New HLA DRB1 and DQB1 haplotypes in a pedigree of familial Graves' disease in Japan.

The present study demonstrated genetic analysis of human leukocyte antigen (HLA) in a familial Graves' disease linked to autoimmune mechanism. The proband was a 17 year-old female. At 15 years, Graves' disease was diagnosed with serum TSH was <0.015 IU/ml; free T(3), 13.6 pg/ml; free T(4), 4.51 ng/dl; and TSH receptor antibody (TRAb), 94.1%. She had two brothers (19 and 13 years-old), who manifested Graves' disease at 18 and 13 years, respectively. They also had elevated TRAb as high as 48.4 and 49.1%, respectively. There was a strong family history of Graves' disease in their maternal pedigree. Namely, their two aunts and a cousin had Graves' disease, and their onset ages of Graves' disease were also during their teen-age years. However, there was no patient with Graves' disease in the paternal pedigree. We checked HLA-DRB and -DQB haplotype in the members of maternal pedigree and proband's father. The members of maternal pedigree including both affected and unaffected Graves' disease had haplotypes of DRB1*150101 and DQB1*0602, except for the cousin who had DRB1*140301 and DQB1*030101. The haplotypes of DRB1*150101 and DQB1*0602 were different from susceptible HLA types in Japanese childhood onset Graves' disease. However, two cases of Graves' disease also had HLA types of DRB1*40501 and DQB1*0401, in addition to the haplotypes of DRB1*150101 and DQB1*0602. There was no other autoimmune disease including type 1 diabetes mellitus in their family. The present findings indicated that familial Graves' disease was found mainly in the maternal females and become overt during their teen-age years. They had new HLA haplotypes distinct from those susceptibly in Japanese Graves' patients. Further study will be necessary to analyze the mutant locus of DNA to elucidate pathogenesis of familial Graves' disease.