[Malignant forms of phenylketonuria]

Forty-eight patients with pernicious phenylketonuria (PKU) were examined. It was revealed that the prognostically unfavourable symptoms in relation to the malignant course of the disease included early development of epileptic attacks and neurological disturbances, the small cranial size and early extensive eczematous lesions of the skin. It was established that children with pernicious PKU more often displayed high levels (over 30 mg/100 ml) of phenylalanine and low levels (under 1 mg/100 ml) of tyrosine in the blood as compared with other patients. The results of the study of families with two or more children with PKU suggest that the malignant course of the disease may be observed not only in primary genetic defect of the cofactor and the enzymes reducing it but also in the primary genetic defect of phenylalanine hydroxylase itself. The familial criteria of differentiating between various genetic forms of pernicious PKU are presented and the methods of its treatment are substantiated pathogenetically.