The association of HL-A B27 with Forestier's disease (vertebral ankylosing hyperostosis).

Despite the lack of apophyseal or sacroiliac joint involvement, Forestier's disease (vertebral ankylosing hyperostosis) shares with the inflammatory forms of spondylitis, the roentgenographic appearance of spinal new bone formation. Because of this apparent similarity, the prevalence of the HL-A B27 antigen was determined in 47 white patients with Forestier's disease. Sixteen of the patients (34 per cent) possessed the B27 antigen (P is less than 0.001). The mere presence of B27 therefore, does not confirm the diagnosis of inflammatory spondylitis in all patients with roentgenographic evidence of osseous bridging. Applying available epidemiologic information, these data further suggest that patients with the B27 antigen may be at substantial risk of developing Forestier's disease. As Forestier's disease and virtually all of the other B27 associated arthropathies manifest abundant new bone, an association may exist between this antigen and genes controlling new bone formation.