Down's Syndrome, Dementia, and Superoxide Dismutase

Mental handicap includes specific behavioural phenotypes apparently caused by single enzyme errors or deletions, for example, compulsive self-mutilation and hypoxanthine-guanine phosphoribosyl transferase deficiency in the Lesch-Nyham syndrome. In Down's syndrome, the possession of additional genetic material is found to be linked to various physical abnormalities (premature cataract formation and hypothyroidism). These close associations between types of behaviour, illnesses, and known genetic abnormalities offer promising avenues for research. In this article we concentrate on the well known link between Down's syndrome and presenile dementia.