Showing papers on "Ring chromosome published in 1997"
TL;DR: Findings indicate that specific chromosomal bands and/or regions are nonrandomly involved in osteosarcoma and may provide useful clinical information.
164 citations
TL;DR: It is proposed that epilepsy associated with ring chromosome 20 constitutes a new syndrome that may provide an opportunity to scrutinize a genetic mechanism of epilepsy.
Abstract: Six cases of epilepsy associated with ring chromosome 20 are presented. The study of these cases and 20 cases reported in the literature revealed that they constitute a distinct epileptic syndrome: frequent seizures consisting of a prolonged confusional state, with or without additional motor seizures, and an ictal EEG pattern of long-lasting bilateral paroxysmal high-voltage slow waves with occasional spikes. Neurological examination results were normal, and neuroimaging studies often failed to disclose a brain lesion. The seizures were resistant to antiepileptic drug therapy. Comparison of the electroclinical features of nonconvulsive status epilepticus in six patients with and four patients without ring chromosome 20 revealed that the group with the chromosomal anomaly had more frequent, comparatively brief episodes of confusion associated with a less prominent spike component on the EEG. We propose that epilepsy associated with ring chromosome 20 constitutes a new syndrome that may provide an opportunity to scrutinize a genetic mechanism of epilepsy.
145 citations
TL;DR: The findings suggest that patients who need microinsemination should undergo chromosome analysis and should counsel patients about obtaining adequate information on each chromosome abnormality.
Abstract: The aim of this study was to investigate the influence of a chromosome abnormality on male infertility. The subjects consisted of 1,007 males with the chief complaint of infertility. Karyotyping was conducted mainly by G banding. Major chromosome abnormalities were observed in 62 patients (6.2%) in total and consisted of sex chromosome abnormalities were observed in 62 patients (6.2%) in total and consisted of sex chromosome abnormalities in 38 patients (3.8%) and autosomal chromosome abnormalities in 24 (2.4%). Among the patients with sex chromosome abnormalities, 28 cases were 47, XXY, 3 were 47,XYY, and 7 cases had a Y chromosome abnormality. Autosomal chromosome abnormalities comprised 10 cases of reciprocal translocation, 8 cases of Robertsonian translocation, 5 cases of inversion, and 1 case of ring chromosome. In patients with a sperm density or = 30.1 mIU/ml, a luteinizing hormone value > or = 8.9 mIU/ml, a testosterone value < or = 2.69 ng/ml, or an average testis volume < or = 8 ml, the incidence of major chromosome abnormalities was significantly higher. These findings suggest that patients who need microinsemination should undergo chromosome analysis. We should counsel patients about obtaining adequate information on each chromosome abnormality.
105 citations
TL;DR: Results of FISH and RT-PCR experiments indicate a large deletion of the X chromosome consistent with a small-ring X chromosome with approximate breakpoints near p11.2 and q13, comparable to the observation of others where an atypically severe phenotype has been associated with the presence of an r(X), or small mar(X).
Abstract: A female patient with the karyotype 45,X/46, X, r(X)(p11.2 q13) and severe developmental delay, prominent fingertip pads, long palpebral fissures, short stature, and history of hypotonia had a phenotype reminiscent of Kabuki syndrome. We hypothesized that overexpression of X chromosome-derived sequences might be associated with the Kabuki-like phenotype observed. The nature and parental origin of this small-ring X were ascertained using a combination of genotyping with microsatellite markers and quantitative Southern blotting. PCR-based genotyping demonstrated heterozygosity at X-linked loci SBMA (Xq11-q12) and DXS227 (Xq13.1). Hemizygosity was observed at several loci: DMD STR-49 (Xp21.2), DXS1003 (Xp11.23), DXS988 (Xp11.21), DXS101 (Xq21.3), FMR-1 (Xq27.3), and DXYS64 (Xq28). This ring X chromosome is paternally derived since only maternal alleles are inherited at three informative microsatellite loci. Results of FISH and RT-PCR experiments indicate that the XIST locus is missing in the ring X chromosome and not expressed. These data indicated a large deletion of the X chromosome consistent with a small-ring X chromosome with approximate breakpoints near p11.2 and q13. These results are comparable to the observation of others where an atypically severe phenotype has been associated with the presence of an r(X), or small mar(X).
