Ring chromosomes are rare chromosomal disorders that usually appear to occur de novo. A ring chromosome forms when due to deletion both ends of chromosome fuse with each other. Depending on the amount of chromosomal deletion, the clinical manifestations may be different. So, ring 18 syndrome is characterized by severe mental growth retardation as well as microcephaly, brain and ocular malformat...

habit and pollen morphology were studied in four taxa belonging to astragalus sect. macrophyllium in iran. data obtained from pollen morphology support the phenetic grouping based on habit morphology. in addition, meiotic chromosome number and behavior were analyzed in two species of the section. the species were cytogenetically analyzed and found to be tetraploid and possess a 2n = 4x = 32 chr...

a cytogenetic study was performed on 11 tetraploid cotton cultivars (gossypium hirsutum l.)including the oltan cultivar and its crossing progenies. the chromosome pairing and chiasma frequency, aswell as meiotic abnormalities were compared among the genotypes studied. heterozygote translocations withalternate orientation were observed between some of the chromosomes of the a genome and those of...

Cytogenetic studies of 91 consecutive patients with therapy-related myelodysplasia or overt acute nonlymphocytic leukemia disclosed characteristic defects of chromosome 7 in 48 cases and of chromosome 5 in 21 cases. The chromosome 5 abnormalities were consistently present in all abnormal mitoses at the time of diagnosis, as were the chromosome 7 abnormalities in 45 of the 48 patients. Various a...

Individuals affected by the classic chromosome deletion syndromes which were first identified at the beginning of the genetic age, are now positioned to benefit from genomic advances. This issue highlights five of these conditions (4p-, 5p-, 11q-, 18p-, and 18q-). It focuses on the increased in understanding of the molecular underpinnings and envisions how these can be transformed into effectiv...

| Genetic instability, which includes both numerical and structural chromosomal abnormalities, is a hallmark of cancer. Whereas the structural chromosome rearrangements have received substantial attention, the role of whole-chromosome aneuploidy in cancer is much less well-understood. Here we review recent progress in understanding the roles of whole-chromosome aneuploidy in cancer, including t...

Objective: To investigate antenatal detection the chromosome abnormalities in high risk pregnancies and correlation between karyotype analysis and FISH (Fluorescent In Situ Hybridization). Method: Were analyzed cytogenetic results from a total of 594 cases between 2008-2009. Amniotic fluid karyotyping and FISH have been offered to pregnant women with genetic risk, using the standard method and ...

Many human genetic disorders result from unbalanced chromosome abnormalities, in which there is a net gain or loss of genetic material. Such imbalances often disrupt large numbers of dosage-sensitive, developmentally important genes and result in specific and complex phenotypes. Alternately, some chromosomal syndromes may be caused by a deletion or duplication of a single gene with pleiotropic ...

G-banded chromosomes were studied from involved lymph nodes or other tumor masses in 94 patients with malignant lymphoma. Clonal chromosome abnormalities were identified in 91 patients including all 81 B-lymphomas but only 6 of 9 Tlymphomas. Many recurring chromosome abnormalities were found. Most common numerical alterations involved gains of chromosomes 12 (19% of patients), 18 (13%), 7 (12%)...