Weglage et al. investigated 57 adult patients with early-treated classical PKU (mean age 31 years) and 46 healthy controls, matched for age and socioeconomic status. MRI brain and evaluation for IQ, as well as for attention and information-processing were performed in all patients and controls. Neuropsychological assessments and MRI were repeated at a five-year-follow up. Over this interval, IQ, information processing and attention remained unchanged in both patients and controls. At both assessment times the IQ scores were significantly lower in patients compared to controls. Blood phenylalanine (Phe) levels during childhood and adolescence of PKU patients exhibited a significant correlation with IQ, information processing and attention but there was no correlation to imaging results. Older adult PKU patients showed poorer information processing and attention at both assessment times compared to young adult patients and controls. This seems to refer to an early relaxation of diet that was recommended when the older patients were adolescents. Neurocognitive outcome is better in those patients who continued their diet into early adulthood. These results indicate a benefit of dietary control during adolescence in PKU.
Neurocognitive functioning in adults with phenylketonuria: Results of a long term study J. Weglage, J. Fromm, A. van Teeffelen-Heithoff, H.E. Möller, B. Koletzko, T. Marquardt, F. Rutsch, R. Feldmann, http://www.sciencedirect.com/science/article/pii/S109671921300303X
posted by Yannis Trakadis, MD