53 citations
TL;DR: The FISH analysis using painting probes not only confirmed the cytogenetic results but also allowed the identification of tumor-specific chromosome changes in those cases presenting low mitotic index or with poor quality chromosomes.
38 citations
TL;DR: Interestingly, unlike ring chromosome 14, the 14q32.3 terminal deletion has rarely been reported, possibly because it is harder to detect, and an optimal chromosome preparation is required for its identification.
Abstract: A patient with a 14q32.3 terminal band deletion and cat cry is reported. Review of four other 14q32.3 deletion cases suggests the possible presence of a recognisable 14q32.3 terminal deletion syndrome, which is characterised by (1) apparently postnatal onset of small head size in comparison to body size, (2) high forehead with lateral hypertrichosis, (3) epicanthic folds, (4) broad nasal bridge, (5) high arched palate, (6) single palmar crease, and (7) mild to moderate developmental delay. Although none of the above seven features in unique to this syndrome, and indeed are quite common in other chromosomal disorders or genetic syndromes, patients with a terminal 14q32.3 deletion do show a recognisable facial gestalt. Interestingly, unlike ring chromosome 14, the 14q32.3 terminal deletion has rarely been reported, possibly because it is harder to detect, and an optimal chromosome preparation is required for its identification.
34 citations
TL;DR: It is suggested that women with karyotypically abnormal fibroadenomas may have an increased risk of developing subsequent breast cancer, and different chromosome anomalies might have different pathogenetic and/or prognostic significance.
Abstract: Short-term cultures of 50 fibroadenomas of the breast were cytogenetically analyzed. Nine tumors were found to display clonal chromosome aberrations. One had multiple, cytogenetically unrelated clones, whereas the others had a single abnormal clone each. Four cases had one balanced translocation as the sole anomaly, and one had a complex intrachromosomal rearrangement of chromosome 3, leading to loss of 3p material. One fibroadenoma had a single numerical aberration, and one had supernumerary ring chromosomes. The remaining 2 cases had both numerical and structural aberrations. The only recurrent alterations were trisomy 20 and rearrangement of chromosome arm 1p. The finding of similar chromosomal aberrations in fibroadenomas and carcinomas suggests that women with karyotypically abnormal fibroadenomas may have an increased risk of developing subsequent breast cancer. If so, different chromosome anomalies might have different pathogenetic and/or prognostic significance. Int. J. Cancer, 70:282–286, 1997. © 1997 Wiley-Liss, Inc.
32 citations
TL;DR: The patient illustrates the need to consider cytogenetic studies in patients with the Seckel phenotype, so that accurate diagnoses can be given to families, and suggests that there may be a locus for oligomeganephronia distal to the Wolf-Hirschhorn critical region on 4p.
Abstract: We present a patient with features suggestive of Seckel syndrome who was found to be mosaic for ring 4 chromosome. Seckel syndrome is a rare entity characterized by marked growth retardation, microcephaly, facies characterized by receding forehead and chin, large beaked nose, and severe retardation, usually thought to be inherited as an autosomal recessive condition. In addition, our patient had oligomeganephronia, a rare and usually sporadic renal malformation, previously reported in two other patients with abnormalities of chromosome 4. Besides pointing out the overlap between the Seckel phenotype and Wolf-Hirschhorn syndrome, our patient illustrates the need to consider cytogenetic studies in patients with the Seckel phenotype, so that accurate diagnoses can be given to families. Also, the case suggests that there may be a locus for oligomeganephronia distal to the Wolf-Hirschhorn critical region on 4p.
26 citations
TL;DR: A newborn female infant presented with abnormalities of the external genitalia including a 3 x 1 cm phallic structure, a perineal urethral opening, bifid scrotum, and a single urogenital opening, however, there were no signs of Ullrich-Turner syndrome.
