Intelligence Quotient and Its Affected Epidemiological Factors in Children with Phenylketonuria in Hamadan Province

Abstract

Background and Objectives: Phenylketonuria (PKU) is a rare hereditary metabolic disease caused by the phenylalanine hydroxylase enzyme (PAH) deficit. Delays in diagnosis and treatment have serious effects on the nervous system and reduce the IQ of these children. Materials and Methods: The current cross-sectional study was conducted on 55 children aged 5 to 18 years with a definite diagnosis of PKU who were taken care of in the Genetic Diseases Control Center, Hamadan Be'sat Hospital. The information of the patients was obtained from the file and interviews with the parents and then recorded in the checklist. For individual measurement of cognitive abilities and IQ, the Stanford Binet Questionnaire was used, and statistical analyses were performed in Stata 16 software. Results: The average age of the children was 11.08 years,52.73% of the samples were children of consanguineous marriage parents, and 29.09% had a history of PKU in the family. The average age of diagnosis was 15.09 months. The disease had been diagnosed in 47% of cases by screening. The IQ of 3.5% of the children was normal, 42% was low average, 43.5% had borderline much lower than average, and 11% suffered from mental retardation. The average age of diagnosis was 5, 15, 13, and 27.5 months, respectively. A significant relationship was found between IQ and the child's age and birth order (P<0.05), disease diagnosis through screening (P=0.009), incidence of failure to thrive disorder (P=0.006), and incidence of specific developmental disorder (P=0.002). Conclusion: Early diagnosis and treatment of PKU by screening have an important role in preventing mental retardation. Higher birth order and increasing age are associated with a decrease in IQ; therefore, periodic assessment of IQ is necessary for the educational planning of these patients.

Keywords

• intelligence quotient
• phenylketonuria
• stanford-binet