Molecular diagnosis in suspected patients with thyroglobulin and thyroperoxidase deficiencies

Abstract

Inborn thyroid hormone synthesis errors or dishormonogenesis account for 10-15% of congenital hypothyroidism patients. The molecular diagnosis validates the etiologic diagnosis, helping to distinguish between different defects and genetic counseling. The most common defects are iodine organification defect, caused by mutation in thyroperoxidase (TPO) and THOX2 and thyroglobulin (TG) defect, caused by mutation in TG gene. Iodine uptake is always elevated in all with rapid decline in iodine clearance thus the iodine organification and thyroid hormone synthesis defects are not distinguished. Therefore, intravenous perchlorate test helps to discern these etiologies. In our ongoing study, intravenous perchlorate test, together with TG levels allowed identifying the defects, but we noted diagnosis overlapping. The mutation identification will help to confirm, explain and stipulate perchlorate test values and TG levels that classify most common dishormonogenesis etiologies. (AU)