Showing papers on "Ring chromosome published in 1980"
01 Jan 1980
TL;DR: Some of the problems and perspectives of the SCE test are explored and some of the results obtained so far are reviewed.
Abstract: The recent introduction of the sister-chromatid exchange (SCE) test has revolutionized the cytogenetic approach to the identification of biologically hazardous chemicals. Increasingly, laboratories are turning to this technique in preference to scoring chromosome aberrations. This chapter explores some of the problems and perspectives of the SCE test and reviews some of the results obtained so far.
101 citations
TL;DR: A ring 12 chromosome was found in a male child with minor phenotypic alterations and since there is no other case of a ring 12 in the literature, it was found to be normal.
Abstract: A ring 12 chromosome was found in a male child with minor phenotypic alterations. No obvious loss of chromosome material was detected. Since there is no other case of a ring 12 in the literature, it w
43 citations
TL;DR: Cytogenetic analysis of a 15 month old girl evaluated for severe developmental delay and acral skeletal hypoplasia revealed a predominant 46,XX,r(15) karyotype, and Cellular mosaicism for chromosome 15 aneuploidy most likely accounts for the patient's phenotypic abnormalities.
Abstract: Cytogenetic analysis of a 15 month old girl evaluated for severe developmental delay and acral skeletal hypoplasia revealed a predominant 46, XX, r(15) karyotype. Prophase banding analysis showed minimal deletion of the ring chromosome (breakpoints pl2 and q26), while silver staining showed it to have an active nucleolus organizing region, multiple abnormal secondary configurations, and decreased satellite association. Although there was no spontaneous instability in the rest of the karyotype, gentian violet-induced chromosome breakage was significantly increased. The rate of spontaneous sister chromatid exchange was not elevated. Cellular mosaicism for chromosome 15 aneuploidy most likely accounts for the patient’s phenotypic abnormalities.
36 citations
TL;DR: It became clear that the study of maternal effects on mutagenized sperm represents an efficient tool to analyze the genetic control of mutagenesis in the eukaryotic genome of Drosophila melanogaster.
Abstract: Experimental evidence indicates a polygenic control of mutagenesis in Drosophila melanogaster. In oocytes chromosome aberrations detected as half-translocations or dominant lethals depend on a repair system which in a number of genetically nonrelated strains shows different repair capacities. Sister chromatid exchanges (SCE) are easily studied as ring chromosome losses. They develop through a genotype controlled mechanism from premutational lesions. Stocks with particular pairs of third chromosomes were discovered in which increased sensitivity of larvae to the toxic effects of a monofunctional alkylating agent (MMS) correlates with high frequencies of x-ray induced SCE’s.
29 citations
TL;DR: Detailed analysis by G banding revealed the loss of the whole of band q21 and part of bands q13 and q22 in a child with congenital malformations and a de novo interstitial deletion of the long arm of chromosome 4.
Abstract: A child with congenital malformations and a de novo interstitial deletion of the long arm of chromosome 4 is described. Detailed analysis by G banding revealed the loss of the whole of band q21 and part of bands q13 and q22. The clinical abnormalities are quite dissimilar from those features described in other cases of partial 4q monosomy, which generally appear to result from the deletion of more distally placed segments of the chromosome.
23 citations
TL;DR: Cytogenetic analysis of an 8-month-old Japanese girl with moderate retardation of physical development was performed and a ring chromosome 10, 46,XX,r(10)(p15→q26), was found and she had short stature, mildly stubby nose, antimongoloid slants, and moderately protruding ears.
Abstract: Cytogenetic analysis of an 8-month-old Japanese girl with moderate retardation of physical development was performed and a ring chromosome 10, 46,XX,r(10)(p15→q26), was found. She had short stature, mildly stubby nose, antimongoloid slants, and moderately protruding ears. The extremities showed erythrocyanosis, oedema, and pigmentation. Lansky et al1 was the first to describe ring chromosome 10 with a Turner-like phenotype. Only two other cases2 3 have been reported so far and little is known about this syndrome. This is the report of a fourth case.
