DNA-based diagnosis of thyroid hormone resistance syndrome: a novel THRB mutation associated with mild resistance to thyroid hormone.
BACKGROUND
Thyroid hormones govern a wide range of metabolic processes in the body via thyroid hormone receptors (TR). We report a patient with mild resistance to thyroid hormone who was initially misdiagnosed and treated as having thyrotoxicosis.


METHODS
We used direct DNA sequencing of the THRB gene.


RESULTS
We identified a novel missense mutation, I276L, located in exon 8 of the gene. The mutation is located in cluster 3 of the ligand-binding domain, a protein domain associated with resistance to thyroid hormone.


CONCLUSIONS
DNA-based diagnosis of thyroid hormone resistance syndrome is simple, reliable, and economical compared to traditional biochemical tests. Once the mutation is identified, targeted screening for the whole family can be performed and the unnecessary use of anti-thyroid drugs or thyroidectomy can be avoided.
Lam
Ching-Wan
CW
Department of Chemical Pathology, The Chinese University of Hong Kong, Prince of Wales Hospital, Hong Kong, China. ching-wanlam@cuhk.edu.hk
On-Kei Chan
Angel
A
Tong
Sui-Fan
SF
Shek
Chi-Chung
CC
Cheung Tiu
Sau
S
D000328:Adult; D004252:DNA Mutational Analysis / Q000379:methods; D005192:Family Health; D006801:Humans; D008297:Male; D020125:Mutation, Missense; D010375:Pedigree; D037042:Thyroid Hormone Receptors beta / Q000235:genetics* / Q000378:metabolism; D018382:Thyroid Hormone Resistance Syndrome / Q000175:diagnosis* / Q000235:genetics*; D013963:Thyroid Hormones / Q000235:genetics* / Q000378:metabolism; D013997:Time Factors
D037042:Thyroid Hormone Receptors beta; D013963:Thyroid Hormones