A second MIF promoter polymorphism comprises a G-to-C single nucleotide polymorphism (SNP) at position -173 (rs755622), which is in strong linkage disequilibrium with -794 7-CATT and is associated with arthritis clinical severity and higher serum and synovial fluid MIF levels.
A significantly lower frequency of the G allele of rs755622 was observed in the oral aphthae, genital ulceration, hypopyon, and arthritis subgroups compared with controls (P(c) < 0.05).