Assessment of the function and morphology of the thyroid gland in paediatric patients treated with enzyme replacement therapy due to selected storage diseases - preliminary results of our own research and a review of the literature.

INTRODUCTION: Some storage diseases, caused by a deficiency of a specific enzyme, which results in the systemic accumulation of non-metabolized substances, can be treated with enzyme replacement therapy (ERT), which can protect many organs, including the endocrine system. AIM: The aim of the study was to assess the function and morphology of the thyroid gland in children with storage diseases treated with ERT, and to review the literature. MATERIAL AND METHODS: Eight patients were included in the study: 3 with Fabry disease (age: 17; 9.9; 10 years), 3 with Hunter's disease (12.3; 4.1; 9,3), and 2 with Pompe disease (6.8; 9,5). Thyroid function and morphology were assessed in each patient during ERT, and 4 of them were reassessed 27 months later. RESULTS: One patient with Fabry disease had been treated for hypothyroidism due to autoimmune thyroiditis diagnosed before the study. The remaining patients had normal thyroid tests and negative anti-thyroid antibodies at first and second evaluation; however, in all reassessed patients a decrease in TSH value was noted. Among the remaining patients with Fabry disease, one had normal and a second had heterogeneous echogenicity of the thyroid during first assessment. In the second patient, normalisation of echogenicity was observed at reassessment. Both patients with Pompe disease assessed once had slightly heterogeneous thyroid echogenicity. In 3 patients with Hunter's disease in the first ultrasound examination, no abnormalities were found. In re-evaluation, 2 of them showed heterogeneous thyroid echogenicity. CONCLUSIONS: We conclude that patients with storage diseases should undergo assessment of thyroid function and morphology before and during ERT.

Carriership of the rs113883650/rs2287120 haplotype of the SLC7A5 (LAT1) gene increases the risk of obesity in infants with phenylketonuria.

PURPOSE: Phenylketonuria (PKU) can be effectively treated with the use of a low-phenylalanine diet. However, some patients become overweight despite proper dietary treatment. We hypothesized that this phenomenon could be explained by the presence of specific variants within the genes involved in phenylalanine transport or in the phenylalanine transamination/oxygenation pathway. METHODS: We selected a clinically homogenous group of 100 infants with PKU and assessed their growth patterns in the context of dietary phenylalanine tolerance. Next, within the sample, we performed exome sequencing and assessed a potential relationship between the observed phenotypical variability and the presence of structural variants in a priori selected genes of interest. RESULTS: We detected a highly significant association between overweight and carriership of the rs113883650/rs2287120 haplotype of the SLC7A5 (LAT1) gene, which encodes the main transmembrane transporter of large neutral amino acids and of thyroid hormones. CONCLUSIONS: Our findings suggest a pharmacogenetic effect of the relatively common rs113883650/rs2287120 haplotype of the SLC7A5 gene. This can have practical implications for patients with PKU, since treatment protocols need to be reassessed to better prevent overweight in the carriers of the above variant.

[Early enzyme replacement therapy - hope for patients with mucopolysaccharidosis Type II]. / Wczesna enzymatyczna terapia substytucyjna ­ nadzieja dla chorych na mukopolisacharydoze typu II.

We present an unexpected outcome of 10 years of enzyme replacement therapy of a boy with mucopolysaccharidosis type II. Due to a positive familiar history (severe disease course in a sibling) the diagnosis was established in the first month of life. Treatment with Elaprase was introduced two months later. Since then normal physical and mental development is observed. The patient presents only relatively large head circumference (+2.1 SD) and slight decrease of joints mobility. In our opinion, early introduction of enzyme replecement therapy could attenuate the disease course.