Maternal age influences risk for HLA-B27 associated ankylosing enthesopathy in transgenic mice.

Objective-To study further the temporal clustering of ankylosing enthesopathy (AE) noted originally during a study of the influence of mouse major histocompatibility complex (MHC) H-2 and transgenic HLA-B27 on the frequency of AE. Methods-The relationship between maternal age at littering and frequency of AE was analysed. Results-Mice born to mothers aged eight months or older had a significantly lower disease frequency of AE than mice born to mothers younger than eight months of age. This phenomenon was observed in three independent cohorts evaluated to date (p < 0.01, 0.025, and 0.05). Conclusion-Maternal age is a novel, nongenetic risk factor as defined in relation to an MHC associated enthesopathy. Its mode of action and relevance to human disease require further investigation.