Scientists at the University of Geneva and ETHZ Zurich (Institute for Technology and Natural Sciences)"have discovered that the symptoms of Down syndrome are triggered by the uncontrolled deregulation of cell proteins". Their results have been published in the Nature Communications journal.
Down syndrome is the most common genetic disease. It is caused by the presence of an extra copy of chromosome 21. Until now, scientists have focused on analysing the DNA of individuals with Down syndrome. In this recent study, both teams "analysed the proteins of individuals with Down syndrome, for the first time". Findings showed that Down syndrome "also affects proteins coded by genes located in chromosomes other than" chromosome 21: "The cells are saturated with the excess protein generated by the triplicate genes and can no longer manage to regulate the quantity of proteins". Their work has also demonstrated that the mitochondria of individuals with Down syndrome are also affected since the proteins making up the mitochondria are "reduced excessively".
To analyse "only the protein variations due to the genetic anomaly and not those that can be attributed to individual differences", scientists studied the cells of twins with the same genetic heritage "except that one has Down syndrome and the other one doesn't". They then validated these results with other cohorts of Down syndrome patients.
Professor S.E. Antonarakis welcomes this progress: "For the first time, we have an exhaustive analysis of proteins that are deregulated by Down Syndrome. This may explain the various symptoms of Down syndrome (…). We now need to find which of the deregulated proteins are responsible for each symptom of Down syndrome and see if we can shed light on other types of cells such as neurones and cardiac cells severely affected by Down syndrome, etc."
Université de Genève (28/11/2017)