Correlations of glutathione peroxidase activity with memory impairment in adults with Down syndrome.
BACKGROUND
Down syndrome (DS) is a genetic disorder (trisomy 21 in 96% of cases), associated with an excess of a key enzyme involved with free radical metabolism (FRM), superoxide dismutase-1 (SOD-1), that is encoded by a gene on chromosome 21. Consequently, SOD-1 activity is elevated in DS, which also occurs in conditions of oxidative stress, and is associated with a compensatory increase in glutathione peroxidase activity (GSHPx).


METHODS
This study examined the relationship of memory function with erythrocyte SOD-1, GSHPx and catalase (CAT) activity in 22-51 year old adults with DS.


RESULTS
Mean erythrocyte SOD-1 (p < .02) and GSHPx (p < .01), but not CAT (p = .76), activities were significantly greater in the DS group than the controls. In the DS group, erythrocyte GSHPx, but not SOD-1 or CAT activities, was significantly correlated with memory function (r = .625, p < .025, df = 13 for savings score, r = .631, p < .01, df = 14 for intrusion errors) but not with intelligence quotients.


CONCLUSIONS
These observations suggest a possible relationship between altered FRM with memory deficits among adults with DS within the age-range in that an age-related increase in the prevalence for Alzheimer's neuropathology is known to be robust before reaching a plateau of 100%.
Brugge
K
K
Department of Neuroscience, University of California, San Diego, USA.
Nichols
S
S
Saitoh
T
T
Trauner
D
D
D000328:Adult; D000367:Age Factors; D000544:Alzheimer Disease / Q000201:enzymology / Q000235:genetics / Q000523:psychology; D016022:Case-Control Studies; D002374:Catalase / Q000378:metabolism; D004314:Down Syndrome / Q000150:complications / Q000201:enzymology* / Q000523:psychology*; D004912:Erythrocytes / Q000201:enzymology; D005260:Female; D005609:Free Radicals / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism*; D006801:Humans; D007360:Intelligence; D008297:Male; D008568:Memory; D008875:Middle Aged; D009483:Neuropsychological Tests; D018709:Statistics, Nonparametric; D013482:Superoxide Dismutase / Q000378:metabolism*
D005609:Free Radicals; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase