DBH gene variants that cause low plasma dopamine β hydroxylase with or without a severe orthostatic syndrome. Issue 4 (1st April 2004) - Deinum, J; Steenbergen-Spanjers, G C H; Jansen, M; Boomsma, F; Lenders, J W M; van Ittersum, F J; Hück, N; van den Heuvel, L P; Wevers, R A