Thyroid Disorders in Mental Patients
Thyroid Disorders in Mental Patients
Thyroid hormones regulate brain developmental events such as neurogenesis, myelination, and synapse formation; insufficient thyroid hormone results in mental retardation. Mutations in MCT8 affect T3 transport into neurons causing brain hypothyroidism with elevated serum T3 concentrations. Clinical features of MCT8 mutations present as severe mental retardation, axial hypotonia, and absence of speech. Visser et al. reported that MCT8 mutations were found in all families with AHDS, suggesting a molecular basis for this syndrome.
In 2008, several new AHDS cases were reported, including the case of first female patient with AHDS and a novel MCT8 mutation in an 11-month-old male infant with severe neonatal hypotonia and development delay. Sijens et al. used brain MRI in two young children with MCT8 mutation. The results were compared with data from controls of a similar age. MCT8 gene mutation resulted in deviant myelinization and in general atrophy of the brain which substantiated magnetic resonance spectroscopy (MRS) findings of increased choline and myoinositol concentrations and decreased N-acetyl aspartate concentrations. Different mutations in the MTC8 transporter led to different expression of dysmyelinization and to different changes in brain metabolism.
Mental Retardation and Monocarboxylate Transporter-8 Mutation
Thyroid hormones regulate brain developmental events such as neurogenesis, myelination, and synapse formation; insufficient thyroid hormone results in mental retardation. Mutations in MCT8 affect T3 transport into neurons causing brain hypothyroidism with elevated serum T3 concentrations. Clinical features of MCT8 mutations present as severe mental retardation, axial hypotonia, and absence of speech. Visser et al. reported that MCT8 mutations were found in all families with AHDS, suggesting a molecular basis for this syndrome.
In 2008, several new AHDS cases were reported, including the case of first female patient with AHDS and a novel MCT8 mutation in an 11-month-old male infant with severe neonatal hypotonia and development delay. Sijens et al. used brain MRI in two young children with MCT8 mutation. The results were compared with data from controls of a similar age. MCT8 gene mutation resulted in deviant myelinization and in general atrophy of the brain which substantiated magnetic resonance spectroscopy (MRS) findings of increased choline and myoinositol concentrations and decreased N-acetyl aspartate concentrations. Different mutations in the MTC8 transporter led to different expression of dysmyelinization and to different changes in brain metabolism.
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