A prior GWAS study showed that the SNP variant rs10914144 located within the second intron of the DNM3 gene locus is associated with variation in human platelet volume. The study by Nürnberg et al shows that a second SNP variant (rs2038479), which is in high linkage disequilibrium with rs10914144, marks a megakaryocyte-specific alternate promoter. This promoter binds the Mk transcription factors MEIS1/RUNX1 and produces a shortened DNM3 transcript. The minor alleles (“C” for rs2038479 and “T” for rs10914144) are associated with decreased expression of the alternate transcript and smaller platelet size. Repressive factors are postulated to bind to the rs2038479 minor allele to a greater extent than the major allele. See Figure 6 in the article by Nürnberg et al that begins on page 4859.