Showing papers on "Ring chromosome published in 1977"
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TL;DR: It is suggested that the clinical features associated with this ring chromosome are more likely to be the result of the effects of a diploid/monosomy 4/polysomy 4 mosaicism than to the deficiency of the telomeric regions of the chromosome.
Abstract: A mentally and physically retarded boy with a 46,XY,ring (4) (p16q35) chromosome complement is described Chromosome banding showed that the amount of chromosome material deleted from the ring chromosome 4 was minimal, apparently no more than the telomeres Chromosomal aberrations appear to be restricted to the production of double-sized dicentric rings, and aneuploidy The mosiacism resulting from the behavioural peculiarities of ring chromosomes is described as dynamic mosaicism It is suggested that the clinical features associated with this ring chromosome are more likely to be the result of the effects of a diploid/monosomy 4/polysomy 4 mosaicism than to the deficiency of the telomeric regions of the chromosome
39 citations
TL;DR: A 5-day-old male child presenting some features of Wolf syndrome is studied, and the analysis of his karyotype showed a ring chromosome of B group, which was present in most of the cells examined.
Abstract: A 5-day-old male child presenting some features of Wolf syndrome is studied. The analysis of his karyotype by usual techniques showed a ring chromosome of B group. This chromosome was present in most of the cells examined. By GTG banding it was identified as a No.4 chromosome, the karyotype being: 46,XY,r(4),(p15→q35). The analysis was completed by familial cytogenetic and dermatoglyphic studies.
23 citations
TL;DR: Cytogenetic analysis of peripheral leucocytes of a 9-year-old girl presenting with retardation of physical development indicated mosaicism for a ring 10 chromosome.
Abstract: Cytogenetic analysis of peripheral leucocytes of a 9-year-old girl presenting with retardation of physical development indicated mosaicism for a ring 10 chromosome. Serum aspartate transaminase was within normal limits. A survey of eight markers failed to show syntenic relations with chromosome 10.
21 citations
TL;DR: Cytogenetic investigation of a 4-year-old boy with ambiguous external genitalia revealed a 46,XY,r(9)(p2q3) complement, which is common to other reported r(9) cases.
Abstract: Cytogenetic investigation of a 4-year-old boy with ambiguous external genitalia revealed a 46,XY,r(9)(p2q3) complement. The patient displayed some phenotypic characteristics common to other reported r(9) cases, in addition to ambiguous external genitalia.
19 citations
TL;DR: Mosaicism of cells with a normal karyotype or with a ring chromosome no. 15 was found in a girl with hypoplasia of the thumbs, club feet, mental retardation, and short stature, which seems to be a feature of this chromosomal aberration.
Abstract: Mosaicism of cells with a normal karyotype or with a ring chromosome no. 15 was found in a girl with hypoplasia of the thumbs, club feet, mental retardation, and short stature, which seems to be a feature of this chromosomal aberration.
15 citations
TL;DR: The mitotic chromosome behavior of the Brazilian semi-dwarf wheat cultivar IAS 54 (Triticum aestivum L. em Tell) is described and the possibility that pretreatment was responsible for the abnormalities was eliminated.
Abstract: The mitotic chromosome behavior of the Brazilian semi-dwarf wheat cultivar IAS 54 (Triticum aestivum L. em Tell) is described. In root tip cells dicentrics, fragments, isochromosomes, a satellite tandemly duplicated, chromatid exchanges, aneuploidy, ring chromosomes and breaks in almost all chromosomes of the complement were observed. Since anaphase cells that were not pretreated showed bridges, disorderly condensation and micronuclei, the possibility that pretreatment was responsible for the abnormalities was eliminated. Other possible genetic factors and virus infection as causal agents were discussed.
9 citations
TL;DR: A ring chromosome 8 was found in peripheral blood cells in a boy, whose chromosomes were studied because of multiple congenital anomalies, and examination of skin cells revealed a 46,XY/46,XY,8r pattern.
Abstract: A ring chromosome 8 was found in peripheral blood cells in a boy, whose chromosomes were studied because of multiple congenital anomalies. Examination of skin cells revealed a 46,XY/46,XY,8r pattern. Application of several banding techniques suggested a duplication of the most distal bands of both arms in the ring. The terminal end of 8q appeared to have been retained as could be shown by R-banding. The anaesthesia and surgery the mother underwent in the first month of her pregnancy is considered as a possible cause of the chromosome abnormality.
9 citations
Journal Article•
TL;DR: An r(14) is observed in monozygotic twins, with psychomotor retardation and no obvious somatic malformation.
Abstract: An r(14) is observed in monozygotic twins, with psychomotor retardation and no obvious somatic malformation.
9 citations
TL;DR: A mentally retarded and malformed girl was described and clinical features were compared with those of cases with either trisomy or partial monosomy 13.