19 citations
TL;DR: A case of r(21) with stigmata of atypical Down syndrome with double-sized ring chromosomes and SOD-1 activity revealed only slight elevation is presented.
Abstract: A case of r(21) with stigmata of atypical Down syndrome is presented. Karyotype of the proposita was determined as 45,XX,-21/46,XX,-21, +r(21)/47,XX,-21,+r(21),+(21). Most ring chromosomes showed double-sized ring chromosomes, which were trisomic for 21p11-21q22.3 and monosomic for 21q22.3-qter. SOD-1 activity revealed only slight elevation. The mechanism of ring formation is discussed.
17 citations
TL;DR: A 13 month-old girl with failure to thrive developmental delay, and dysmorphic features with Epicanthal folds, mildly cupped, apparently low-set ears, highly arched palate, short neck with low hairline, clinodactyly, and single crease of left 5th finger is studied.
Abstract: We have studied a 13 month'old girl with failure to thrive, developmental delay, and dysmorphic features. At 13 months, the weight'age was 1 month, length'age was 3 months and head circumference was at the 3rd centile for 3 months. Physical findings were: Epicanthal folds, mildly cupped, apparently low'set ears, highly arched palate, short neck with low hairline, clinodactyly, and single crease of left 5th finger. The modal chromosome number was 46. Trypsin-G banding identified a ring chromosome 12; Karyotype was 46,XX,r(12)(p13q24).
13 citations
TL;DR: A ring chromosome 2 mosaic was found in a newborn female with severe intrauterine growth retardation (IUGR), postnatal growth failure, and a few minor abnormalities, which indicates that the chromosome abnormality arose after conception.
Abstract: A ring chromosome 2 mosaic [46,XX/46,XX,r(2)(p25q37)] was found in a newborn female with severe intrauterine growth retardation (IUGR), postnatal growth failure, and a few minor abnormalities. Psychomotor development has been normal to 19 months old. A ring chromosome 2 is present in 77.8% of the nuclei examined and is not found in the parents or a sibling. G- and R-banding reveal the break points to be p25q37. The presence of a normal cell line indicates that the chromosome abnormality arose after conception.
11 citations
TL;DR: An infant with ring 15 is discussed, a product of the second pregnancy for her mother, who was 161cm tall and 27 years of age at that time and the father was 168 cm tall and 35 years ofAge.
Abstract: Ring chromosomes are rare in man. Friedrich and Nielson1could not find one ring in the compiled data of the cytogenetic screening of 31,801 consecutive live-born children. Hecht and Vlietinck,2as well as Zdansky et al,3claim that the phenotypic and cytogenetic differences among even "identical rings" do not permit an accurate delineation of an identifiable syndrome. On the other hand, certain ring chromosome syndromes (ring 1, 6, 9,13, 15, 21, and 22) appear already in textbooks4as separate clinical entities. To solve the controversy, more case reports seem warranted. Therefore, we discuss an infant with ring 15. Report of a Case.—This girl was a product of the second pregnancy for her mother, who was 161 cm tall and 27 years of age at that time. The father was 168 cm tall and 35 years of age. Illness, exposure to drugs, and roentgenograms during the pregnancy were
11 citations
TL;DR: A case of ring chromosome 14 in a 12‐year‐old girl, showing mental retardation, epilepsy and minor somatic abnormalities, is described and compared with five previously reported cases with the same chromosome aberration.
Abstract: Iselius, L, Ritzen, M, Hui, T-H, Olsson, K and Eklof, O (Departments of Clinical Genetics, Pediatrics, Ophthalmology and Pediatric Radiology, Karolinska Hospital, Stockholm, Sweden) Ring chromosome 14 in a mentally retarded girl Acta Paediatr Scand, 69:803, 1980—A case of ring chromosome 14 in a 12-year-old girl, showing mental retardation, epilepsy and minor somatic abnormalities, is described and compared with five previously reported cases with the same chromosome aberration
TL;DR: It is suggested that fertility per se may not be affected by deficiencies of the distal part of Xq, and it is confirmed that women heterozygotes for partial deficiency of the short arm of an X chromosome are fertile.
