74 LONGTERM INTELLECTUAL DEVELOPMENT IN 86 CHILDREN WITH PHENYLKETONURIA (PKU)

Abstract

Dietary treatment in phenylketonuria (PKU) prevents severe impairment of psychomotor development. However, mere are unequivocal recommendations in regards to diet liberlization. Aim of this retrospective sfudy was to examine intellectual development in eighty-six individuals with “classical” PKU, who were treated early in life. Intellectual development was recorded using the Kramer, Hawik & Hawle test at the age of 4, 6, 8, and 12years. Intellectual development was not influenced by the time dietary treatment was started, probably due to the fact that treatment in all patients was introduced within the first two months (mean±SD: 23±8 days, range: 6 to 61 days). Compared with their non-PKU brothers and sisters PKU children showed significantly lower IQ at the age of 6 years (105±14 vs 114±14, P< 0.001). IQ of the parents did not differ from IQ of the PKU children at the age of 12 years. A significant association was observed between the quality of diet control (measured by Guthrie-test) and intellectual outcome: IQ at 6.8. and 12 years significantly correlated with qualify of diet control during all observation periods (r= 0.388. P<0.001). Children with “strict” dietary control - already at the age of 2 years-showed significantly higher IQ than those with “poor” dietary control. These observations underline the importance of a strict adherance of PKU patients to the diet to acchieve adequate intellectual development.