GTF2I and Werner syndrome: Although single gene mutation of those 25–27 genes only causes partial phenotypes of WS, genotype-phenotype relationship analysis suggests that GTF2IRD1, GTF2I, BAZ1B, VPS37D, STX1A, CLIP2, LIMK1, MLXIPL, and ELN could be the key genes for the phenotypes (Kozel et al., 2021; Lek et al., 2016).