1/19. wolf-hirschhorn syndrome due to a 3:1 segregation of a maternal balanced t(4;15)(p16.3;q11) translocation.The wolf-hirschhorn syndrome (WHS) is characterized by severe pre- and postnatal growth retardation, specific pattern of dysmorphisms, and severe developmental delay. These clinical findings are the result of a deletion within the short arm of chromosome 4. Most cases occur de novo and are of paternal origin. Cases due to a balanced translocation are mostly of maternal origin and the deletion of distal 4p, including the WHS critical region, is often combined with a duplication of the other chromosomal segment involved in the rearrangement. Here, we report on a newborn female infant with WHS and pure tertiary monosomy due to a 3:1 segregation of a balanced maternal 4;15 translocation. In this context, importance of fluorescence in situ hybridization (FISH) with specific probes to determine the exact breakpoints in unbalanced chromosomal rearrangements with breakpoints localized around known microdeletion syndromes is emphasized.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
2/19. Fusion of 9 beta-satellite and telomere (TTAGGG)n sequences results in a jumping translocation.A newborn was found to have an isochromosome for the short arm of chromosome 9, i(9p) and a jumping translocation of the whole long arm. In 94.4% metaphases, 9q was fused to the telomere of chromosome 19p and, in 5.6% of metaphases, 9q was fused to the telomere of chromosome 8p. The net result was trisomy for the short arm of chromosome 9. With the pan telomere probe, fluorescent in situ hybridization (FISH) investigations found an interstitial telomere on the der(19) and der(8). The 9 beta and classical satellite probes gave a signal only on the long arm of chromosome 9 involved in the jumping translocation. The 9 alpha satellite probe hybridized to i(9p) and not to the other derivative chromosomes. A combination of chromosome 9 (red) and chromosome 19 (green) paint probes used to rapidly screen metaphases for the jumping translocation found 88 metaphases had a der(19)t(9;19) and 4metaphases had a der(8)t(8;9). For the first time, the junction of a jumping translocation has been shown to involve the telomere sequence (TTAGGG)n and beta-satellite sequences by FISH. In this paper, we also review the simultaneous occurrence of an isochromosome for the short arm and translocation of the whole long arm and constitutional jumping translocations.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
3/19. prenatal diagnosis of a de novo ring chromosome 11.ring chromosomes are uncommon findings in prenatal diagnosis. Growth retardation is the most significant manifestation, in particular among patients with rings of larger chromosomes. A 30-year-old gravida 1, para 0 white woman was referred for genetic counseling because of maternal anxiety. cytogenetic analysis of amniotic fluid cells at 16 weeks gestation revealed an abnormal mosaic female chromosome complement; 46,XX,r(11)(p15q25)[14]/45,XX,-11[7]. The ring 11 showed no detectable loss of chromosomal material at 450 band level. Both parents had a normal karyotype. fluorescence in situ hybridization demonstrated intact subtelomeric regions in the ring chromosome. A targeted ultrasound evaluation at the time of consultation suggested no significant abnormalities. The parents were counseled and subsequently decided to terminate the pregnancy. The autopsy revealed an immature female fetus with abnormal craniofacial features including brachycephaly, low-set ears and hypertelorism, bicornuate uterus, and calcifications in the renal tubules. The abnormal phenotypes could be a consequence of the ring instability, submicroscopic deletion, and/or alteration of genetic material at the site of fusion.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
4/19. Increased fetal nuchal fold leading to prenatal diagnosis of ring chromosome 15.We report on the prenatal diagnosis of ring chromosome 15 in a fetus with increased nuchal fold and intrauterine growth restriction (IUGR). A 27-year-old woman gravida 2, para 1 had normal maternal serum screen tests in the early second trimester of the index pregnancy. Fetal nuchal fold thickening up to 8 mm was incidentally found during the routine obstetric ultrasound scan at 20 weeks' gestation. amniocentesis was undertaken and the fetal karyotype was found to be 46,XY,r(15) on cytogenetic study. fluorescence in situ hybridization (FISH) using a telomeric probe of chromosome 15 demonstrated a terminal deletion on the q arm of the ring-shaped chromosome 15. This is the first report of a prenatally diagnosed case of ring chromosome 15. Moreover, nuchal fold thickness in the second trimester may have a role in its prenatal diagnosis.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