Abstract: A newborn female infant presented with abnormalities of the external genitalia including a 3 x 1 cm phallic structure, a perineal urethral opening, bifid scrotum, and a single urogenital opening. Peripheral blood karyotype was 45,X[81]/46,X,+r(Y)[19], however, there were no signs of Ullrich-Turner syndrome. High resolution G-banding as well as C- and Q-banding did not demonstrate any specific banding pattern or presence of heterochromatin on the ring. However, it was noticed that some of the rings were larger than others. FISH with a probe for Yq12 was negative in all metaphases studied. A Y-specific paint probe hybridized to the entire ring chromosome, confirming its origin. PCR analysis showed the presence of the SRY locus and of proximal Yq locus DYS271. Triple color FISH with probes for the Y centromere, DYZ5 (Yp), and all human telomeres showed the existence of different types of rings, some dicentric, some tetracentric, and some probably octacentric. Owing to the increased risk for gonadoblastoma, a surgical removal of the gonads was performed.
23 citations
TL;DR: A patient with a multiple congenital abnormalities/mental retardation (MCA/MR) syndrome including facial abnormalities, agenesis of the corpus callosum, heart defect, 1st ray anomalies of the upper limb, and ambiguous genitalia, whose phenotype overlaps a previous description of XK syndrome is reported.
Abstract: We report on a patient with a multiple congenital abnormalities/mental retardation (MCA/MR) syndrome including facial abnormalities, agenesis of the corpus callosum, heart defect, 1st ray anomalies of the upper limb, and ambiguous genitalia, whose phenotype overlaps a previous description of XK syndrome The patient has a ring chromosome (13) with deletion 13q32-qter Molecular analysis demonstrated loss of the region from D13S317 to D13S285 and a paternal origin of the anomaly
20 citations
TL;DR: The findings suggest that the ring chromosomes were formed during meiosis, perhaps involving complex rearrangements, resulting in a germ cell containing all markers, with subsequent loss of markers during cell division.
Abstract: Multiple supernumerary ring chromosomes are a rare cytogenetic finding which is poorly understood. With the introduction of FISH techniques, their chromosomal origin can now be defined clearly. The techniques described previously are complicated and time consuming. We report a new rapid technique which has been used to investigate two new cases. Multiple probes were hybridised to a single slide by means of marking the underside with a diamond pen to form a grid of squares, pipetting fixed cell suspension into the centre of each square, forming a rubber solution grid on the denatured, dehydrated slide following the lines on the underside, adding a mixture of probes into each square, and sealing the slide with a silicone rubber rim and a covering slide. The type of probe and the size, dimensions, and number of squares in the grid can be tailored to individual cases. The two new cases examined here are mosaic for three (case 1) and four (case 2) supernumerary ring chromosomes derived from different chromosomes. Normal cell lines were also present. The karyotypes were established as 47,XY,+r(4)/47,XY,+r(17)/.../48,XY,+r(17),+r(20)/ 49,XY,+r(4),+r(17),+r(20)/46,XY for case 1 and 47,XX,+r(4)/47,XX,+r(8)/47,XX,+r (10)/48,XX,+r(X),+r(4)/... /49,XX,+r(X),+r (8),+r(10)/46,XX for case 2. Our findings suggest that the ring chromosomes were formed during meiosis, perhaps involving complex rearrangements, resulting in a germ cell containing all markers, with subsequent loss of markers during cell division. Our second case also shows that the outcome is not invariably mental or physical handicap.
TL;DR: FISH studies confirmed that the ring chromosome is X-derived and demonstrated that it lacks the XIST locus, and the spectrum of phenotypes associated with monosomy X and small ring X chromosomes are discussed.
Abstract: Ring X chromosomes that lack the X inactivation center and fail to be inactivated have been implicated as a cause of mental retardation and multiple congenital anomalies. We report on a stillborn fetus with karyotype mos45,X/46,X,r(X) and early urethral obstruction or prune-belly sequence, single umbilical artery, limb deficiency, horseshoe kidney, cardiac hypertrophy, persistent left superior vena cava, and axial skeleton abnormalities. Fluorescent in situ hydridization (FISH) studies confirmed that the ring chromosome is X-derived and demonstrated that it lacks the XIST locus. The findings in this fetus are discussed with regard to the spectrum of phenotypes associated with monosomy X and small ring X chromosomes.
