Types of enzymatic overdosing in trisomy 21: erythrocytic superoxide dismutase-AJ and phosphoglucomutase.

A comparative study was carried out on the hemolysates of 6 trisomic 21 and 6 normal subjects, by electrophoresis in starch gel, determining by a combined staining method both SOD-A (former IPO-dimer) and PGM activity. The enzymes were found statistically to be in a hyperactive status, the ratio of trisomic to normal values being approximately equalt to 1.4. SOD-A supraactivation is the effect of a genic dose, as demonstrated in earlier works (Sichitiu, 1973; Sichitiu et al., 1974; Sinet et al., 1974), whereas PGM hyperactivity appears to be modified secondarily, the same as the activity of other cellular enzymes in Down's disease.