CDKN1A and progeroid syndrome: Further analysis in proliferative HGPS fibroblasts with the depletion of Δ133p53α isoforms was associated with increased mRNA expression of p53 target genes associated with cellular senescence (p21/CDKN1A), senescence-associated secretory phenotype (SASP) and pro-inflammatory cytokines (IL-6 and IL-8), hence explaining the progeria phenotype [58].