This paper implicates this snp as playing a role in heart disease.
Having a G at this position is considered normal.
Having an A at this position reduces the risk of heart disease. Approximate 15% of all people carry this allele.
Technical note: This applies to many other snps, but here is the first clean case I've encountered.
dbsnp shows ss3839 and ss16241517 are being read 'fwd' ss16940640 and ss44449258 are being read in 'rev'.
This has C/T alleles when read forward, and A/G when read in reverse. Since the authors of the paper above describe this as an A/G snp, it seems they are reading in reverse. Often papers include even less information, and can leave some ambiguity about these important details.
[PMID 19706030] Validation Study of Genetic Associations with Coronary Artery Disease on Chromosome 3q13-21 and Potential Effect Modification by Smoking
[PMID 19864173] Association study of GATA-2 transcription factor gene (GATA2) polymorphism and Parkinson's disease
[PMID 16934006] GATA2 is associated with familial early-onset coronary artery disease.