Clinical feature: 

Definition: Histamine Intolerance is an intolerance of ingested histamine probably caused by dysfunction of the two metabolizing enzymes HNMT and DAO. The symptoms are similar to allegic reactions.

Literature: 

Aksoy S et al. (1996) Human histamine N-methyltransferase gene: structural characterization and chromosomal location.
Barnes WG et al. (2004) Characterization of a new mRNA species from the human histamine N-methyltransferase gene.
Preuss CV et al. (1998) Human histamine N-methyltransferase pharmacogenetics: common genetic polymorphisms that alter activity.
Price RA et al. (1993) Genetic segregation analysis of red blood cell (RBC) histamine N-methyltransferase (HNMT) activity.
Sasaki Y et al. (2000) Lack of association between atopic asthma and polymorphisms of the histamine H1 receptor, histamine H2 receptor, and histamine N-methyltransferase genes.
Sharma S et al. (2005) Lack of association of histamine-N-methyltransferase (HNMT) polymorphisms with asthma in the Indian population.
Yamauchi K et al. (1994) Structure and function of human histamine N-methyltransferase: critical enzyme in histamine metabolism in airway.
Yan L et al. (2000) Histamine N-methyltransferase pharmacogenetics: association of a common functional polymorphism with asthma.