Blood harmane (1-Methyl-9 H -Pyrido[3,4- b ]indole) concentrations in essential tremor: Repeat observation in cases and controls in New York

Elan D. Louis, Wendy Jiang, Marina Gerbin, Amanda S. Viner, Pam Factor-Litvak, Wei Zheng

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Essential tremor (ET) is a widespread late-life neurological disease. Genetic and environmental factors are likely to play important etiological roles. Harmane (1-methyl-9H-pyrido[3,4-b]indole) is a potent tremor-producing neurotoxin. Previously, elevated blood harmane concentrations were demonstrated in ET cases compared to controls, but these observations have all been cross-sectional, assessing each subject at only one time point. Thus, no one has ever repeat-assayed blood harmane in the same subjects twice. Whether the observed case-control difference persists at a second time point, years later, is unknown. The current goal was to reassess a sample of our ET cases and controls to determine whether blood harmane concentration remained elevated in ET at a second time point. Blood harmane concentrations were quantified by a well-established high-performance liquid chromatography method in 63 ET cases and 70 controls. A mean of approximately 6 yr elapsed between the initial and this subsequent blood harmane determination. The mean log blood harmane concentration was significantly higher in cases than controls (0.30 ± 0.61 g-10/ml versus 0.08 ± 0.55 g-10/ml), and the median value in cases was double that of controls: 0.22 g-10/ml versus 0.11 g-10/ml. The log blood harmane concentration was highest in cases with a family history of ET. Blood harmane concentration was elevated in ET cases compared to controls when reassessed at a second time point several years later, indicating what seems to be a stable association between this environmental toxin and ET.

Original languageEnglish (US)
Pages (from-to)673-683
Number of pages11
JournalJournal of Toxicology and Environmental Health - Part A: Current Issues
Issue number12
StatePublished - Jun 15 2012
Externally publishedYes

ASJC Scopus subject areas

  • Toxicology
  • Health, Toxicology and Mutagenesis


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