Abstract: A 45,X/46,X,r(X) mosaicism was found in a mother and daughter. Characterisation of the ring by banding studies showed that breakpoints had occurred at bands Xp13 and Xq27. It is confirmed that women heterozygotes for partial deficiencies of the short arm of an X chromosome are fertile. Although the mother developed secondary amenorrhoea at the age of 29, it is suggested that fertility per se may not be affected by deficiencies of the distal part of Xq.
TL;DR: Two male fetuses and their mothers, referred for amniocentesis because of high levels of AFP in their blood, were found to carry an anomalous chromosome 5 with a large heterochromatic segment in the long arm.
Abstract: Two male fetuses and their mothers, referred for amniocentesis because of high levels of AFP in their blood, were found to carry an anomalous chromosome 5 with a large heterochromatic segment in the long arm. One of the fetuses had an additional ring chromosome.
TL;DR: A 5 1/2-year-old girl is reported with a tiny supernumerary chromosome fragment found in mosaic and the ring nature of the tiny fragment was demonstrated by the detection of the characteristic products of a ring chromosome.
Abstract: We report a 5 1/2-year-old girl with a tiny supernumerary chromosome fragment found in mosaic. The ring nature of the tiny fragment was demonstrated by the detection of the characteristic products of a ring chromosome. The clinical consequence of a ring chromosome and the impact of finding a supernumerary chromosome fragment, especially in the practice of prenatal chromosome diagnosis, are discussed.
TL;DR: The patient was a male infant, born to phenotypically normal, non-consanguineous parents, who had an abnormal phenotype, mental retardation, and chromosome mosaicism 46,XY/47,XY,+r.
Abstract: A case of agenesis of the corpus callosum with a chromosomal abnormality is reported. The patient was a male infant, born to phenotypically normal, non-consanguineous parents. He had an abnormal phenotype, mental retardation, and chromosome mosaicism 46,XY/47,XY,+r. Chromosomal analysis of both parents showed a normal karotype. The origin of the small ring chromosome could not be determined and it is difficult to relate the phenotype of the infant to the cytogenetic findings.
TL;DR: A 6-year-old girl whose neuropathological findings included low brain weight, abnormal gyral development, and heterotopic neurons is described and the significance of these findings in regard to other retardation syndromes is discussed.
Abstract: Despite the fact that mental retardation, microcephaly, seizures, and hyperactivity are common in patients with ring chromosome 4, little has been written about the underlying neuropathology. We describe a 6-year-old girl whose neuropathological findings included low brain weight, abnormal gyral development, and heterotopic neurons. The significance of these findings in regard to other retardation syndromes is discussed.
Journal Article•
TL;DR: A ring 6 chromosome was detected in a 18 months old boy who was a dwarf with psychomotor retardation, morphological anomalies i.e. microcephaly, bird head shaped facies with large ears, arched palate and micrognathia.
Abstract: A ring 6 chromosome was detected in a 18 months old boy The patient was a dwarf with psychomotor retardation, morphological anomalies ie microcephaly, bird head shaped facies with large ears, arched palate and micrognathia A survey of 9 others cases collected in the medical literature permit to propose a specific phenotype for this chromosomal abnormality
TL;DR: Silver-staining has been used to identify the nucleolus organizer regions (NORs) in the bharal that show homology with sheep, goat, cattle and aoudad and results in a ‘ring’ chromosome.
Abstract: Silver-staining has been used to identify the nucleolus organizer regions (NORs) in the bharal. These show homology with sheep, goat, cattle and aoudad. The association of the NORs on both telomeres of chromosome 3 results in a ‘ring’ chromosome.