Session: SUN 596-623-Case Reports: Pediatric Endocrinology & Metabolism
Poster Board SUN-618
Clinical cases: Case 1 is an 8-year-old boy. Pregnancy and delivery were uneventful. There was no family history of thyroid disorders or delay in neurological development. Poor weight gain and hypotonia with poor head control were pointed out at age 4 months. Brain MRI showed delayed myelination at age 1 year. At present, severe mental retardation, poor head control, reduced muscle mass, hypotonia and short stature are found. On current thyroid function test, serum levels of TSH, FT3 and FT4 were 2.44 mIU/ml, 4.2 pg/ml and 0.6 ng/dl, respectively. Case 2 is a 20-year-old boy. Pregnancy and delivery were not complicated. There was no family history of thyroid disorders or delay in neurological development. Growth and developmental delay were pointed out, and brain MRI showed delayed myelination at age 1 year. At present, severe mental retardation, inadequate head control, reduced muscle mass, quadriplegia and short stature are found. Recent thyroid function revealed serum levels of TSH, FT3 and FT4 of 7.09 mIU/ml, 6.2 pg/ml and 0.3 ng/dl, respectively.
SLC16A2 gene analysis: SLC16A2 gene analysis was performed for our two patients, because MCT8 abnormality was suspected. A missense hemizygous mutation in exon 4 (p.R445S) of Case 1 and a missense hemizygous mutation in exon 1 (p. G196E) of Case 2 were identified. Those were novel mutations.
Endocrinological studies: Thyroid function tests showed the typical pattern for MCT8 abnormality in both Case 1 and 2. However, euthyroid was detected in early childhood for either case. TRH test revealed the pituitary hypothyroid pattern of TSH in Case 1. Brain MRI and cervical echogram demonstrated atrophy of the pituitary and thyroid glands. In Case 2, GH deficiency and Gonadotropin deficiency were detected, and TRH test revealed the primary hypothyroid pattern of TSH. Brain MRI and cervical echogram demonstrated atrophy of the pituitary gland and enlargement of the thyroid gland.
Conclusion: Our findings suggest that thyroid status of MCT8 abnormality is changeable according as the time of examination, and therefore regular thyroid function test is necessary for suspicious patients of MCT8 abnormality. Additionally, we should take care in that various patterns are found with regard to pituitary dysfunction and the size of thyroid gland in MCT8 abnormality.
Nothing to Disclose: EO, MA, SO, MH, MI, YO, SM, IM, NN, KO, HI
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