Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
2007-6-4
pubmed:abstractText
Down syndrome (DS) is a chromosomal disorder whereby genes on chromosome 21 are present in three copies. This gene copy imbalance is thought to be responsible for a number of debilitating conditions experienced by individuals with DS. Amongst these is a reduced cerebellar volume, or cerebellar hypoplasia, which is believed to contribute to the perturbation of fine motor control. Mouse models of DS (such as Ts65Dn, Ts1Cje, Tc1) exhibit a cerebellar phenotype similar to that of individuals with DS and which primarily manifests as a disruption of the density of the granule cell layer. Dissecting which of the three-copy genes are responsible for this phenotype (the primary gene dosage effect) has been a task undertaken by researchers working with various segmental trisomies and transgenic mice. It is generally agreed that, when expressed, three-copy genes of trisomic mice are expressed at around 1.5 times that of the same genes in euploid (wild-type) mice. However, amongst these studies there does not appear to be a consensus on the nature and extent of differential expression of two-copy genes in trisomic mice-the secondary dosage effect. Much of this variation may have to do with the stage of development investigated and the nature and complexity of the tissue (i.e. whole brain versus the cerebellum). The recent discovery that trisomic granule cell precursors are less sensitive to sonic hedgehog-induced proliferation has opened up another avenue for the identification of three-copy genes responsible for the cerebellar phenotype. It is hoped that further investigation of this phenomenon, together with new mouse segmental trisomies and transgenics, will reveal the cause of the proliferation deficit and allow for potential treatment.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0301-0082
pubmed:author
pubmed:issnType
Print
pubmed:volume
82
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
87-94
pubmed:meshHeading
pubmed:year
2007
pubmed:articleTitle
Down syndrome gene dosage imbalance on cerebellum development.
pubmed:affiliation
Laboratoire de Neurobiologie, UMR 7637, ESPCI, Paris, France. r.moldrich@uq.edu.au
pubmed:publicationType
Journal Article, Review, Research Support, Non-U.S. Gov't