Neurobiol Aging. 2011 Nov;32(11):2103-5. doi: 10.1016/j.neurobiolaging.2009.11.016. Epub 2009 Dec 21.
Effect of Coenzyme Q10 in mitigating oxidative DNA damage in Down syndrome patients, a double blind randomized controlled trial.

Down syndrome (DS) is a chromosomal abnormality (trisomy 21) associated with a complex phenotype. Oxidative stress is known to play a major role in this pathology both due to genetic and epigenetic factors, suggesting that oxidative imbalance contributes to the clinical manifestation of DS. In particular, the implications of oxidative DNA damage in Down syndrome has been linked with neurodegeneration. Here we report the results of a double blind controlled trial aimed at investigating the protective effect of Coenzyme Q(10) on DNA oxidation in this clinical setting using the single cell gel electrophoresis technique.

PMID: 20022408 
[INTERPRETATION:  The symptoms of Down Syndrome come out largely because of oxidative stress (cell damage by free radicals).  Oxidative stress damages the DNA and causes nerve cells to be progressively destroyed.]   There are foods, supplements, and drugs proven to reduce oxidative stress.