ClinVar

Sunthornthepvarakul et al. (1998) reported an abnormal albumin in members of a Thai family that presented with high serum total T3 but not T4 when measured by radioimmunoassay. In contrast, total T3 values were very low when measured by ELISA and chemiluminescence. The subjects did not have a goiter and were clinically euthyroid. Their serum free T4, free T3, and TSH levels were normal (see 615999). Spiking of T3 to affected serum showed good recovery by radioimmunoassay but very poor recovery by ELISA and by chemiluminescence. Immunoprecipitation with labeled T3 bound to albumin showed a high percent of precipitation in affected serum. T3-binding studies showed that the association constant of serum albumin in affected subjects, 1.5 x 10(6)M(-1), was 40-fold that of unaffected relatives, 3.9 x 10(4)M(-1). The authors found a T-to-C (CTT-to-CCT) transition in the second nucleotide of codon 66, resulting in replacement of the normal leucine by proline.