Systemic Lupus Erythematosus (SLE) is an autoimmune disease with a very
varied spectrum of clinical manifestations that could be partly
determined by genetic factors. We aimed to determine the relationship
between prevalence of 11 clinical features and age of disease onset with
European population genetic substructure. Data from 1413 patients of
European ancestry recruited in nine countries was tested for association
with genotypes of top ancestry informative markers. This analysis was
done with logistic regression between phenotypes and genotypes or
principal components extracted from them. We used a genetic additive
model and adjusted for gender and disease duration. Three clinical
features showed association with ancestry informative markers:
autoantibody production defined as immunologic disorder (P =
6.8x10(-4)), oral ulcers (P = 6.9x10(-4)) and photosensitivity (P =
0.002). Immunologic disorder was associated with genotypes more common
in Southern European ancestries, whereas the opposite trend was observed
for photosensitivity. Oral ulcers were specifically more common in
patients of Spanish and Portuguese self-reported ancestry. These results
should be taken into account in future research and suggest new
hypotheses and possible underlying mechanisms to be investigated. A
first hypothesis linking photosensitivity with variation in skin
pigmentation is suggested