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J Med Genet 41:e38 doi:10.1136/jmg.2003.009282
  • Electronic letters

DBH gene variants that cause low plasma dopamine β hydroxylase with or without a severe orthostatic syndrome

  1. J Deinum1,
  2. G C H Steenbergen-Spanjers2,
  3. M Jansen2,
  4. F Boomsma3,
  5. J W M Lenders1,
  6. F J van Ittersum4,
  7. N Hück2,
  8. L P van den Heuvel2,
  9. R A Wevers2
  1. 1Department of Medicine, University Medical Center Nijmegen St Radboud, Geert Grooteplein 8, 6525 GA Nijmegen, Netherlands
  2. 2Laboratory of Pediatrics and Neurology, University Medical Center Nijmegen St Radboud, Reinier Postlaan 4, 6500 HB Nijmegen, Netherlands
  3. 3Department of Medicine, Erasmus University Medical Center Rotterdam, Room L 276, Dr. Molewaterplein 40, 3015 GD Rotterdam, Netherlands
  4. 4Department of Nephrology, Vrije Universiteit Medical Center, Amsterdam, De Boelelaan 1117 1081 HV Amsterdam, Netherlands
  1. Correspondence to:
 Dr J Deinum
 Department of Medicine, University Medical Center Nijmegen St Radboud, Geert Grooteplein 8, 6525 GA Nijmegen, Netherlands; e-mail j.deinumaig.umcn.nl
  • Received 7 April 2003
  • Accepted 8 September 2003

The enzyme dopamine β hydroxylase (EC 1.14.17.1, MIM 223360) is a monooxygenase that catalyses the conversion of dopamine to norepinephrine. It requires copper as a cofactor and uses oxygen and ascorbate as cosubstrates.1 Dopamine β hydroxylase is localised within the soluble and membrane fractions of secretory vesicles of neurones of the central nervous system that produce epinephrine and norepinephrine, sympathetic ganglia, and cells of the adrenal medulla.2–4 The soluble form of the enzyme is secreted into the circulation, together with norepinephrine, from nerve terminals.5,6 The major form of this glycosylated enzyme seems to be a tetramer of 290 kD.7 Dopamine β hydroxylase continues to receive much attention because of its importance in the synthesis of catecholamines and, hence, its possible involvement in psychiatric disorders such as depression.

Concentrations of dopamine β hydroxylase in blood vary considerably in the general population, but intra-individual variation is low.8 Some 4% of the population have nearly undetectable plasma concentrations, with normal concentrations of norepinephrine and epinephrine.9 Extremely low plasma concentrations of dopamine β hydroxylase seems to be inherited monogenetically by an autosomal codominant mechanism. Recently, Zabetian et al. provided strong arguments that an allelic variant in the 5′ flanking region (−1021) is the major quantitative trait locus that determines plasma concentrations of dopamine β hydroxylase.10 Absence of dopamine β hydroxylase also has been described in conjunction with nearly undetectable concentrations of norepinephrine and epinephrine, hugely elevated concentrations of dopamine, and a syndrome of sympathetic failure.11–13 This is compatible with defective conversion of dopamine to norepinephrine by dopamine β hydroxylase, and it therefore can be designated as dopamine β hydroxylase deficiency syndrome. This phenotype seems to be transmitted as a recessive trait, and it can be treated successfully by administration of L-threo-3,4-dihydroxyphenylserine, which can …