The selenium state of children. II. Selenium content of serum, whole blood, hair and the activity of erythrocyte glutathione peroxidase in dietetically treated patients with phenylketonuria and maple-syrup-urine disease.

The selenium content of serum, whole blood and hair was measured by neutron activation analysis in dietetically treated patients with phenylketonuria (PKU) and maple-syrup-urine disease (MSUD). Follow-up studies showed a decrease of the serum selenium content and the glutathione peroxidase activity of erythrocytes--a selenoenzyme--from normal values at the beginning of the diet to 20% (selenium) and 50% (gluthione peroxidase) of normal within 10--12 weeks of dietary treatment. In 36 patients the serum selenium content was lower at 6.7--28 X 10(-9) g/ml, independent of the age of the patients (0.5 to 10 years). The selenium content of whole blood was reduced: median = 98 X 10(-9) g/g dry weight; range 75 to 165 X 10(-9) g/g dry weitht (healthy children: median = 381 X 10(-9) g/g dry weight; range 245 to 588 X 10(-9) g/g dry weight). The selenium content of hair was markedly lower in the patients (median = 62 X 10(-9) g/g; range 13--140 X 10(-9) g/g) than in healthy children (median = 429; range 213 to 720 X 10(-9) g/g). The mean glutathione peroxidase activity of erythrocytes was reduced to 4.6 +/- 0.64 U37/g Hb, comparison to normal values (mean = 8.8 +/- 0.88 U37/g Hb).