Development of the phenylketonuria screening programme in Estonia.

OBJECTIVE: To develop the phenylketonuria (PKU) screening programme in Estonia.

METHOD: All data about patients with PKU, born during 1980-92, were documented to establish its prevalence at birth in Estonia. Newborn screening for the diagnosis and treatment of PKU was started in Estonia in 1993 and the prevalence at birth established by screening. Phenylalanine was determined from filter paper blood by a modified fluorometric method based on enhancement of the fluorescence of a phenylalanine-ninhydrin reaction product by L-leucyl-L-alanine.

RESULTS: During three years (1993-5) 36,074 newborns (85% of the total) were screened for PKU. PKU was diagnosed in six cases during the first four to six weeks of life. All investigated cases could be classified as classical PKU. No cases of mild forms of hyperphenylalaninaemia were diagnosed. The retrospective study showed an average incidence of PKU of 1 in 8090, the prospective study identified a comparable incidence of 1 in 6010 live births.

CONCLUSION: The prevalence at birth of classic PKU in Estonia is higher than the average in Europe and similar to that of some eastern and middle European countries.