Abstract: A mentally retarded and malformed girl is described. Her karyotype was 46, XX, −13, +rob(13q 13q)/46, XX, r(13) (p11q34),i.e., she was trisomic for a 13 in about 75% of the cells and partially monosomic for a distal part of 13q in about 25% of the cells. Clinical features were compared with those of cases with either trisomy or partial monosomy 13.
8 citations
TL;DR: A 27-year-old woman with secondary amenorrhea and some of the somatic stigmata of Turner's syndrome was found to have a ring chromosome, which suggests the absence or decrease of some factor normally produced by the ovarian follicle which modulates the release of FSH in response to LH-RH.
Abstract: A 27-year-old woman with secondary amenorrhea and some of the somatic stigmata of Turner′s syndrome was found to have a ring chromosome. Laparoscopy and ovarian biopsy showed hypoplastic ovaries and an absence of primordial follicles. Endocrine evaluation showed a normal 24-h mean LH level (12.5 mlU/ml), an elevated FSH level (28 mlU/ml) and a normal plasma estradiol level (64 pg/ml). The augmented FSH and normal LH response to LH-RH is similar to what is found in men with germinal cell aplasia (Sertoli-cell only). The synchronous initiation of normal LH and abnormally augmented FSH secretory episodes in this patient suggests the absence or decrease of some factor normally produced by the ovarian follicle which modulates the release of FSH in response to LH-RH.
7 citations
Journal Article•
TL;DR: A ring chromosome derived from a No. 4 chromosome was found in the complement of an 8-year-old boy with mental retardation and growth retardation, and developmental defects characteristic of 4p deletion.
Abstract: A ring chromosome derived from a No. 4 chromosome was found in the complement of an 8-year-old boy with mental retardation and growth retardation and developmental defects characteristic of 4p deletion. Break points were at 4p15 and 4q35.
TL;DR: A supernumerary small ring chromosome was found in 30% of cultured peripheral leucocytes and 50% of skin fibroblasts in a 6-year-old boy with mild mental retardation and midline cleft palate; thus the origin of the ring chromosome could not be determined.
Abstract: A supernumerary small ring chromosome was found in 30% of cultured peripheral leucocytes and 50% of skin fibroblasts in a 6-year-old boy with mild mental retardation and midline cleft palate. The extra chromosome appeared to carry a densely staining region on Giemsa banding. The banding patterns of the remaining 46 chromosomes were normal. C banding indicated that the ring chromosome contained mainly centromeric constitutive heterochromatin. Chromosome analysis of both parents showed normal karyotypes by both conventional and banding techniques; thus the origin of the ring chromosome could not be determined.
TL;DR: The patient was a female infant, born to healthy, consanguineous young parents, who presented the classical features of the syndrome and chromosome mosaicism 46, XX/47, XX, +r(?).
Abstract: A case of leprechaunism with a chromosomal abnormality is reported. The patient was a female infant, born to healthy, consanguineous young parents. Her course was one of extreme marasmus, with death at 3 months of age. She presented the classical features of the syndrome and chromosome mosaicism 46, XX/47, XX, +r(?). It was not possible to identify the origin of the extra ring chromosome. It is difficult to establish the role of such a cytogenetic finding in the aetiology of the syndrome.
Journal Article•
TL;DR: In general, the most useful indicator of radiation damage at the cellular level is the occurrence of ring, dicentric, fragment, and fragment ring chromosomes.
Abstract: Monitoring health-related radiation damage is important for the future, and a system to detect chromosomal aberrations associated with radiation is extremely useful for monitoring populations exposed to radiation. In general, the most useful indicator of radiation damage at the cellular level is the occurrence of ring, dicentric, fragment, and fragment ring chromosomes.
TL;DR: Studies of a nine-year-old female patient who presented with coarse facial features, microcephaly, mental retardation, hirsuitism, and tapering fingers support the theory, suggested by others, of variable phenotypic expression of ring chromosomes.
Abstract: Ring chromosome abnormalities are rare in comparison with other cytogenetic anomalies. They have been described in all groups except group F, mainly in the D group and in the X chromosome. It has been proposed that patients with ring chromosome aberrations involving the same chromosome should have similar phenotypes, and attempts have been made to establish the existence of definite ring syndromes. We have studied a nine-year-old female patient who presented with coarse facial features, microcephaly, mental retardation, hirsuitism, and tapering fingers. Quinacrine-banded karyotypes derived from peripheral blood lymphocytes revealed a 46, XX, r(9) (p24→q34) pattern. Many of the facial and somatic features of our patients are distinctly different from those of other reported patients with ring-9, of which only five cases have been described. There is also little similarity to cases of 9p-, and we are unable to find reports of cases of 9q-. These studies support the theory, suggested by others, of variable phenotypic expression of ring chromosomes. In patients with ring chromosomes showing deletions at similar regions, phenotypic variability is the probable result of a combination of factors, including moaaicism (due to the tendency of ring chromosomes to missegregate during mitosis), variable ring structure (simple and polycentric rings, presumably containing duplications and deficiencies), and resulting instability of the ring chromosome.