ABSTRACT
Objective: The imbalance of phenylalanine (PA) to tyrosine level and decreased dopamine brain level in patients with phenylketonuria (PKU) may have a role in their susceptibility of them to attention-deficit/hyperactivity disorder (ADHD). This study aimed to evaluate the frequency of ADHD in referred patients to PKU Clinic in Yazd, Iran. Materials & Methods: In this cross-sectional analytical study, all patients older than three years with PKU who were referred to the PKU Clinic of Shahid Sadoughi Hospital, Yazd, Iran, in 2018 were evaluated, and ADHD symptoms in them were assessed via parent face-to-face interview. The patients were diagnosed with ADHD if they scored at least of 20 on ADHD diagnostic rating scale via parent interview based on DSM-VI criteria. Results: Fourteen boys and 21girls with a mean age of 9.55±1.8 years were evaluated. 51.5% of those diagnosed with PKU had ADHD. Accordingly, ADHD was more frequent in girls (77.8% vs. 41% in boys, P=0.03). The mean age of diagnosis of PKU was significantly higher in patients with ADHD (52.54±15.65 months vs. 29.75±9.65 months, P = 0.03). The mean of PA level in the last six months (15.59±5.95 vs. 8.72+5.18, P= 0.005) and mean of the last six PA levels (14.76±4.71 vs. 8.96±3.86, P= 0.03) were significantly higher in ADHD group. Conclusion: The prevalence of ADHD in phenylketonuria patients in the present study was much more than in other studies. Late diagnosis of PKU and long-term high PA blood and brain level might be associated with increased neonatal screening. Hence, regular follow-up and continuous evaluation of patients with PKU for ADHD symptoms should be performed.
ABSTRACT
OBJECTIVE: Phenylalanine hydroxylase or its cofactor, tetrahydrobiopterin (BH(4)), deficiency causes accumulation of phenylalanine in body fluids and central nervous system. Considering the fact that hyperphenylalaninemia is a preventable cause of mental retardation in infants, the objective of this study was to determine the incidence of congenital hyperphenylalaninemia in Fars province, south of Iran. METHODS: In a period of one year from November 2007 to November 2008 blood samples were withdrawn from all newborns born in Fars province for measurement of serum phenylalanine. The samples with a serum level of≥ 2 mg/dl were referred to pediatric endocrine clinic for confirmation and determination of the type of hyperphenylalaninemia by quantitive serum phenylalanine measurements by using High-Pressure liquid chromatography (HPLC) method. FINDINGS: Nine out of 76966 newborns had a serum phenylalanine level≥2mg/dl, of which 8 cases were confirmed by HPLC. The incidence of the disease was 1:10000. The incidence of mild hyperphenylalaninemia and phenylketonuria (PKU) among the patients was 62.5% and 37.5% respectively and the incidence of BH(4) deficiency was 1/76966. CONCLUSION: These findings indicate a high incidence of hyperphenylalaninemia, in the newborns from Fars province. The high incidence makes a comprehensive screening program for management of the disease necessary.