TL;DR: A constitutional G to A transition in the proximal 3′ untranslated region of isoforms 1 and 2 was identified in the patient’s NF2 gene and shown not to affect differential splicing or mRNA stability.
Abstract: The case of a seriously disabled and retarded female patient with neurofibromatosis type 2 (NF2) is reported. She suffered from bilateral vestibular schwannomas, multiple intracranial meningiomas and neurinomas. The constitutional karyotype of the patient was 46,XX, r(22)/45,XX,–22. A constitutional G to A transition in the proximal 3′ untranslated region of isoforms 1 and 2 was identified in the patient’s NF2 gene and shown not to affect differential splicing or mRNA stability. The instability of the ring chromosome 22 with the associated loss of tumor suppressor genes on chromosome 22, in particular the loss of the NF2 gene, are assumed to have caused multiple tumorigenesis in this patient
TL;DR: Small supernumerary marker chromosomes of 3 patients were characterized at the molecular cytogenetic level and two ring chromosomes and one metacentric marker were shown to be distamycinA/DAPI-negative and did not possess satellite regions after conventional banding techniques.
Abstract: Small supernumerary marker chromosomes of 3 patients were characterized at the molecular cytogenetic level. Two ring chromosomes and one metacentric marker were shown to be distamycinA/DAPI-negative and did not possess satellite regions after conventional banding techniques. Fluorescence in situ hybridization (FISH) was performed and in all 3 cases the supernumerary markers were shown to be derived from chromosome 20. Phenotypes are described and discussed with respect to karyotypes. Two of the patients are developmentally and/or phenotypically normal. The first patient has a ring chromosome, containing a small amount of euchromatic material; the second patient is the carrier of a small, metacentric and most probably heterochromatic marker. Patient 3 has physical anomalies, including a congenital heart defect and delayed motor development, but is intellectually almost normal. His marker chromosome is a ring containing a small amount of euchromatic material.
TL;DR: A four year old Caucasian girl with a constitutional ring chromosome 22 abnormality and developmental delay presented with increasing ataxia and a six week history of non‐specific symptoms and Imaging studies demonstrated a large third ventricular tumor with apparent involvement of the septum.
Abstract: Case Abstract
A four year old Caucasian girl with a constitutional ring chromosome 22 abnormality and developmental delay presented with increasing ataxia and a six week history of non-specific symptoms. Imaging studies demonstrated a large third ventricular tumor with apparent involvement of the septum. Microscopic and immunohistochemical studies demonstrated an atypical teratoid/rhabdoid tumor. This tumor is compared and contrasted to peripheral malignant rhabdoid tumors and central primitive neuroectodermal tumors. The role of a putative tumor suppressor gene on the long arm of chromosome 22 in the pathogenesis of these tumors is also discussed.
TL;DR: These are the only PWS patients reported with a supernumerary marker chromosome other than inv dup(15) characterized by FISH, and it is demonstrated that the small markers in the deleted and UPD patient originated from chromosome 15 and X.
Abstract: A small supernumerary chromosome was observed in two Prader-Willi syndrome (PWS) patients. The clinical diagnosis of PWS was confirmed by the ascertainment of the deletion of region 15q11-13 in one case and uniparental disomy (UPD) of the same region in the other. The markers were negative for dystamycinA/DAPI banding, did not contain NOR-positive satellites, and had an appearance consistent with a very small ring chromosome. Fluorescent in situ hybridization (FISH) analysis with the “all human centromere” probe indicated the presence of centromeric sequences in both markers. Chromosomal in situ suppression hybridization with chromosome specific libraries demonstrated that the small markers in the deleted and UPD patient originated from chromosome 15 and X, respectively. To the best of our knowledge these are the only PWS patients reported with a supernumerary marker chromosome other than inv dup(15) characterized by FISH. Am. J. Med. Genet. 68:99–104, 1997 © 1997 Wiley-Liss, Inc.
TL;DR: Based on the phenotype and the laboratory findings, the prognosis given to the patient was for short stature and azoospermia without an increased risk for gonadoblastomas.
