The authors present an analysis of a cohort of patients suffering from phenylketonuria during adolescence and at the adult age having been treated in the Center for diagnosis and therapy of hyperphenylalaninemia located in Bratislava. Within the framework of the observation the authors paid attention to the number of patients, mean age, distribution according to sex and age, the frequency of control examinations and visits, analysis of the late diagnosis of the disease, education in relation to the age groups, therapy of the patients, type of treatment and the results of psychological examination.

        Key words: hyperphenylalaninemia, phenylketonuria in adolescents and adult individuals