According to codegen.eu I'm a carrier of a Duffy weak allele. For SNP rs34599082 I have alleles C and T. T is a rare allele that found is less thatn ~1% of the population.

Codegen.eu directs me to the article "A homologous naturally occurring mutation in Duffy and CCR5 leading to reduced receptor expression." with the following abstract:

Genetic variations in the CC chemokine receptor (CCR5) leading to reduced or absent expression are associated with resistance to human immunodeficiency virus infection and delayed onset of acquired immunodeficiency syndrome. Similarly, lack of the red-cell chemokine receptor Duffy confers protection against malarial infection by Plasmodium vivax. Investigators have previously described a missense mutation (R89C) in the first intracellular loop of Duffy that results in reduced protein expression. The present study shows that the lower Duffy expression is due to loss of the positive charge at this position, resulting in protein instability. Moreover, R60S, a mutation in the first intracellular loop of CCR5 noted in a recent cohort study, likewise results in reduced surface expression and function of CCR5. The presence of a homologous, naturally occurring mutation that may be protective against disease thus defines a novel mechanism accounting for the decreased expression of these receptors in some individuals.

The description on SNPedia is:

rs34599082, also known as c.265C>T, p.Arg89Cys and R89C, represents an uncommon variant in the DARC gene on chromosome 1, which is better known for it's role as part of the Duffy blood group (antigen) on red blood cells. Found in ~1% of the population, the rs34599082(A) allele (as represented in dbSNP/minus orientation) encodes the Duffy blood group FY(bwk) phenotype, which is also known as FY-weak. This allele results in lower amounts of DARC protein, and thus lower antigen expression and chemokine binding ability. This variant may offer some protection against infection by malaria.

Because polymorphyism in rs34599082 is said to be rare and blood type Fy(a-b-) among Sub-Saharan Africans without Duffy receptor quite common, polymorphyism in rs34599082 couldn't be the cause of blood type Fy(a-b-). It turns out mutation in another SNP rs2814778 is what causes Fy(a-b-) and I don't have it. rs34599082 seems to render blod type Fy(bwk) which isn't the same as Fy(a-b-).

The following questions arises:

  • Are there any health issues related to reduced expression of DARC protein?
  • Just how much am I protected agaisnt malaria by having only one allele?
  • The allele is rare in all populations, but is it possible to say something about where it comes from?

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