SELENIUM STATUS IN INFANTS AND CHILDREN WITH PHENYLKETONURIA AND IN MATERNAL PHENYLKETONURIA

The selenium status was investigated in 87 patients of the German Coll aborative Study of Phenylketonuria (PKU) (mean age 9.7 years). The sel enium values and glutathione peroxidase activity in plasma and erythro cytes were negatively con-elated to the quality of dietary management (mean plasma phenylalanine value). Despite a low selenium state, the c hildren showed no clinical sign of deficiency and almost all biochemic al parameters checked were normal. In the low selenium state thyroxine values are increased and decline during selenium supplementation, whe reas tri-iodothyronine and thyroid stimulating hormone levels remain u nchanged, The reduction in glutathione peroxidase activity in plasma w as more pronounced than in the erythrocytes pointing to a different av ailability of both enzymes for selenium. In addition we estimated the selenium status in 29 women with PKU during pregnancy, In 32 healthy p regnant women we observed a decrease in plasma selenium values and the glutathione peroxidase activity in the third trimester, whereas the e rythrocyte glutathione peroxidase activity remained stable: In contras t to the healthy women we found in the PKU group a steady decrease of all selenium parameters tested during the whole pregnancy. During the long-term low-dose selenium supplementation in PKU children the glutat hione peroxidase activity of plasma and erythrocytes increased. They r eached a similar plateau after the application of inorganic or organic selenium compounds. In contrast the selenium values of plasma and who le blood showed only a plateau after the application of sodium selenit e, The supplementation with low doses of selenium in the form of selen omethionine increased the plasma and whole blood selenium values const antly within the first 9 months. Therefore selenomethionine supplement ation cannot be recommended.