Despite the facts that their biochemical and bone abnormalities had normalised and that the children no longer had significantly elevated PTH, 1,25(OH)2D, C-FGF23 or TALP concentrations or visible signs of bone deformities, 25OHD-t1/2 in children with a history of rickets was ∼7 days shorter than that in the local community children, suggestive of a long-standing increased expenditure of 25OHD. This evidence concerns the gene PTH and rickets.