Abstract: A newborn male infant presented with midshaft hypospadias, chordee, and undescended left testis. Both gonads lacked the tunica albuginea and appeared to be adjacent to structures resembling fallopian tubes. On biopsy, there was marked dysgenesis of both gonads, with a paucity of testicular tubules and foci of ovarian-like stroma. Peripheral blood karyotype was 46,X,mar(Y) [39]/45,X [5]. Right gonadal biopsy material showed the same mosaicism but with a higher proportion of 45,X cells (46%). PCR and FISH analyses with primers/probes from different Yp, Yq, and Ycen loci defined the structure of the marker Y as a probable complex ring with breakpoints in Yq11.21 (very close to the centromere) and in Yp11.32 (the pseudoautosomal region). Based on the phenotype and the laboratory findings, the prognosis given to the patient was for short stature and azoospermia without an increased risk for gonadoblastomas.
TL;DR: It is indicated that a hemizygous state for the myelin protein gene may be related to the abnormal myelination in a Japanese boy with ring chromosome 18 in whom abnormalMyelination was observed on magnetic resonance imaging.
Abstract: We describe a Japanese boy with ring chromosome 18 in whom abnormal myelination was observed on magnetic resonance imaging. Cytogenetic investigation revealed 46, XY, r(18) (p11.2 q21.33). T 2- weighted magnetic resonance imaging scan of the brain demonstrated high signal intensity consistent with abnormal myelination. Microsatellite marker analysis of DNA demonstrated only one copy of the myelin basic protein gene, derived from the mother. The present case indicates that a hemizygous state for the myelin protein gene may be related to the abnormal myelination.
TL;DR: The ring X chromosome of the mother was most likely transmitted to the newborn, and an ovum with the ring X chromosomes can be fertile and can produce a viable zygote.
TL;DR: Karyotype analysis appears warranted in cases of anencephaly with holoprosencephalic facies and ring chromosome 18 [r(18)] is reported, the first instance of an accompanying karyotypic abnormality.
Abstract: An anencephalic infant with holoprosencephalic facies and ring chromosome 18 [r(18)] is reported with review of the pertinent literature. Although the association of anencephaly and holoprosencephalic facies is well established, this is the first instance of an accompanying karyotypic abnormality. Review of other r(18) cases suggests that this is not a coincidental finding. Karyotype analysis appears warranted in cases of anencephaly with holoprosencephalic facies.
TL;DR: A 3-year-old-girl with mosaic partial trisomy 17 due to an additional ring chromosome 17 in 13% of cells analysed showed mild developmental delay with subtle facial and other minor abnormalities including single palmar creases, generalised joint laxity, and a scoliosis.
Abstract: We report on a 3-year-old-girl with mosaic partial trisomy 17 due to an additional ring chromosome 17 in 13% of cells analysed. This was identified by fluorescence in situ hybridisation (FISH) using a whole chromosome 17 specific paint as well as probes specific for the Smith-Magenis and Miller-Dieker regions of chromosome 17p. This girl showed mild developmental delay with subtle facial and other minor abnormalities including single palmar creases, generalised joint laxity, and a scoliosis.
TL;DR: An 8 year old boy with ring chromosome 21 who was susceptible to sinorespiratory infections due to hypogammaglobulinaemia is reported, and regular replacement of intravenous gammag lobulin effectively reduced such infectious episodes.
Abstract: An 8 year old boy with ring chromosome 21 who was susceptible to sinorespiratory infections due to hypogammaglobulinaemia is reported. He presented with the characteristic features of monosomy 21 syndrome, such as psychomotor retardation, hypertonia, large saccular ears, prominent nasal bridge, micrognathia, thrombocytopenia, and patent ductus arteriosus. His serum IgG concentration was less than 1.5 g/l at 3 years and 6 months of age after repeated hospitalisations with pneumonia, otitis media, and convulsions. Regular replacement of intravenous gammaglobulin effectively reduced such infectious episodes. A predisposition to infection in patients with ring chromosome 21 may be explained by hypogammaglobulinaemia and merit treatment with gammaglobulin.
