Emotional and behavioural functioning in children with tyrosinaemia type 1

Introduction
Tyrosinaemia type I is a rare hereditary metabolic disease caused by deficiency of the enzyme involved in the breakdown of tyrosine. Since the use of nitisinone in addition to diet in 1992, survival rates have increased significantly, but more and more socio-emotional problems have become apparent. The aim of the study was the assessment the relationship between variations in serum tyrosine and phenylalanine levels and measurements of socio-emotional functioning and determination of patients’ IQs.

The aim of the study
was the assessment the relationship between variations in serum tyrosine and phenylalanine levels and measurements of socio-emotional functioning and determination of patients’ IQs.

Material and methods
Twelve children were studied, from a single centre, born between 1994 and 2012, treated with nitisinone and a low-phenylalanine and -tyrosine diet. The psychological evaluation was conducted using the parent form of the Child Behaviour Checklist (CBCL)/4–18. Additionally, the patients’ IQs were measured using the Stanford-Binet 5 (SB5) Intelligence Scale. Statistical analyses were performed using PAWS software suite version 26. We found that phenylalanine variability over time correlated with measures of emotional and behavioural functioning. This relationship holds true for externalising behaviour, associated with the experience of maladjustment and aggression. Total score intellectual and cognitive function was within the norm for all patients.

Conclusions
To maintain better quality of life for patients and their families in terms of emotional and behavioural functioning, it may be important to avoid spikes (significant fluctuations) in phenylalanine levels. Regular, detailed psychological evaluations are recommended to detect potential problems and implement interventions aimed at achieving the best possible individual development and realise the intellectual and behavioural potential, thereby improving the patient's and her family's quality of life.