Executive dysfunction in treated phenylketonuric patients.
OBJECTIVE
Executive function deficits have been described in early and continuously treated patients with phenylketonuria (PKU). The aim of this study was to examine performance on executive function tasks of treated patients with PKU diagnosed by 2 years of age.


METHODS
Ten patients with PKU and normal intelligence score who were diagnosed before the age of 2 years and subsequently treated continuously, were compared with 15 typically developing control children on a battery of neuropsychological tests, including the tower of London (TOL), continuous performance test (CPT), and Stroop test.


RESULTS
PKU cases showed significantly poorer performance on the TOL task compared to the control group with the difference being significant in the first three levels of the test. With the CPT, PKU cases had significantly more omission errors than control subjects. On the Stroop test there was no statistically significant difference between the groups. No significant correlation was found between the concurrent serum phenylalanine (Phe) level and results of the executive tests in PKU patients.


CONCLUSIONS
This study identified executive dysfunction in early-treated PKU patients with normal IQ, particularly in the planning and attention domains. Further studies are required to compare the results with those from other neurodevelopmental disorders such as ADHD and autism, to establish whether the pattern of findings is specific to PKU.
Azadi
Bahare
B
Child and Adolescent Psychiatry Dept., Institute of Psychiatry, King's College London, London, UK. bahare.azadi@iop.kcl.ac.uk
Seddigh
Arshia
A
Tehrani-Doost
Mehdi
M
Alaghband-Rad
Javad
J
Ashrafi
Mahmoud Reza
MR
D000293:Adolescent; D016022:Case-Control Studies; D002648:Child; D003072:Cognition Disorders / Q000175:diagnosis* / Q000209:etiology*; D005260:Female; D006801:Humans; D007360:Intelligence; D008297:Male; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D010661:Phenylketonurias / Q000150:complications* / Q000628:therapy; D011340:Problem Solving; D011594:Psychometrics; D011930:Reaction Time; D012016:Reference Values; D012920:Social Behavior Disorders / Q000175:diagnosis* / Q000209:etiology; D055815:Young Adult