Impact of Early Intervention with Triiodothyroacetic Acid on Peripheral and Neurodevelopmental Findings in a Boy with MCT8 Deficiency

J Clin Res Pediatr Endocrinol. 2023 Dec 6. doi: 10.4274/jcrpe.galenos.2023.2023-10-1. Online ahead of print.ABSTRACTMonocarboxylate transporter8 (MCT8) deficiency is a rare genetic disorder characterized by peripheral thyrotoxicosis and severe cognitive, motor disability due to cerebral hypothyroidism. 3,3',5-triiodothyroacetic acid(Triac) was shown to improve peripheral thyrotoxicosis but data on neurodevelopmental outcome are scarce. Herein a case of MCT8 deficiency and the experience with Triac focusing on change in neurodevelopmental and peripheral features are being presented. Five-month-old boy was referred for feeding difficulty, central hypotonia and global developmental delay. Despite six months of physiotherapy, physical developmental milestones did not improve, and distal muscle tone was increased. Hemizygous pathogenic variant in SLC16A2 was found, MCT8 deficiency was confirmed. TSH was 2.83 mIU/ml, free thyroxine:6.24pmol/L (N:12-22) and free triiodothyronine(FT3):15.65pmol/L (N:3.1-6.8). He had tachycardia, blood pressure and transaminases were elevated. Triac was started at 21-months. Two weeks after treatment, FT3 dramatically decreased, steady normal serum FT3 was achieved at 28-months. Neurodevelopmental milestones, signs of hyperthyroidism were evaluated at baseline, 6 months and 12 months after treatment. Signs of hyperthyroidism were improved by 6 months. Developmental composite scores of Bayley Scales of Infant Developmental 3rd Edition remained the same...
Source: JCRPE Journal of Clinical Research in Pediatric Endocrinology - Category: Endocrinology Authors: Source Type: research