Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: Gene-dosage effects in Down syndrome and trisomic mouse models. | Minireview Gene-dosage effects in Down syndrome and trisomic mouse models Katheleen Gardiner Address Eleanor Roosevelt Institute at the University of Denver Department of Biochemistry and Molecular Genetics University of Colorado Health Sciences Center 1899 Gaylord Street Denver CO 80206 USA. E-mail kgardine@ Published 30 September 2004 Genome Biology 2004 5 244 The electronic version of this article is the complete one and can be found online at http 2004 5 10 244 2004 BioMed Central Ltd Abstract The abnormalities found in human Down syndrome trisomy 21 have been thought to result from increased expression of genes on chromosome 21 because of their higher gene dosage. Now several groups have shown this to be generally the case but some inter-individual variability and other exceptions were found. The gene-dosage hypothesis for Down syndrome The Down syndrome trisomy 21 phenotype is characterized by abnormalities affecting most organs and organ systems 1 . Although the extent and severity of the abnormalities is highly variable among individuals all have some level of intellectual disability that is associated with specific brain regions and the performance of specific cognitive tasks 2 3 . The incidence of Down syndrome remains at approximately 1 in 800 live births and given the intellectual disabilities it is a significant social and medical issue. Although it has been known for several decades that Down syndrome is caused by an extra normal copy of the long arm of human chromosome 21 21q the molecular and cellular events linking the presence of an extra chromosome to the phenotypic features are unknown. The central hypothesis in Down-syndrome research is that gene dosage results in a 50 increase in expression of genes on chromosome 21q and that this directly or indirectly alters the timing pattern or extent of development. Accordingly an essential question in Downsyndrome research is are all trisomic genes overexpressed in all tissues and
