Author(s)

Kanako Watanabe, Hiromi Sato, Ayano Ito, Tomomi Sato, Aránzazu González-Canga, Hana Sugai, Masahiko Suzuki, Takao Namiki, Koichi Ueno

Assessment Area, Medicines for Veterinary Use Department, Agencia Espa?ola de Medicamentosy Productos Sanitarios (AEMPS), Madrid, Spain.
Department of Frontier Japanese-Oriental (Kampo) Medicine, Graduate School of Medicine, Chiba University, Chiba, Japan.
Department of Geriatric Pharmacology and Therapeutics, Graduate School of Pharmaceutical Sciences, Chiba University, Chiba, Japan.
Research Center for Frontier Medical Engineering, Chiba University, Chiba, Japan.

We investigated the influence of the cytosine-adenine (CA) dinucleotide repeat polymorphism in intron 6 of estrogen receptor β (ERβ) gene on rheumatoid arthritis (RA) risk. One hundred and ninety-three RA patients and 77 control subjects with osteoarthritis (OA) were recruited. The CA repeat polymorphism was assayed by a dye-terminator cycle sequencing analysis. No statistically significant difference in the mean number of CA repeats between the RA and OA patients was observed (RA: 21.47, OA: 21.23, P = 0.324). The alleles were categorized according to the number of repeats: short (S, ≦21) and long (L, ≧22), in which the genotypes SS, SL, and LL were observed. No significant differences were observed for the allele and genotype distributions of this polymorphism in both patient groups. The RA patients were classified according to RA severity: mild (least erosive disease) and severe (more erosive and mutilating disease). Again, no significant difference in genotype frequency between these groups was observed, even after stratifying by sex. The present study indicates that additional studies are needed to clarify the roles of this polymorphism, estrogen, and ER in the development of autoimmune diseases.

Polymorphism; Rheumatoid Arthritis; Sex; Estrogen Receptor β; CA Repeat

Watanabe, K. , Sato, H. , Ito, A. , Sato, T. , González-Canga, A. , Sugai, H. , Suzuki, M. , Namiki, T. and Ueno, K. (2013) Association of a cytosine-adenine repeat polymorphism in the estrogen receptor β gene with occurrence and severity of rheumatoid arthritis. Open Journal of Internal Medicine, 3, 3-7. doi: 10.4236/ojim.2013.31002.