Objective-In view of the possible role of oestrogens in the pathogenesis of
rheumatoid arthritis (RA), this study investigated the association between
oestrogen receptor (OR) gene polymorphisms and RA.
Methods-Pvu II and Xba I restriction fragment length polymorphisms of the O
R gene were analysed in 70 male and 240 female patients with RA, and in 300
male and 350 female controls. The absence or presence of restriction sites
were represented as P,p (Pvu II) or X, x (Xba I). The distribution of OR g
enotypes was compared between the RA and control subjects by sex. RA patien
ts were divided into subgroups according to their OR genotypes, then the ag
e at onset, seropositivity, and rheumatoid nodule positivity were compared
between the subgroups.
Results-The OR genotype frequency of distribution did not have significant
differences between the male RA and male controls nor between the female RA
and female controls. In women with RA, there was a significant difference
of age at onset between the subgroups (uncorrected p=0.047, corrected p=0.9
4). Female patients with the OR genotype PPxx (homozygote of Px) tended to
have developed RA at a younger age, whereas those with PPXX and ppxx (lack
of Pr haplotype) developed RA at an older age. In men with RA, there was no
association between the OR genotype and age at onset. In seropositivity an
d rheumatoid nodule positivity, there was no significant difference between
subgroups for either sex.
Conclusions-Some variants of the OR gene are related to the onset of RA in
women in certain age periods, suggesting the role of the interaction betwee
n the OR gene and serum concentrations of oestrogen at the onset of the dis