Girl With Tyrosinemia Type 1 and Executive Dysfunctions Treated With Methylphenidate: A Case Report

Abstract Hereditary tyrosinemia type 1 (HT1; OMIM 27670) is an inborn error of tyrosine metabolism, caused by a deficiency of the enzyme fumarylacetoacetate hydrolase. This defect leads to accumulation of toxic products, which cause liver and kidney dysfunction. In patients with HT1, IQ, executive functioning, and social cognition are also affected. We report here a case report of a Belgian 11-year-old girl of Moroccan ethnicity with HT1. She had attention problems, which had a significant impact on her school functioning. Neuropsychological tests showed very low scores for processing speed and executive functioning. Therapies such as adaptations in the school and private tutoring were not sufficient to improve this. Treatment with methylphenidate showed a significant improvement in the neuropsychological test and school functioning. This case shows the importance of being alert for problems with executive functions in patients with HT1 and to consider psychopharmacological treatment.

Newborn Screening for Lysosomal Storage Disorders in Belgium The Importance of Sex- and Age-Dependent Reference Ranges

Abstract Lysosomal storage disorders (LSDs) are a group of metabolic disorders with various clinical presentations, which complicate diagnosis. A pilot study was performed to test the appropriateness and effectiveness of the newborn screening method for Pompe disease, Fabry disease and mucopolysaccharidosis (MPS) I in dried blood spots using liquid chromatography-tandem mass spectrometry. Around 20 000 newborn samples were analyzed for 3 lysosomal enzyme activities: ?-glucosidase (deficient in Pompe disease), ?-galactosidase (deficient in Fabry disease) and ?-iduronidase (IDUA, deficient in MPS I). Data were used for statistical analysis and to establish sex- and age-dependent reference ranges. Statistically significant higher ?-glucosidase, ?-galactosidase, and IDUA enzyme activities were observed in female newborns compared to male newborns. Newborns with a higher gestational age have a statistically significant lower ?-glucosidase, ?-galactosidase, and IDUA enzyme activities compared to newborns with a lower gestational age. For the first time, the data of a large-scale LSD study were used to assess statistical differences in enzyme activity in the newborn population, and these data highlight the importance of using reference intervals for lysosomal enzyme activities in function of sex and gestational age.