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Abstract: The autoimmune thyroid diseases (AITDs) are multifactorial diseases which result from interplays between predisposing genes and triggering environmental factors. In order to study the genetic susceptibility factors to AITDs, we have followed up 115 control members belonging to a large Tunisian family with a high prevalence of AITDs (Akr family) during 15 years between 1990 to 2005. The follow-up of these control members have showed that 13 subjects (11.3%) developed AITDs (G2). The Hashimoto thyroiditis was the most frequently seen in 77% of the cases, whereas the Graves''s disease was present in 23% of the cases. One hundred and two members remained controls (G1). High female predominance was noted in the two groups. The mean age of the G1 subjects group was slightly higher than that of G2. The prevalence of positive antithyroglobulin antibody (TgAb) and antithyroperoxydase antibody (TPOAb) was more frequent in G2 group (P =0.27 and P =0.23) respectively. The HLA haplotypes was realized in 42% of control members. The most frequent HLA haplotypes that were found were B37, DRB11 and A1. HLA B37 and DRB11 were significantly more frequent for the patients of G2 (P =0.0001 and P =0.034) respectively. Our study confirms the contribution of the genetic factors in the development of AITDs in ‘Akr’ family and suggested that the members of this family share the same genetic inheritance. [Copyright &y& Elsevier]

In order to study incidence and prevalence of autoimmune thyroid diseases (AITDs), we studied a retrospective cohort of 1,079 patients explored in the department of Endocrinology of Sfax (south of Tunisia). The overall incidence of AITDs was 9.9%. Mean age was 39.6+15 years; sex ratio 5 F/1M. Graves' disease was the most frequent (45%). Atrophic thyroiditis was present in 32.2% of patients and Hashimoto's thyroiditis in 22.8%. The incidence of AITDs increased from 1990 to 2000 and by 2003 it had fallen to 67 cases per year. TPO antibody was present in two-thirds of patients with Hashimoto thyroiditis, and half of those with atrophic thyroiditis. TG antibodies were less frequent (one-third of patients). Association with other autoimmune diseases was noted in 6.3% of patients: type I diabetes mellitus, adrenal insufficiency and vitiligo. Statistic analysis did not disclose any association between autoantibody levels and thyroid dysfunction. There was an association between TG antibody and TSH levels among patients with Graves' disease and between TG antibody level and age in atrophic thyroiditis patients (p<0.05); a correlation was also noted between these antibodies and other autoimmune diseases (p=0.05). It is difficult to assess the frequency of ATD in the clinical setting. Characteristic features of AITDs in patients seen in south Tunisia were found to be similar to those described in the literature. Other more large-scale representative studies would be useful to establish the epidemiology of AITDs in Tunisia.