COMPENDIUM ON FUNCTIONAL MEDICINE - Flipbook - Page 210
● Depends on methyl donors and proper methylation function
Key HNMT Variants:
HNMT rs11558538 (C314T)
Also known as Thr105Ile, this SNP changes the amino acid at
position 105 from threonine to isoleucine, with frequencies of
approximately 90% for Thr105 and 10% for Ile105. The Ile105 allele
correlates with diminished HNMT enzyme activity, which can result
in reduced histamine inactivation and increased sensitivity to
histamine [29].
HNMT rs1050891
Located in the 3' untranslated region, may affect HNMT expression
and function.
Histamine Resistance and Sensitivity: While there isn't a specific
"histamine resistance" gene per se, variations in histamine
metabolism genes create a spectrum of individual responses to
histamine:
1. Low DAO Activity: Individuals with SNPs reducing DAO
activity may experience histamine intolerance symptoms
even with normal histamine intake [28].
2. Low HNMT Activity: Those with reduced HNMT function
may have impaired ability to process histamine in the central
nervous system, potentially contributing to neurological and
psychological symptoms [30].
3. High Metabolism Function: On the other end of the
spectrum, some individuals may have highly efficient
histamine processing due to optimal enzyme function,
allowing them to tolerate higher levels of dietary histamine
without adverse effects [31].
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