MedGen

Abnormal thyroid hormone metabolism-3 (THMA3) is characterized by euthyroid hyperthyroxinemia, with elevated free T4 and reverse T3 levels, and normal TSH (see 188540) and free T3 levels. Patients also show low plasma selenium levels and reduced levels of stress-related selenoproteins (Schoenmakers et al., 2016; Geslot et al., 2021). For a discussion of genetic heterogeneity of abnormal thyroid hormone metabolism, see THMA1 (609698). [from OMIM]

Abnormal thyroid hormone metabolism-2 (THMA2) is characterized by elevated serum reverse triiodothyronine (rT3) levels and rT3/T3 ratios. Some patients exhibit resistance to thyroid-stimulating hormone (TSH; see 188540) with mildly elevated TSH levels, and elevated cholesterol levels have been observed (Franca et al., 2021). For a discussion of genetic heterogeneity of abnormal thyroid hormone metabolism, see THMA1 (609698). [from OMIM]