CSN2 and coronary artery disorder: The interest in differentiating between A1 and A2 beta-casein (β-CN) in milk dates to the early 1990s, subsequent to hypotheses positing that the β-CN variant in some bovine milk includes a peptide linked to an elevated risk of developing diseases such as type 1 diabetes mellitus (DM-1) and coronary heart disease (CHD) [1,2,3,4].