ABO Blood Group Association with DBH, COMT, MAOA, and ACE: Additive Effects, Diversity & Stability in Human Populations
Published on: 2018-09-20
ABO blood groups have distinctive population frequency distributions that show stratification of health risks and behavioral traits. Further, this Mendelian trait can be a useful tool to study how additive effects with many other Mendelian traits produce stratification of populations as to risks of disease and of personality traits. For example, via linkage disequilibrium at the ABO/DBH loci at chromosome 9q34, ABO blood group A can be seen to be associated with high activity dopamine beta hydroxylase (DBH). ABO blood group A may also be associated with high activity catechol-O-methyl transferase (COMT). Hapmap population frequencies for these related gene alleles are congruent with this association of behavior and health. And ABO O association with MAOA low activity is seen from analysis of hapmap population frequencies and associated health risks. Also ACE has shown association with ABO blood groups with ABO A showing low levels ACE, ABO O showing moderate levels of ACE and ABO B showing high levels of ACE, the mechanism thought to be related to differential degradation of ACE enzyme from various ABO antigens that the ACE enzyme expresses. Based on population frequencies of the ACE alleles and population frequencies of the ABO alleles, it appears that individuals with high activity ACE alleles may have ABO alleles that lower activity of ACE so additive effects in this case may counterbalance against extreme ACE enzyme levels. But the end result is that instead of being fairly uniform as to health and personality effects of dopamine levels and activities, populations are stratified as to levels of and activities of dopamine and all the stratification effects on health and behavior produced by that stratification. ABO blood groups were the first genetically based traits studied in the laboratory for association with other traits and genes.This body of work exemplifies the lack of randomness in the association of genes and urges further efforts to understand the evolutionary forces behind this. But at the present time, since ABO phenotype is clinically readily available, these associations can be used to clinically assess the activities of the neurotransmitter enzymes and thus shed light on the individual patient’s health risks as well as on evolutionary implications of these risks.