A new molecular marker may help to distinguish between systemic onset juvenile idiopathic arthritis (JIA) and other causes of ‘fever of unknown origin’ (FUO) in children. S100A12 is a calcium-binding proinflammatory protein secreted by activated phagocytes and mainly expressed in granulocytes. A study in Germany, the Netherlands, and the USA (Arthritis and Rheumatism 2008;58:3924–31) has shown that serum concentrations of this marker (measured by enzyme-linked immunosorbent assay) are very high in systemic onset JIA (and in familial Mediterranean fever) but not in other main causes of FUO. The study included 240 patients with systemic onset JIA, 17 with familial Mediterranean fever, 83 with systemic infections, 80 with other causes of FUO, and 45 healthy controls. Mean serum concentrations of S100A12 were 7190 ng/ml in systemic- onset JIA, 6720 in familial Mediterranean fever, 470 in systemic infections, 45-720 in other causes of FUO, and 50 ng/ml in the controls. In distinguishing between systemic-onset JIA and infections S100A12 concentration was 66% sensitive and 94% specific.

People who have conduct problems such as severe disobedience, lying, truancy, and unresponsiveness to discipline as adolescents are likely to have social and health problems in later life. From a British birth cohort (all babies born in one week in 1946) a total of …