Endocrine Abstracts

Background: Substantial deposition of iron in the thyroid gland is a frequent autopsy finding in patients with genetic haemochromatosis. Despite this there have been relatively few reports, mainly isolated cases, of significant thyroid dysfunction in such patients. In one large study Edwards et al. (1983) observed primary hypothyroidism in 6.1% of cases, all subjects were male and had elevated titres of antithyroid antibodies.

Aim: The aim of this prospective study is to assess the prevalence of thyroid dysfunction in a large group of patients with genetic haemochromatosis.

Results: A total of 154 patients (Male 123; Female 31) were studied prospectively. The average age for males was 52 years (range 25-76) and for females 54 years (range 24-82). 40 (25.9%) cases had diabetes mellitus and 24 cases had proven hepatitic cirrhosis. Genetic analysis in 127 patients revealed that 85.6% were C282Y homozygous, 1.6% H63D homozygous, 3.9% compound heterozygotes and 6.3% H63D heterozygotes. A total of 7 (4.5%) of patients were identified as having a thyroid disorder. Four (2.6%) had primary hypothyroidism, two had subclinical hypothyoidism and one had hypothyroidism secondary to pituitary surgery. In all cases the diagnosis of primary hypothyroidism preceded that of haemochromatosis. No case of hyperthyroidism has been identified. Thus despite apparently heavy iron deposition within the thyroid gland and genetic haemochromatosis thyroid function is preserved in the vast majority of patients.