearing loss. Fetal and postnatal karyotypes of peripheral lymphocytes were both normal, 46, XX. Subsequently, a skin fibroblast culture showed mosaic tetrasomy of isochromosome 12p both on G-banding and fluorescence in situ hybridization, consistent with Pallister-Killian syndrome. This case illustrates the importance of using the appropriate sample type for karyotype analysis with implications for prenatal and postnatal diagnosis.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/9. Pallister-Killian syndrome: difficulties of prenatal diagnosis.The first prenatal diagnosis of Pallister-Killian syndrome (PKS) was reported by Gilgenkrantz et al. in1985. Since this report, about 60 prenatal cases have been reported but both sonographic and cytogenetic diagnoses remain difficult. Although ultrasound anomalies such as congenital diaphragmatic hernia, polyhydramnios and rhizomelic micromelia in association with fetal overgrowth are very suggestive of the syndrome, they are inconstant and they may even be absent. The mosaic distribution of the supernumerary isochromosome 12p greatly increases these difficulties. No prenatal cytogenetic technique is sensitive enough to ensure prenatal diagnosis and false-negative results have been described on fetal blood, chorionic villi and amniocentesis. We report here two prenatal cases of PKS which illustrate the great variability of the fetal phenotype. In reviewing the 63 reported cases, we attempt to determine ultrasound indicators of the syndrome and to define a cytogenetic strategy. In cases where ultrasound indicators are present, our proposal is first to perform chorionic villus or placental sampling and then amniocentesis when the first cytogenetic result is normal. fetal blood sampling is the least indicated method because of the low frequency of the isochromosome in lymphocytes. In this cytogenetic strategy, fluorescent in situ hybridization (FISH) and especially interphase FISH on non-cultured cells increases the probability or identifying the isochromosome. A misdiagnosis remains possible when ultrasound is not contributory; the identification of new discriminating ultrasound indicators would be very helpful in this context.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
4/9. prenatal diagnosis of tetrasomy 12p by in situ hybridization: varying levels of mosaicism in different fetal tissues.prenatal diagnosis of tetrasomy 12p is complicated by the discrimination of the 12p isochromosome from the duplication 21q as well as the level of mosaicism demonstrated in the particular tissue sampled. In this disease, a high percentage of chromosomally abnormal cells are generally found in fibroblastic cells, but lymphocyte karyotypes from the same individual may be normal. We report on the pregnancy of a 37-year-old female who presented to our centre at 16 weeks' gestation for genetic amniocentesis. Sonography of the fetus revealed dextrocardia and diaphragmatic hernia. Chromosome analysis of amniocytes demonstrated mosaicism of a 47,XY, i(12p) line in 80 per cent of cells and a normal male line (20 per cent), consistent with the Pallister-Killian syndrome. Following termination, a 220 g male fetus of 18 weeks was examined. A flattened nose and low-set ears were noted. in situ hybridization with a chromosome 12 centromeric probe in lymphocytes and skin cells unequivocally confirmed the karyotype and showed the presence of a single centromere in the abnormal chromosome, suggesting a true isochromosome. Chromosome analysis of various fetal tissues was performed and the following percentages of abnormal cells were found: skin 100 per cent, chorion 50 per cent, placenta 30 per cent, and blood 80 per cent. The high frequency of tetrasomic cells in fetal blood at this early gestational age is noteworthy, since most reports of this syndrome show a very low percentage of abnormal cells postnatally.- - - - - - - - - - ranking = 5keywords = hybridization (Clic here for more details about this article) |
5/9. Congenital diaphragmatic hernia in wagr syndrome.wilms tumor, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome is a contiguous gene deletion syndrome involving the wilms tumor 1 gene (WT1), the paired box gene 6 (PAX6), and possibly other genes on chromosome 11p13. WT1 is required for normal formation of the genitourinary system and the high incidence of wilms tumor and genitourinary anomalies found in patients with WAGR are attributed to haploinsufficiency of this gene. It has been hypothesized that WT1 also plays an important role in the development of the diaphragm. During mammalian embryonic development, WT1 is expressed in the pleural and abdominal mesothelium that forms part of the diaphragm. Furthermore, mice that are homozygous for a deletion in the mouse homolog of WT1 have diaphragmatic hernias. case reports describing congenital diaphragmatic hernias in infants with Denys-Drash and Frasier syndromes, both of which can be caused by mutations in WT1, provide additional support for this hypothesis. We report an infant with aniridia, bilateral cryptorchidism, vesicoureteral reflux, and a right-sided Morgagni-type diaphragmatic hernia. G-banded chromosome analysis revealed a deletion of 11p12-p15.1. Breakpoint regions were refined by fluorescence in situ hybridization (FISH) and deletion of the WAGR critical region, including WT1, was confirmed. A review of the medical literature identified a second patient with a deletion of 11p13, a left-sided Bochdalek-type diaphragmatic hernia, and anomalies that suggest a diagnosis of WAGR including bilateral microphthalmia, a small penis, bilateral cryptorchidism, and a hypoplastic scrotum. These cases demonstrate that congenital diaphragmatic hernia can be associated with wagr syndrome and suggest that deletions of WT1 may predispose individuals to develop congenital diaphragmatic hernia.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
