Autoantibodies against Aromatic l-Amino Acid Decarboxylase Identifies a Subgroup of Patients with Addison’s Disease1

• Published in: The journal of clinical endocrinology and metabolism 2000-01, Vol.85 (1), p.460-463
• Main Authors: Söderbergh, Annika, Rorsman, Fredrik, Halonen, Maria, Ekwall, Olov, Björses, Petra, Kämpe, Olle, Husebye, Eystein S.
• Format: Article
• Language: English
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jcem.85.1.6266

Autoantibodies against aromatic l-amino acid decarboxylase (AADC) are present in about 50 percent of sera from patients with autoimmune polyendocrine syndrome type I (APS I) but absent in sera from patients with different organ-specific autoimmune diseases, such as insulin-dependent diabetes mellitus, Hashimoto’s thyroiditis, and Graves’ disease. AADC is expressed in the pancreatic β-cells, the liver, and the nervous system; and the presence of AADC antibodies has been shown to correlate to hepatitis and vitiligo in APS I patients. Among 101 investigated patients with autoimmune Addison’s disease, 15 had high titers of AADC antibodies. According to the clinical characteristics of these patients, only 3 had APS I. The remaining 12 had either isolated Addison’s disease or associated diabetes mellitus, hypothyroidism, vitiligo, alopecia, gonadal failure, and pernicious anemia. Autoantibodies against 21-hydroxylase were present in 9 of 12, whereas autoantibodies against side-chain cleavage enzyme and 17α-hydroxylase were present in 3 of 12. Two patients had only autoantibodies against AADC. DNA was available from 3 of these 12 patients. One of the patients, a woman with Addison’s disease, autoimmune thyroiditis, and premature menopause was heterozygous for a point mutation (G1021A, Val301Met) in the first plant homeodomain zinc finger domain of the autoimmune regulator (AIRE) gene. The presence of AADC autoantibodies identifies patients with APS I and a subgroup of Addison patients who may have a milder atypical form of APS I or represent a distinct entity. Measurement of autoantibodies against AADC should be included in the evaluation of Addison’s disease.