Absence of Heterozygous K83E and R257X Mutations of the AIRE-1 Gene in 46 Children with Type 1 Diabetes and 44 Children with Graves’ Disease

Type 1 diabetes mellitus (DM) and Graves' disease are autoimmune diseases, and a number of genetic factors, including HLA and CTLA-4 genes, have been reported to contribute to their etiology. The gene responsible for autoimmune polyendocrinopathy- candidiasis-ectodermal dystrophy (APECED) has been cloned and named the autoimmune regulator-1 (AIRE-1) gene. AIRE-1 protein is thought to be a transcription regulatory protein and to have a role in the maintenance of immunological tolerance. The aim of this study was to determine whether heterozygous AIRE-1 gene mutations are associated with childhood-onset type 1 diabetes and Graves' disease in the Japanese population. We investigated 46 children with type 1 DM (29 females and 17 males; age at the time of diagnosis, 0.5-16 yr) and 44 children with Graves' disease (34 females and 10 males; age at the time of diagnosis, 3-16 yr) for the presence of the K83E mutation in exon 2 and the R257X mutation in exon 6 of the AIRE-1 gene. The alleles were identified by polymerase chain reaction of genomic DNA and restriction fragment-length polymorphism analysis (PCR-RFLP) with endonuclease TaqI. Since no patients with type 1 DM or Graves' disease were found to carry the K83E or the R257X heterozygous mutation, we concluded that neither the K83E nor the R257X heterozygous mutation in the AIRE-1 gene seem to be the cause of the more common isolated endocrinopathies, i.e., type 1 diabetes mellitus and Graves' disease, in Japanese children.