Bone involvement in monogenic autoinflammatory syndromes
Until recently the most common autoinflammatory diseases (AIDs) associated with bone disease in childhood included a few genetically complex (chronic non-bacterial osteomyelitis, synovitis, acne, pustulosis, hyperostosis and osteitis syndrome) and monogenic (Majeed syndrome, deficiency of IL-1 receptor antagonist, cherubism) AIDs. However, the spectrum of monogenic AIDs associated with bone manifestations has markedly expanded to include both recently identified diseases such as the type I interferonopathies and also newly recognized bone dysplasias in already established AIDs. In addition, we propose that some known bone dysplasia syndromes, especially those presenting with hyperostosis and associated systemic inflammation, be classified as AIDs. Collectively, we provide an overview of the diverse bone manifestations identified in the genetically defined AIDs, discuss the hypotheses of the underlying pathophysiological mechanisms and highlight potential novel therapeutic strategies.