Search results for "Ring Chromosome"
showing 7 items of 7 documents
Single-Nucleotide Polymorphism Array-Based Characterization of Ring Chromosome 18
2012
Objective To study genotype–phenotype correlation of ring chromosome 18 [r(18)] in 9 patients with 46,XN karyotype. Study design In 9 patients with a de novo 46,XN,r(18) karyotype (7 females, 2 males), we performed high-resolution single-nucleotide polymorphism array analysis (Illumina Human Omni1-QuadV1 array in 6 patients, Affymetrix 6.0 array in 3 patients), investigation of parental origin, and genotype–phenotype correlation. Results No breakpoint was recurrent. Single metaphases with loss of the ring, double rings, or secondarily rearranged rings were found in some cases, but true mosaicism was present in none of these cases. In 3 patients, additional duplications in 18p (of 1.4 Mb, 2 …
Familial ring (18) mosaicism in a 23-year-old young adult with 46,XY,r(18) (::p11→q21::)/46,XY karyotype, intellectual disability, motor retardation …
2010
We report on a 23-year-old man with craniofacial findings of the holoprosencephaly spectrum disorder (microcephaly, hypotelorism, depressed nasal bridge, single median maxillary central incisor), fusion of C2-C3 vertebrae, intellectual disability, and severe sleep apnea. Chromosome analysis of blood lymphocytes showed 75% ring (18) cells and 25% normal cells, karyotype mos 46,XY,r(18)(::p11→q21::)[75]/46,XY[25]. His mother was phenotypically normal except for a double ureter and bifid renal pelvis as in his son. She had a supernumerary ring (18) in 10% of blood lymphocytes, karyotype mos 47,XX,+r(18)(::p11→q21::)[10]/46,XX[90]. Familial ring (18) is a rare cytogenetic abnormality. This is t…
Complex rearrangement of chromosomes 6 and 11 as the sole anomaly in atypical teratoid/rhabdoid tumors of the central nervous system.
2000
Atypical teratoid/rhabdoid tumor of the central nervous system is a rare childhood tumor with a distinct histologic appearance and an aggressive clinical course. Few tumors have been analyzed cytogenetically. The only consistent chromosomal abnormality identified in some of these tumors has been monosomy or deletions of chromosome 22; in others, a normal chromosome 22 was present. The authors report an atypical teratoid/rhabdoid neoplasm of the central nervous system with a novel complex rearrangement affecting chromosomes 6 and 11 as the sole anomaly. The involvement of region 11p15 could be important in the pathogenesis of this entity.
FISH of supernumerary marker chromosomes (SMCs) identifies six diagnostically relevant intervals on chromosome 22q and a novel type of bisatellited S…
2005
Supernumerary marker chromosomes (SMCs) are frequently found at pre- and postnatal cytogenetic diagnosis and require identification. A disproportionally large subset of SMCs is derived from the human chromosome 22 and confers tri- or tetrasomy for the cat eye chromosomal region (CECR, the proximal 2 Mb of chromosome 22q) and/or other segments of 22q. Using fluorescence in situ hybridization (FISH) and 15 different DNA probes, we studied nine unrelated patients with an SMC(22) that contained the CECR. Five patients showed the small (type I) cat eye syndrome (CES) chromosome and each one had the larger (type II) CES chromosome, small ring chromosome 22, der(22)t(11;22) extrachromosome, and a …
Karyotype analysis and marker chromosomes of renal cell carcinoma.
1988
Karyotyping was performed in 46 human renal cell carcinomas of various histological grades. Controls included chromosome analysis of normal renal parenchymal cells from the same patients. Various numerical chromosome aberrations were found as well as marker chromosomes. They are specific of the individual tumor but no single marker was identified occurring in all tumors tested. Only trisomy 3 was found in different tumors (31%), suggesting a more general character of this aberration. Histological dedifferentiation and large tumor size correlate with focusing of the karyotype towards distinct chromosomal modes indicative of distinct tumor cell subclones within these tumors. Their rapid growt…
Pigmentary mosaicism in hypomelanosis of Ito
1998
We report on a female with mental and motor retardation, facial dysmorphism, abnormal pigmentation reminiscent to hypomelanosis of Ito (HI), and karyotypic mosaicism involving a small supernumerary marker chromosome. The marker chromosome was defined by fluorescence in situ hybridisation (FISH) as a ring X chromosome with breakpoints in the juxtacentromeric region. FISH analysis showed that the ring does not include the XIST locus at the X-inactivation centre and, therefore, may not be subject to X inactivation. X-inactivation studies with the HUMARA (human androgen receptor) and FMR1 assay showed a skewed X-inactivation pattern (85:15) with preferential inactivation of the paternal X chrom…
Ring 17 syndrome: first clinical report without intellectual disability
2015
Ring chromosomes are rare abnormalities caused by the fusion of the telomeric regions. Three-ring chromosome syndromes (Cr 20, Cr 17 and Cr 14) cause epilepsy with variable phenotypes. In ring 17 patients with mild phenotype, some authors have shown an epilepsy syndrome similar to that of ring 20. We report the first case of a girl with ring chromosome 17 and a normal neurological and general cognitive profile. She had had, from 9 years old, focal pharmacoresistant epilepsy associated with episodes of non-convulsive status epilepticus with mainly autonomic features. Cytogenetic analysis revealed an abnormal karyotype characterised by the presence of de novo ring chromosome 17 in 19% of meta…