A new syndrome: multiple dislocations of distal interphalangeal joints associated with interstitial pneumonia, Sjögren's syndrome, and positive autoantibodies.

Abstract  A 54-year-old woman and a 64-year-old man consulted our clinic for dislocation of the distal interphalangeal (DIP) joints. They both had been diagnosed as having Sjögren's syndrome. In addition, interstitial pneumonia had been detected several years earlier in both cases. Antibodies to SSA/Ro (52 kDa) and Jo-1 were detected in their sera, but serum CK and aldolase levels were normal. There were no eruptions, and muscle strength was normal in both patients. The combination of the following six conditions, i.e., (1) multiple dislocations of DIP joints, (2) interstitial pneumonia, (3) Sjögren's syndrome, (4) positive anti-SSA antibodies (52 kDa), (5) positive anti-Jo-1 autoantibodies, and (6) children with hypermobile joints is quite rare and not observed frequently. Existence of the above six conditions in two patients is even rarer. Therefore, the probability that all six conditions would coincidentally coexist in each of the two separate subjects is virtually zero. In this article, we propose a novel clinical complex - multiple dislocations of DIP joints, interstitial pneumonia associated with Sjögren's syndrome, and positive anti-SSA and anti-Jo-1 antibodies (DIPSSJ) - as a new syndrome of which clinicians should be aware. Because the children of both patients had hypermobile joints, the syndrome may be partially genetic.