title: Behavioral and intellectual functioning in patients with tyrosinemia type I.
abstract: BACKGROUND
  In tyrosinemia type I (TT1) increased level of tyrosine and phenylalanine (both precursors of neurotransmitters), may potentially influence patients' cognitive development.
  
  
  OBJECTIVE
  Was to evaluate if the children during the treatment with phenylalanine- and tyrosine-restricted diet and nitisinone present with cognitive, emotional or behavioral problems and to find out whether plasma tyrosine and phenylalanine levels may have impact on this.
  
  
  METHODS
  Cognitive development and behavior, together with plasma tyrosine and phenylalanine levels, were analyzed in eight patients during their first five years of nitisinone treatment. Psychological examination has been done using standard diagnostic methods: the Wechsler Intelligence Scale for Children (WISC-R) and Child Behavior Checklist CBCL/4-18 (parents version).
  
  
  RESULTS
  The results showed that in the patients with TT1, attention deficit is not rare, and may be connected with the variation of the plasma tyrosine level. Moreover the reverse correlation between attention deficit and results from verbal scale may suggest decreased ability to verbal reasoning, comprehension, verbal expression and school difficulties.
  
  
  CONCLUSIONS
  What is significant for the presence of attention disorders and the related difficulties in using the intellectual potential is not the level of tyrosine (high vs. low), but its changes (stability vs. instability). Therapeutic trials to stabilize the tyrosine level could alleviate the difficulties in focusing attention. Following a diet is necessary for keeping the normal level of tyrosine.
authors.affiliation: Department of Pediatrics and Neonatology Central Clinical Hospital of Ministry of Internal Affairs, Warsaw, Poland. monika.pohorecka@cskmswia.pl
authors.forename: Monika
authors.initials: M
authors.lastname: Pohorecka
authors.forename: Marta
authors.initials: M
authors.lastname: Biernacka
authors.forename: Anna
authors.initials: A
authors.lastname: Jakubowska-Winecka
authors.forename: Marcin
authors.initials: M
authors.lastname: Biernacki
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Kuśmierska
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Kowalik
authors.forename: Jolanta
authors.initials: J
authors.lastname: Sykut-Cegielska
mesh_terms: D000293:Adolescent; D001289:Attention Deficit Disorder with Hyperactivity / Q000097:blood / Q000175:diagnosis / Q000209:etiology*; D002648:Child; D003072:Cognition Disorders / Q000097:blood / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D006801:Humans; D007361:Intelligence Tests; D008297:Male; D001523:Mental Disorders / Q000097:blood / Q000175:diagnosis / Q000209:etiology*; D010649:Phenylalanine / Q000097:blood; D011340:Problem Solving; D014443:Tyrosine / Q000097:blood; D020176:Tyrosinemias / Q000097:blood / Q000150:complications* / Q000178:diet therapy*; D014888:Wechsler Scales
chemical_list: D014443:Tyrosine; D010649:Phenylalanine