Two novel cysteine substitutions (C1263R and C1995S) of thyroglobulin cause a defect in intracellular transport of thyroglobulin in patients with congenital goiter and the variant type of adenomatous goiter.
Also, the presence of endoglycosidase H-resistant Tg as well as endoglycosidase H-sensitive Tg in the patients with the variant type of adenomatous goiter suggests that a fraction of C1995S Tg was transported to the Golgi and associated with the mildly increased serum Tg levels.