A Premature Stopcodon in Thyroglobulin Messenger RNA Results in Familial Goiter and Moderate Hypothyroidism

Abstract

Impaired thyroglobulin (Tg) synthesis is one of the putative causes for dyshormonogenesis of the thyroid gland. This type of hypothyroidism is characterized by intact iodide trapping, normal organification of iodide, and usually low serum Tg levels in relation to high TSH, and when untreated the patients develop goiter. In thyroid tissue from a 13-yr-old patient suspected of a thyroglobulin synthesis defect, the Tg mRNA was studied. The complete coding region of 8307 bp was directly sequenced and revealed a homozygous point mutation: a C886T transition in exon 7. Upon translation this mutation would result in a stopcodon at amino acid position 277, replacing the arginine residue. A Tg cDNA construct containing the mutation was