title: Cognitive outcomes in early-treated adults with phenylketonuria (PKU): A comprehensive picture across domains.
abstract: Phenylketonuria (PKU) is an inherited metabolic disease which affects cognitive functions due to an inability to metabolize phenylalanine which leads to the accumulation of toxic by-products (Phe) in the brain. PKU can be effectively treated with a low phenylalanine diet, but some cognitive deficits remain. Studies have reported impairments, especially for processing speed and executive functions, but there is a lack of comprehensive assessment across cognitive domains. Moreover, it is important to establish outcomes in early treated adults with PKU (AwPKU) who have better metabolic control than groups previously reported in the literature.
  
  
  
  We tested 37 AwPKU with an unprecedented number of tasks (N = 28) and measures (N = 44) and compared results with 30 controls matched for age and education.
  
  
  
  We found (a) group impairments, particularly in tasks tapping speed of processing and complex executive functions; (b) high variability across participants, with a sizable number of AwPKU with completely normal performance (about 38%); (c) but also a sizable number of participants who were clearly impaired (about 24%); and (d) good performance in tasks tapping verbal learning, verbal memory and orthographic processing, indicating no generalized learning impairment.
  
  
  
  Our results indicate good outcomes, but also that deficits are still present with current treatment policies. (PsycINFO Database Record
authors.affiliation: School of Life and Health Sciences, Aston University.
authors.forename: Liana
authors.initials: L
authors.lastname: Palermo
authors.affiliation: IMD Department, Queen Elizabeth Hospital.
authors.forename: Tarekegn
authors.initials: T
authors.lastname: Geberhiwot
authors.affiliation: IMD Department, Birmingham Children's Hospital.
authors.forename: Anita
authors.initials: A
authors.lastname: MacDonald
authors.affiliation: School of Life and Health Sciences, Aston University.
authors.forename: Ellie
authors.initials: E
authors.lastname: Limback
authors.affiliation: UK Newborn Screening Laboratories Network.
authors.forename: S Kate
authors.initials: SK
authors.lastname: Hall
authors.affiliation: School of Life and Health Sciences, Aston University.
authors.forename: Cristina
authors.initials: C
authors.lastname: Romani
mesh_terms: D000328:Adult; D001921:Brain / Q000378:metabolism; D003071:Cognition; D003072:Cognition Disorders / Q000209:etiology*; D004032:Diet; D061345:Early Medical Intervention; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D009483:Neuropsychological Tests; D010649:Phenylalanine / Q000172:deficiency*; D010661:Phenylketonurias / Q000150:complications / Q000178:diet therapy* / Q000523:psychology*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D010649:Phenylalanine