6/9. Molecular characterization of del(8)(p23.1p23.1) in a case of congenital diaphragmatic hernia.A 36-week-old fetus was referred to the medical center because of his cystic mass and fluid in left thoracic cavity, and was delivered by cesarean section to manage neonatal problems at 37 weeks of gestation. Emergent surgical repair of the left diaphragmatic hernia was performed, but severe hypoxia persisted, and he expired on the following day. Chromosome analysis of cultured amniotic fluid cells indicated 46,XY,del(8)(p23.1p23.1). This is the fourth case of 8p23.1 deletion associated with diaphragmatic hernia. Microarray comparative genomic hybridization analysis using dna of cultured amniotic fluid cells showed that six clones were deleted, which were mapped to the region between two low copy repeats (LCRs) at 8p23.1 previously described. Microsatellite analysis revealed that the deletion was of paternal origin, and his parents did not carry 8p23.1 polymorphic inversion. These data strongly suggested that the 8p23.1 interstitial deletion should have arisen through a different mechanism from that of inv dup del(8p) whose structural abnormality is always of maternal origin and accompanies heterozygous 8p23.1 polymorphic inversion in mother.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
7/9. Findings from aCGH in patients with congenital diaphragmatic hernia (CDH): a possible locus for Fryns syndrome.Congenital diaphragmatic hernia (CDH) is a common and often devastating birth defect that can occur in isolation or as part of a malformation complex. Considerable progress is being made in the identification of genetic causes of CDH. We applied array-based comparative genomic hybridization (aCGH) of approximately 1Mb resolution to 29 CDH patients with prior normal karyotypes who had been recruited into our multi-site study. One patient, clinically diagnosed with Fryns syndrome, demonstrated a de novo 5Mb deletion at chromosome region 1q41-q42.12 that was confirmed by FISH. Given prior reports of CDH in association with cytogenetic abnormalities in this region, we propose that this represents a locus for Fryns syndrome, a Fryns syndrome phenocopy, or CDH.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
8/9. Congenital diaphragmatic hernia associated with duplication of 11q23-qter.Congenital diaphragmatic hernia (CDH) is a relatively common birth defect with a high mortality. Although little is known about its etiology, there is increasing evidence for a strong genetic contribution. Both numerical and structural chromosomal abnormalities have been described in patients with CDH. Partial trisomy 11q and partial trisomy 22 associated with the common t(11;22) has been reported in several cases of CDH. It has been assumed that the diaphragmatic defect seen in these individuals was primarily due to duplication of material from chromosome 22q11. However, in this report we describe a family with a t(11;12) in which one of two brothers with partial trisomy 11q has a left sided posterolateral CDH. This is the second case of CDH in partial trisomy 11q due to an unbalanced translocation other than t(11;22). Using array-based comparative genomic hybridization and fluorescent in situ hybridization, we mapped the breakpoints in both brothers and their mother who is a balanced translocation carrier. Our results suggest that duplication of one or more genes on a approximately 19 Mb region of 11q23.3-qter predisposes to the development of CDH. These effects may be the primary cause of CDH in individuals t(11;22) or may be additive to effects from the duplication of chromosome 22 material. We also conclude that the partial trisomy 11q syndrome has a variable phenotype and that CDH should be added to the spectrum of anomalies that can be present in this syndrome.- - - - - - - - - - ranking = 2keywords = hybridization (Clic here for more details about this article) |
9/9. Lethal Pallister-Killian syndrome: phenotypic similarity with Fryns syndrome.The Pallister-Killian syndrome is a sporadic multiple congenital anomaly syndrome characterized by "coarse" face, profound mental retardation, and epilepsy. chromosomes of peripheral lymphocytes are usually normal, but tissue cultures show varying degrees of mosaicism for isochromosome 12p. In babies who die neonatally of severe malformations, including diaphragmatic hernia, and who also have a "coarse" face, acral hypoplasia, and other internal anomalies, Fryns syndrome is more likely to be suspected than Pallister-Killian syndrome, especially if karyotyping is unavailable or if peripheral lymphocytes have a normal chromosome constitution. An initial diagnosis of Fryns syndrome had to be modified in 3 successive newborn infants since chromosome analysis or in situ hybridization with a chromosome 12 probe on kidney tissue demonstrated the mosaic aneuploidy characteristic of Pallister-Killian syndrome. These 3 patients confirm that a similar pattern of malformations can be present in both conditions at birth. It consists of "coarse" face, acral hypoplasia, diaphragmatic hernia, and other defects. Newborn infants who present this phenotype, but lack a conclusively normal chromosome test, may not have Fryns syndrome. A diagnosis of Fryns syndrome should be made carefully to avoid the risk of inappropriate genetic counseling.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |