Endocrine Abstracts

Background: Iodine deficiency is the most important exogenous factor for the development of goiters and thyroid nodules. In addition, family and twin studies as well as linkage analyses and a genome-wide scan in 18 euthyroid goiter families suggest a genetic predisposition for euthyroid goiters. However, data about the inheritance of goiters are still contradictory. Therefore, we investigated goiter predisposition by a matched case control study.

Patients and methods: Three hundred and seventy-six patients providing written consent were included in the study. All of them were anti-TPO negative. We matched 188 patients with euthyroid or subclinically hyperthyroid goiter (TSH 4.20–0.05 mU/l) with 188 euthyroid controls without thyroid enlargement for age and gender. Family history of the patients was recorded using a standardised questionaire and thyroid ultrasound was performed for patients with goiter and controls.

Results: About 50.5% of patients with goiters showed a positive family history for goiter. In contrast, only 25% of patients with normal thyroids had a positive family history for goiter (P<0.001; OR=3.1). Patients with goiters had a significantly higher proportion of parents (P<0.001; OR=3.6) or siblings (P=0.004; OR=2.5) with goiters. Children of parents (mother and/or father) with goiters showed a 2.7-fold increased risk for goiter development and had a goiter prevalence of 73.3%. The primary diagnosis of goiter was made 10 years earlier in patients with a positive family history as compared to goitrous patients with a negative family history.

Conclusion: The significantly higher rate of positive family histories in patients with goiters as compared to the matched control patients as well as the increased goiter prevalence in children of parents with goiters indicate the importance of genetic factors in goiter development.

Additionally, the earlier onset of thyroid enlargement in case of a positive family history for goiter further supports a genetic predisposition in the aetiology of goiters.