Researchers know that Down syndrome is caused by an extra chromosome.....
Extra chromosomes.. is the cause of DS?
More than 40 yeras of research still waiting....
Hi,
There are a few articles relevant to this topic:
Antonarakis SE, Skotko BG, Rafii MS, Strydom A, Pape SE, Bianchi DW, Sherman SL, Reeves RH. Down syndrome. Nat Rev Dis Primers. 2020 Feb 6;6(1):9. doi: 10.1038/s41572-019-0143-7
Alexandrov PN, Percy ME, Lukiw WJ. Chromosome 21-Encoded microRNAs (mRNAs): Impact on Down's Syndrome and Trisomy-21 Linked Disease. Cell Mol Neurobiol. 2018 Apr;38(3):769-774. doi: 10.1007/s10571-017-0514-0
Zhao Y, Jaber V, Percy ME, Lukiw WJ. A microRNA cluster (let-7c, miRNA-99a, miRNA-125b, miRNA-155 and miRNA-802) encoded at chr21q21.1-chr21q21.3 and the phenotypic diversity of Down's syndrome (DS; trisomy 21). J Nat Sci. 2017 Sep;3(9):e446
Brás A, Rodrigues AS, Gomes B, Rueff J. Down syndrome and microRNAs. Biomed Rep. 2018 Jan;8(1):11-16. doi: 10.3892/br.2017.1019
Patterson D. Molecular genetic analysis of Down syndrome. Hum Genet. 2009 Jul;126(1):195-214. doi: 10.1007/s00439-009-0696-8
Dear Anand,
Thanks for the ref but i think they discuss the same think.
"Mouse models of DS, involving trisomy of all or part of human chromosome 21 or orthologous mouse genomic regions, are providing valuable insights into the contribution of triplicated genes or groups of genes to the many clinical manifestations in DS. This endeavour is challenging, as there are >200 protein-coding genes on chromosome 21 and they can have direct and indirect effects on homeostasis in cells, tissues, organs and systems. Although this complexity poses formidable challenges to understanding the underlying molecular basis for each of the many clinical features of DS, it also provides opportunities for improving understanding of genetic mechanisms underlying the development and function of many cell types, tissues, organs and systems. Since the first description of trisomy 21, we have learned much about intellectual disability and genetic risk factors for congenital heart disease. The lower occurrence of solid tumours in individuals with DS supports the identification of chromosome 21 genes that protect against cancer when overexpressed."
All the disussions is around the triplicata story of genes... and their consequences...Might be another explanation..model. Why numbers to be always the justification of our conceptions...
PS. When the system positions the same conception (People) at the top positions then the whole system is under question. See Cancer see virus... the globe is directed by 10 PharmaCo and 10 Big Scientists that very likely are wrong...
Hi,
Such type of variation in phenotypes (clinical, intermediate, and endophenotypes) is more evident in cases of Autism spectrum disorder.
How much evidence is there contrary to the opinion which is presently thought of?
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