Functional analysis of a proline to serine mutation in codon 453 of the thyroid hormone receptor {beta}1 gene
- Univ. of Toronto, Ontario (Canada); and others
Mutations in the gene encoding human thyroid hormone receptor {beta}(hTR{beta}) have been associated with generalized resistance to thyroid hormone (GRTH). This disorder is associated with significant behavoral abnormalities. We examined the hTR{beta} gene in a family with members who manifest inappropriately normal TSH, elevated free T{sub 4}, and free and total T{sub 3}. Sequence analysis showed a cytosine to thymine transition at nucleotide 1642 in one allele of the index patient`s genomic DNA. This altered proline to serine at codon 453. The resulting mutant receptor when expressed in vitro bound DNA with high affinity, but the T{sub 3} affinity of the receptor was impaired. The mutant TR demonstrated a dominant negative effect when cotransfected with two isoforms of wild-type receptor and also in the presence of TR variant {alpha}2 in COS-1 cells. Mutations of codon 453 occur more frequently than at other sites, and four different amino acid substitutions have been reported. Significant differences in phenotype occur among affected individuals, varying from normality to moderately severe GRTH. There is no clear correlation between K{sub a} or in vitro function of the mutant receptor, and phenotype. This study extends the association between GRTH and illness, and indicates that early diagnosis and counseling are needed in families with TR{beta}1 abnormalities. 34 refs., 5 figs., 2 tabs.
- OSTI ID:
- 443619
- Journal Information:
- Journal of Clinical Endocrinology and Metabolism, Vol. 80, Issue 10; Other Information: PBD: Oct 1995
- Country of Publication:
- United States
- Language:
- English
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