DBH
The DBH gene encodes for an enzyme in the body that converts dopamine to norepinephrine. Excessive levels are associated with restlessness and anxiety due to the loss of dopamine and the increase in norepinephrine. DBH shows variability by ABO blood type, being much more active in those with blood type O. DBH activity can be modulated with regular exercise, a higher protein diet, and a low-wheat diet. The supplement pantethine, vitamin C, and fasting have been shown to help modulate DBH activity.
Personality trait research has found that high activity DBH (i.e. increased norepinephrine) is associated with impulsiveness trait while low activity DBH is associated with sensation-seeking.
There was a significantly greater cocaine use rate among patients who were homozygous for the higher activity C allele (CC) at rs1611115. It appears that lower DBH activity helps potentiate the inhibitory effects of doxazosin on DBH in the treatment of cocaine use disorder (CUD) [29498170].
Diseases associated with decreased DBH activity: early-stage Alzheimer's, ADHD, autism, bipolar with more depression, Down syndrome, hyperthyroidism, Parkinson's, and unipolar depression.
Diseases associated with INCREASED DBH activity: late-stage Alzheimer's, bipolar with more mania, Huntington's, hypothyroid, IBD, major depressive disorder (MDD), PTSD.
References:
1. Hess C, Reif A, Strobel A, Boreatti-Hümmer A, Heine M, Lesch KP, Jacob CP. A functional dopamine-beta-hydroxylase gene promoter polymorphism is associated with impulsive personality styles, but not with affective disorders. J Neural Transm (Vienna). 2009 Feb;116(2):121-30. doi: 10.1007/s00702-008-0138-0. PubMed PMID: 18982239.
2. Wilson AF, Elston RC, Siervogel RM, Tran LD. Linkage of a gene regulating dopamine-beta-hydroxylase activity and the ABO blood group locus. Am J Hum Genet. 1988 Jan;42(1):160-6. PubMed PMID: 3422127; PubMed Central PMCID: PMC1715334.
3. Xing C, Torres-Caban M, Wang T, Lu Q, Xing G, Elston RC. Linkage studies of catechol-O-methyltransferase (COMT) and dopamine-beta-hydroxylase (DBH) cDNA expression levels. BMC Proc. 2007;1 Suppl 1:S95. PubMed PMID: 18466599; PubMed Central PMCID: PMC2367604.