TL;DR: It is concluded that all nonlabeled chromosomes have the same probability of participating in reciprocal translocation with the labeled chromosome, 1R, and that most induced reciprocal translocations involved exchanges of chromosome segments of approximately equal length.
Abstract: To obtain translocations involving specific chromosomes in rye, a line in which chromosome 1R has large C-bands on its two telomeres but which lacks C-bands (or has very small ones) on the telomeres of the remaining chromosomes was used. About 6% of the plants produced using pollen from irradiated (1.2 krad (1 rad = 10 mGy)) spikes of this line possessed structural changes involving the labeled chromosome. These aberrations included translocations, ring chromosomes, isochromosomes, and telocentrics. It is concluded (i) that all nonlabeled chromosomes have the same probability of participating in reciprocal translocations with the labeled chromosome, 1R, and (ii) that most induced reciprocal translocations involved exchanges of chromosome segments of approximately equal length. The use of lines having the appropriate combination of telomeric C-bands improves the efficiency of obtaining reciprocal translocations involving specific chromosomes that could be used in the construction of detailed physical maps....
TL;DR: The hypothesis that the polarity of rejoining sites is either conserved or inverted and that illegitimate rejoinings are partially repaired could explain the results.
Abstract: DNA polarity at sister chromatid exchange (SCE) sites were studied in ring chromosomes from Chinese hamster cells. If the polarity of DNA strands was conserved, a double-length, symmetric dicentric ring chromosome with symmetric twin SCEs appeared after two cell cycles when a SCE occurred in S 1 . Indeed, approximately two-thirds of double-length, symmetric ring chromosomes belonged to this class. One-third of them, however, did not show symmetric SCEs, suggesting that polarity was not always conserved. SCE counts at centromeric regions were not high enough to account the frequency (about 1/3) of apparently inverted rejoining sites. The hypothesis that the polarity of rejoining sites is either conserved or inverted and that illegitimate rejoinings are partially repaired could explain the results. Telomere-like structures or intermediate structures during double-strand repair processes may contribute to the inverted polarity.
TL;DR: A patient with multiple anomalies and severe developmental delay was diagnosed with a small supernumerary ring chromosome found in 40% of her lymphocyte cells at birth, which later was identified as deriving from chromosome 17.
Abstract: We present a patient with multiple anomalies and severe developmental delay. A small supernumerary ring chromosome was found in 40% of her lymphocyte cells at birth. The origin of the marker chromosome could not be determined by GTG banding, but fluorescent in situ hybridization (FISH) later identified the marker as deriving from chromosome 17.
Journal Article•
TL;DR: The results suggest a mechanism of ring formation, an end-to-end fusion after loss of the palindromic nucleotide sequences at the telomeres, and PRINS, a fast and sensitive method of detecting nucleic acid sequences in situ, may be a reliable technique for detecting chromosomal aneuploidies and some structural rearrangements.
28 Nov 1997
TL;DR: It is concluded that descriptions of mental retardation were often unqualified and at times ambiguous, and in contrast to the characteristic description of ring chromosome 13 syndrome which describes marked mentally retardation a small number of cases with mildmental retardation exist.
Abstract: A case of ring 13 syndrome inan18-year-old male is presentedwithparticularfocus on mental retardation.The clinical picture was characterized by mild mental retardation, microcephaly, large low set ears, a broad nasalbridge, epicanthus, micrognathiaand short pbiltrum. A review of the literature with a focus on mental retardation concluded that descriptions of mental retardation were often unqualified and at times ambiguous. Furthermore, in contrast to the characteristic description of ring chromosome 13 syndrome which describes marked mental retardation a small number of cases with mild mental retardation exist. EByword chromosomalabnormality, mentalretardaL6on,ring chromosome 13 syndrome.
TL;DR: Six cases of epilepsy and ring chromosome 20 are reported and 20 additional cases in the literature are reviewed from the National Epilepsy Center, Shizuoka Higashi Hospital, Japan.
Abstract: Six cases of epilepsy and ring chromosome 20 are reported and 20 additional cases in the literature are reviewed from the National Epilepsy Center, Shizuoka Higashi Hospital, Japan.