To investigate estrogen receptor (ER) microsatellite allele frequencies in patients with rheumatoid arthritis (RA), and possible associations of ER microsatellites with osteoporosis and disease progression.
We typed 144 Japanese females with RA and 200 healthy postmenopausal Japanese controls for ER microsatellites by polymerase chain reaction methods using fluorescent labeled primer and semiautomatic genotyping. Bone mineral density (BMD) of patients was measured in the spine by dual energy x-ray absorptiometry, and recent radiographs of the hands and wrists were scored according to the method described by Sharp, et al.
The ER genotype was classified according to number of dinucleotide (thymine-adenine, TA) repeats between 10 and 27. The frequency of allele 14 (14 repeats of TA) was significantly increased in patients versus controls. No association of ER microsatellites with osteoporosis or radiographic progression in the RA patients was noted.
These results suggest that a genetic variation at the ER locus may be associated with other pathogenetic factors in patients with rheumatoid arthritis, but not with BMD and disease aggressiveness.