A one year old child preents with sho stature, lethargy, & constipation. Clinical examination shows a palpable goiter. Laboratory investigations revealed a low T4 and elevated TSH which of the following is the most likely diagnosis

Thyroid dyshormonogenesis is a rare condition due to genetic defects in the synthesis of thyroid hormones. Patients develop hypothyroidism with a goiter. It is due to either deficiency of thyroid enzymes, inability to concentrate, or ineffective binding. Responsible for 10-15 % cases of permanent hypothyroidism. Synthetic defects in thyroid hormone production. Abnormal thyroid peroxidase activity is the commonest one, leading to impaired oxidation and organification of iodine. Autosomal Recessive inheritance, 25% increased risk in subsequent siblings. Goiter may be present, low total and free T4 levels, elevated TSH, and normal TBG. Thyroglobulin (TG) is low in TG synthetic defects and is high in other thyroid hormone synthetic defects. Imaging: Normally placed thyroid gland, which may be of normal size or enlarged. In cases with paial deficiency, onset of signs and symptoms is delayed. Reference: GHAI Essential pediatrics, 8th edition