5/19. Postnatal overgrowth by 15q-trisomy and intrauterine growth retardation by 15q-monosomy due to familial translocation t(13;15): dosage effect of IGF1R?We report a 4-year-old boy, a 6-month-old girl, and a 17-week-old fetus all with a chromosomal imbalance derived from a balanced translocation t(13;15)(q34;q26.1) of their father. The boy had a partial trisomy for 15q26.1-qter (46,XY,der(13)t(13;15)(q34;q26.1)) and postnatal overgrowth, as well as craniosynostosis, facial anomalies, and finger joint contractures, while the girl with the same chromosomal aberration did not show overgrowth, although she had similar craniofacial and skeletal abnormalities. The fetus had a partial monosomy for 15q26.1-qter and intrauterine growth retardation (IUGR). fluorescence in situ hybridization (FISH) analysis with a BAC clone covering the insulin-like growth factor 1 receptor gene (IGF1R) that is located to 15q25-q26 revealed three copies in the boy, one copy in the fetus, and two copies in their phenotypically normal father. Since deletion of IGF1Rhas repeatedly been reported to be associated with IUGR, it is tempting to speculate that the dosage of IGF1R may have determined growth in these children.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
6/19. prenatal diagnosis of mosaic ring chromosome 22 associated with cardiovascular abnormalities and intrauterine growth restriction.OBJECTIVES: To present the prenatal diagnosis and perinatal findings of mosaic ring chromosome 22. CASE: amniocentesis was performed at 18 gestational weeks because of an advanced maternal age. cytogenetic analysis of the cultured amniotic fluid cells revealed mosaicism for ring chromosome 22, 45,XX,-22[6]/46,XX,r(22)(p13q13.31)[15]. Abnormal fetal sonographic findings included small for gestational age, a ventricular septal defect, and truncus arteriosus. The pregnancy was terminated. Additional phenotypic findings included hypertelorism, epicanthal folds, and abnormal ears. cytogenetic analysis of the cord blood lymphocytes revealed a complex mosaic karyotype, 45,XX,-22[7]/46,XX,r(22)(p13q13.31)[82]/46,XX,idic r(22)(p13q13.31;p13q13.31)[11]. cytogenetic analysis of the hepatocytes also revealed mosaic r(22) with mosaicism for idic r(22) and monosomy 22. The deletion of distal 22q and the duplication of 22q11.2 on idic r(22), and the distal 22q deletion on r(22) were demonstrated by fluorescent in situ hybridization (FISH) analysis using 22q terminal probes at 22q13 and a digeorge syndrome critical region probe at 22q11.2. The breakpoint on distal 22q13 and the extent of the duplication of 22q on idic r(22) was determined by examining polymorphic markers specific for chromosome 22 using quantitative fluorescent polymerase chain reaction assays. The chromosomal aberration was of maternal origin. CONCLUSION: Molecular and FISH studies allow a better delineation of some prenatally detected aneuploidy syndromes and help elucidate the genetic pathogenesis. Fetuses having mosaic r(22) with a low level mosaicism for r(22) duplication/deletion may present cardiovascular abnormalities and intrauterine growth restriction on prenatal ultrasound.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
7/19. prenatal diagnosis of de novo terminal deletion of chromosome 7q.OBJECTIVES: To present the prenatal diagnosis and perinatal findings of a de novo terminal deletion of chromosome 7q. CASE: amniocentesis was performed at 21-weeks gestation owing to a positive result of maternal serum multiple-marker screening. The 30-year-old woman, gravida 2, para 1, had a maternal serum multiple-marker screening test at 18-weeks gestation. The risk of down syndrome was 1/11 calculated from the gestational age, maternal age, a maternal serum alpha-fetoprotein level of 1.026 multiples of the median (MOM), and a maternal serum free beta-human chorionic gonadotrophin (hCG) level of 8.678 MoM. cytogenetic analysis of the cultured amniotic fluid cells revealed a de novo terminal deletion of 7q, 46,XX,del(7)(q35). ultrasonography showed intrauterine growth restriction, microcephaly, and