DEFICIENCY OF A PARATHYROID-HORMONE FRAGMENT CONTAINING THE MIDPORTION AND 1,25-DIHYDROXYVITAMIN-D IN SERUM OF PATIENTS WITH SLIPPED CAPITAL FEMORAL EPIPHYSIS

The endocrine abnormality that causes slipped capital femoral epiphysi s (SCFE) has not been revealed. Recent studies have shown that parathy roid hormone (PTH) and 1,25-dihydroxyvitamin D [1,25-(OH)(2)D] are inv olved in growth-plate chondrogenesis and matrix mineralization. Thus w e examined in 13 patients with SCFE the serum levels of three immunore active forms of PTH (iPTH): the whole peptide [(1-84)PTH], the fragmen t containing the COOH-terminal portion (C-PTH), and the midportion (M- PTH). Additionally, serum levels of 25-hydroxyvitamin D [25-(OH)D] and 1,25-(OH)(2)D were measured. We found that the levels of M-PTH were s ignificantly lower than those of controls, whereas levels of C-PTH and (1-84)PTH were not significantly different from those of controls. Si milarly, levels of 1,25-(OH)(2)D were also significantly lower than co ntrol levels. In patients with initially low levels of M-PTH and 1,25- (OH)(2)D in whom the levels were monitored over a period, all levers r eturned to normal within a year after the onset of disease. The defici ency of M-PTH or 1,25-(OH)(2)D during the growth spurt could result in SCFE, although in this study, we cannot deny the possibility that the slippage may cause the deficiency.