Single base mutation in the hormone binding domain of the thyroid hormone receptor β gene in generalised thyroid hormone resistance demonstrated by single stranded conformation polymorphism analysis

Abstract

Thyroid hormone resistance is a syndrome of considerable clinical heterogeneity. Three mutations in the c-erb A β gene encoding the human β thyroid hormone receptor have been described in different kindreds. We report here, in a family affected with peripheral thyroid hormone resistance, a unique point mutation in the ligand binding domain of the c-erb A β gene resulting in histidine replacement of an arginine residue at position 438. The region in which the mutation occurred was identified by single stranded conformation polymorphism analysis and confirmed by subcloning and sequencing of the mutant alleles from each of the affected members. Binding of tri-iodothyronine to isolated nuclei from family members was normal suggesting the mechanism of thyroid hormone resistance in this family is not mediated by abnormal binding of ligand and receptor.