Genetic variants and risk of endocrine autoimmunity in relatives of patients with Addison's disease.

Since individuals with Addison's disease (AD) present considerable co-occurrence of additional autoimmune conditions, clustering of autoimmunity was also predicted among their relatives. The study was aimed to assess circulating autoantibodies in first-degree relatives of patients with AD and to correlate them with the established genetic risk factors (PTPN22 rs2476601, CTLA4 rs231775, and BACH2 rs3757247). Antibodies were evaluated using validated commercial assays, and genotyping was performed using TaqMan chemistry. The studied cohort comprised 112 female and 75 male relatives. Circulating autoantibodies were found in 69 relatives (36.9%). Thyroid autoantibodies, that is antibodies to thyroid peroxidase (aTPO) and thyroglobulin (aTg), were detectable in 25.1 and 17.1% relatives, respectively. Antibodies to 21-hydroxylase (a21OH) were found in 5.8% individuals, and beta cell-specific antibodies to ZnT8, GAD, and IA2 were found in 7.5, 8.0, and 2.7%, respectively. The prevalence of a21OH (P = 0.0075; odds ratio (OR) 7.68; 95% CI 1.903-36.0), aTPO (P < 0.0001; OR 3.85; 95% CI 1.873-7.495), and aTg (P < 0.0001; OR 7.73; 95% CI 3.112-19.65), as well as aGAD (P = 0.0303; OR 3.38; 95% CI 1.180-9.123) and aZnT8 (P = 0.032; OR 6.40; 95% CI 1.846-21.91), was significantly increased in carriers of rs2476601 T allele. Moreover, T allele appeared to be a risk factor for multiple circulating autoantibody specificities (P = 0.0009; OR 5.79; 95% CI 1.962-15.81). None of the studied autoantibodies demonstrated significant association with rs231775 in CTLA4 (P > 0.05), and only weak association was detected between BACH2 rs3757247 and circulating aTPO (P = 0.0336; OR 2.12; 95%CI 1.019-4.228). In conclusion, first-degree relatives of patients with AD, carriers of the PTPN22 rs2476601 T allele, are at particular risk of developing autoantibodies to endocrine antigens.

Aggregation of autoimmunity in extended families of people with autoimmune Addison disease.

BACKGROUND: Autoimmunity accounts for 90% of cases of primary adrenal insufficiency (Addison disease (AD)). Affected people present a significant co-occurrence of autoimmune conditions; hence, clustering of autoimmunity is also predicted among their relatives. AIMS: To evaluate the burden of autoimmunity in families of people with AD. METHODS: A total of 116 individuals with AD was surveyed regarding the occurrence of 23 autoimmune diseases among their relatives. RESULTS: A total of 74.1% of persons with AD reported at least one relative with an autoimmune disorder - 257 cases were diagnosed in 221 relatives. Hashimoto thyroiditis was found in 100 individuals, followed by Graves disease and vitiligo, in 25 and 24 relatives respectively. Type 1 diabetes was diagnosed in 23 relatives, psoriasis in 15, rheumatoid arthritis in 12, pernicious anaemia in 11, multiple sclerosis in 8, and premature menopause in 8 women. AD was found in seven relatives, alopecia in six and celiac disease in five. Other conditions were rare. Significant correlation was noticed between the number of autoimmune conditions in AD proband and the number of affected relatives (P = 0.031). A total of 66.4% of people with AD had a first-degree relative suffering from autoimmunity. Autoimmune conditions were more frequent among females: sisters (P < 0.001), mothers (P = 0.002) and grandmothers (P = 0.002). CONCLUSIONS: Considerable prevalence of autoimmune conditions in relatives of people with AD confirms substantial risk of autoimmunity, especially in females and relatives of patients affected by multiplex autoimmunity. Our data corroborate the recommendation of active screening for autoimmune disorders, particularly thyroid disease, among AD family members.

Increased risk of endocrine autoimmunity in first-degree relatives of patients with autoimmune Addison's disease.

OBJECTIVE: Autoimmune conditions tend to cluster in subjects with Addison's disease (AD) and probably also among their relatives. The aim of the study was to estimate the frequency of the endocrine gland-specific autoantibodies in first-degree relatives of patients with AD. METHODS: Autoantibodies were investigated in 113 family members using RIA and ELISA assays. The control group comprised 143 age-matched volunteers. RESULTS: Autoimmune diseases were diagnosed in 38.1% relatives. Hashimoto's thyroiditis was found in 20.3%, Graves' disease in 8.0%, vitiligo and type 1 diabetes in 3.5%, whereas AD, rheumatoid arthritis and atrophic gastritis with pernicious anaemia in 2.7% each. All studied antibodies except for islet antigen-2 (P = 0.085) were significantly more frequent in AD relatives than in controls (P < 0.05). Antibodies to 21-hydroxylase were detected in 6.2% relatives, thyroid peroxidase in 28.3%, thyroglobulin in 19.5%, glutamic acid decarboxylase in 8.0%, and zinc transporter-8 in 7.1%. Two and more autoantibodies were detected in 18.6% subjects. Significant gender difference was revealed only for aTPO, more common in female relatives (P = 0.014; OR: 3.16; 95% CI: 1.23-8.12). Circulating autoantibodies were found more frequently in the relatives of affected males (P = 0.008; OR: 3.31; 95% CI: 1.33-8.23), and in family members of patients with polyendocrine autoimmunity (P = 0.009; OR: 3.55; 95% CI: 1.31-9.57). CONCLUSIONS: This study provides evidence of increased susceptibility for the endocrine autoimmunity, especially thyroid disease, in close relatives of patients with AD. Relatives of the male AD patients and of those with autoimmune polyendocrine syndrome are at particular risk and should undergo periodic screening for autoimmune endocrine disorders.