Table 1: Common phenotypic variants of DBP and associated characteristics.

Phenotypers7041 (D432E)rs4588 (T436K)DBP levels in homozygotes25(OH) D affinity

GC1Ft (D: asp)c (T: thr)LowestHighest
GC1Sg (E: glu)c (T: thr)HighestIntermediate
GC2t (D: asp)a (K: lys)IntermediateLowest

The three most widely studied variants of DBP include GC1F, GC1S, and GC2, which are distinguished by their SNPs rs7041 and rs4588. The associated nucleotide and amino acid changes are presented, along with known data on DBP levels in homozygotes and affinity for 25(OH) D (derived from Powe et al. [9] and Arnaud and Constans [7]). Conflicting data regarding these relationships remain [10].