Topic
Chromosome 21
About: Chromosome 21 is a research topic. Over the lifetime, 4736 publications have been published within this topic receiving 206655 citations. The topic is also known as: chr21 & Homo sapiens chromosome 21.
Papers published on a yearly basis
Papers
More filters
TL;DR: The cloned DYRK gene, which contains a nuclear targeting signal sequence, a protein kinase domain, a putative leucine zipper motif, and a highly conserved 13-consecutive-histidine repeat, may be involved in the abnormal neurogenesis found in Down syndrome.
173 citations
TL;DR: DYRK1A protein was found to be present in every analyzed structure irrespective of age, suggesting an important, but diverse from developmental role played by this kinase in adult central nervous system and implying that overexpression of DYRK 1A in DS may be potentially relevant to MR status of these individuals during their entire life span.
173 citations
TL;DR: Probe St14 reveals one of the most polymorphic loci known to date in the human genome and should be of great use for the genetic study of three important diseases: hemophilia A, mental retardation with a fragile X chromosome, and adrenoleukodystrophy.
Abstract: A DNA fragment (named St14) derived from the human X chromosome reveals a small family of related sequences that have been mapped to the Xq26-Xq28 region by using a panel of rodent-human somatic cell hybrids. The probe detects in human DNA digested by Taq I a polymorphic system defined by a series of at least eight allelic fragments with a calculated heterozygosity in females of 80%. With Msp I, we found three additional restriction fragment length polymorphisms, each of them being defined by two alleles. These polymorphisms are also common in Caucasian populations. The genetic locus defined by probe St14 has been localized more precisely to the distal end of the X chromosome (in band q28) by linkage analysis to other polymorphic DNA markers. The results obtained suggest that the frequency of recombination is distributed very unevenly in the q27-qter region of the X chromosome, with a cluster of seven tightly linked loci in q28 showing about 30% recombination with the gene for coagulation factor IX located in the neighboring q27 band. Probe St14 reveals one of the most polymorphic loci known to date in the human genome, and 17 different genotypes have already been observed. It constitutes the best marker on the X chromosome and should be of great use for the genetic study of three important diseases: hemophilia A, mental retardation with a fragile X chromosome, and adrenoleukodystrophy.
172 citations
TL;DR: Examining the expression of chromosome 21-localized genes in myeloblasts from newly diagnosed AML patients found increased CBS transcripts could result in elevated CBS activity, which modulates ara-C metabolism by altering reduced folate pools, deoxycytidine triphosphates pools, S-adenosylmethionine levels, and/or methylation of the deoxy Cystathionine-beta-synthase gene.
171 citations
TL;DR: Analysis of maternal meiosis I errors indicates that a single telomeric exchange imposes the same risk for nondisjunction, irrespective of the age of the oocyte, and emphasizes the fact that human nondisJunction is a multifactorial trait that must be dissected into its component parts to identify specific associated risk factors.
Abstract: Nondisjunction of chromosome 21 is the leading cause of Down syndrome. Two risk factors for maternal nondisjunction of chromosome 21 are increased maternal age and altered recombination. In order to provide further insight on mechanisms underlying nondisjunction, we examined the association between these two well established risk factors for chromosome 21 nondisjunction. In our approach, short tandem repeat markers along chromosome 21 were genotyped in DNA collected from individuals with free trisomy 21 and their parents. This information was used to determine the origin of the nondisjunction error and the maternal recombination profile. We analyzed 615 maternal meiosis I and 253 maternal meiosis II cases stratified by maternal age. The examination of meiosis II errors, the first of its type, suggests that the presence of a single exchange within the pericentromeric region of 21q interacts with maternal age-related risk factors. This observation could be explained in two general ways: 1) a pericentromeric exchange initiates or exacerbates the susceptibility to maternal age risk factors or 2) a pericentromeric exchange protects the bivalent against age-related risk factors allowing proper segregation of homologues at meiosis I, but not segregation of sisters at meiosis II. In contrast, analysis of maternal meiosis I errors indicates that a single telomeric exchange imposes the same risk for nondisjunction, irrespective of the age of the oocyte. Our results emphasize the fact that human nondisjunction is a multifactorial trait that must be dissected into its component parts to identify specific associated risk factors.
170 citations