Longitudinal study on early diagnosis and treatment of phenylketonuria in Poland

Abstract

Early diagnosis and treatment of phenylketonuria (PKU) in Poland was started in 1965, initially on a voluntary and then on a obligatory basis. Guthrie tests have been used for newborn screening. For confirmation of diagnosis changing with time methods of blood phenylalanine (Phe) and tyrosine estimation were used. In addition, Phe and its urinary metabolites were estimated. A total of 560 cases of classical PKU, 99 mild hyperphenylalaninaemia and six atypical PKU cases were detected. The age of confirmatory estimations was from the 1st to 3rd month, in some cases above 3 months. Pretreatment Phe levels ranged from 12.5 to 70.7 mg/dl. The diet was started on a hospital basis and continued at home, controlled with Guthrie tests with age dependent frequency. Periodical multidimensional controls allowed evaluation of physical and mental development, together with biochemical scores (Hb, RBC, total plasma protein, Phe and tyrosin). In some patients trace elements (copper, iron, zinc and selenium) were also determined. Physical development of treated patients was normal. Biochemical scores presented transient relatively low Hb and iron concentrations especially in the youngest patients. DQ/IQ scores correlated with dietary control and social environment. In adults (age 19-26 years) off diet, mean IQ was 97.2 +/- 15.5 in those with good dietary control and 81.0 +/- 13.8 in those poorly controlled during treatment. In adults the average level of education attained was various types of professional school. Some patients attended or graduated from university.