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Endemic cretinism: possible role for thyroid autoimmunity
S C Boyages1, J P Halpern, G F Maberly
1Department of Medicine, Westmead Hospital, Sydney, Australia.
Lancet (London, England)
|September 2, 1989
Summary
Thyroid atrophy in myxoedematous endemic cretinism is linked to specific IgG antibodies that block thyroid growth. This discovery explains the varied clinical presentations of this condition.
Area of Science:
- Endocrinology
- Immunology
- Genetics
Background:
- Thyroid atrophy is a key feature of myxoedematous cretinism, but its cause remains unclear.
- Endemic cretinism presents with variable clinical manifestations, including neurological and thyroidal abnormalities.
Purpose of the Study:
- To investigate the role of immunoglobulin G (IgG) in the pathogenesis of thyroid atrophy in myxoedematous endemic cretinism.
- To identify potential pathogenic factors contributing to the diverse clinical outcomes in endemic cretinism.
Main Methods:
- Purified IgG fractions from patients with myxoedematous endemic cretinism were tested for their effect on thyrotropin-induced DNA synthesis in guinea pig thyroid segments using a cytochemical bioassay.
- Serum IgG from euthyroid endemic cretinism patients and normal subjects served as controls.
- Ultrasound was used to assess thyroid atrophy in myxoedematous subjects.
Main Results:
- IgG from patients with myxoedematous endemic cretinism significantly inhibited thyrotropin-induced DNA synthesis in guinea pig thyroid segments.
- IgG from euthyroid endemic cretinism patients and normal subjects did not show inhibitory effects on thyroid growth.
- A positive correlation was observed between the presence of thyroid-growth-blocking immunoglobulins and thyroid atrophy in myxoedematous subjects.
Conclusions:
- Thyroid-growth-blocking immunoglobulins in IgG fractions from myxoedematous endemic cretinism patients play a pathogenic role in thyroid atrophy.
- These findings provide a molecular basis for the variable clinical expression of endemic cretinism, linking specific autoantibodies to thyroid pathology.