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Resistance to thyroid hormone in a Chinese family
with R429Q mutation in the thyroid hormone receptor beta gene
APS Kong, CW Lam, AOK Chan,
SF Yiu, SC Tiu
Department of Medicine, Queen Elizabeth Hospital, 30 Gascoigne Road,
Hong Kong
The combination of elevated serum levels of free
thyroid hormones with non-suppressed thyroid-stimulating hormone
suggests the differential diagnoses of resistance to thyroid hormone
or thyroid-stimulating hormone–secreting pituitary tumour.
Clinical differentiation of these two conditions can be difficult,
because patients with thyroid hormone resistance may exhibit various
combinations of hypermetabolic and hypometabolic features, and laboratory
results have limited sensitivity and specificity. We report a case
of resistance to thyroid hormone in a Chinese family that illustrates
this difficulty. The diagnosis could only be confirmed by the identification
of a known disease-causing mutation in the thyroid hormone receptor
beta gene in peripheral leukocytes. Availability of genetic tests
will identify more cases in the future and improve our understanding
of this condition.
Hong Kong Med J 2005;11:125-9
Key words: Chinese; Thyroid hormone receptors beta;
Thyroid hormone resistance syndrome
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