tetralogy of fallot. The pregnancy was terminated subsequently. Grossly, the placenta was normal. On autopsy, the proband additionally manifested a prominent forehead, hypertelorism, epicanthus, upslanting palpebral fissures, a flat and broad nasal bridge, micrognathia, large low-set ears, overriding toes, and a normal brain. radiography demonstrated a normal spine. fluorescence in situ hybridization analysis demonstrated a 7q terminal deletion. Genetic marker analysis showed a maternally derived terminal deletion of chromosome 7(q35-qter). CONCLUSION: Fetuses with a de novo 7q terminal deletion may be associated with a markedly elevated maternal serum hCG level and abnormal sonographic findings of intrauterine growth restriction, microcephaly, and congenital heart defects in the second trimester.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
8/19. Prenatal sonographic patterns in six cases of Wolf-Hirschhorn (4p-) syndrome.This multicentric study presents 6 cases of wolf-hirschhorn syndrome (deletion of 4p) detected after a sonographic prenatal diagnosis of early intrauterine growth retardation with fetal abnormalities. Standard karyotyping on regular G-banding during pregnancy was normal in half of the cases. Fortunately, the associated sonographic signs of a typical face, cystic cerebral lesions, midline fusion defects and bilateral renal hypoplasia may help to refine specific indications for high-resolution banding and molecular analysis by in situ hybridization.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
9/19. Inherited ring chromosome 8 without loss of subtelomeric sequences.We report the first case of inherited ring chromosome 8 syndrome without loss of subtelomeric sequences. The proband is a 6 1/2-year-old boy with short stature, microcephaly, mild mental retardation, and behavioral problems including hyperactivity and attention deficit. His mother presented the same physical features but intelligence was normal. family history also revealed an uncle and a grandmother, with short stature and microcephaly. Moderate mental retardation was reported in the uncle. Karyotypes and fluorescence in situ hybridization (FISH) analyses were performed on peripheral blood lymphocytes for both child and mother. The child's karyotype was reported as 46,XY,r(8)(p23q24.3)[24]/45,XY,-8[2] and the mother's karyotype 46,XX,r(8)(p23q24.3)[22]/45,XX,-8[2]/47,XX,r(8)(p23q24.3), r(8)(p23q24.3)[1]. FISH studies showed no deletion of subtelomeric sequences for both child and mother indicating that no or little chromosomal euchromatic material has been deleted. These findings indicate that ring chromosome 8 without loss of subtelomeric sequences can be inherited and that carriers in a same family present with cognitive function ranging from mild mental retardation to normal intelligence.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
10/19. Molecular cytogenetic characterization of ring chromosome 15 in three unrelated patients.We report molecular cytogenetic characterization of ring chromosome 15 in three unrelated male patients with the karyotype 46,XY,r(15). One was a stillborn child with several malformations, and the other two cases showed pre- and postnatal growth retardation and developmental delay, common features for ring chromosome 15 syndrome. One of these patients also displayed clinical features resembling prader-willi syndrome (PWS). To delineate the extent of the deletion on chromosome 15, we have carried out fluorescence in situ hybridization (FISH) using bacterial artificial chromosomes (BACs) mapping to the distal long arm of chromosome 15. The deletion breakpoints clustered within a 4.5-6.5 Mb region proximal to the 15q telomere. Two deletions involved the same known genes, while the largest deletion observed in the stillborn child involved three additional genes, including the COUP-TFII gene, which has been suggested to play a role in heart development. The heart malformations, which are observed in this patient, are thus likely to be due to hemizygosity/haploinsufficiency of the COUP-TFII gene. In all three patients, the insulin-like growth factor i receptor gene (IGF1R) gene was deleted supporting the association between IGF1R and growth retardation seen in ring chromosome 15 syndrome.- - - - - - - - - - ranking = 1keywords = hybridization (Clic here for more details about this article) |
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