[The pathogenesis of mental retardation in trisomy 21]

An adequate number of nerve cells, their connection by dendrites and axons, the transmission of information by chemical mediators are all necessary for normal brain function. Monocarbonic acid residues, purines and pyrimidines and tubulins and biopterin are essential to ensure that the necessary chemical processes can take place. In trisomy 21 the metabolism is disturbed by the enhancement of individual enzyme activities. Particular clinical effects suggest specific therapeutic interventions. The effects can be influenced by way of the monocarbonic acid metabolisms. The action of thyroxine is especially interesting, as it inhibits the disintegration of monocarbonic acids.