To verify these conclusions, they generated mammalian expression constructs carrying three different lengths of the normal HTRA1 promoter (WT-long, -medium, and -short) and the mutant sequence carrying the AMD-risk allele at the single nucleotide polymorphism (SNP) rs11200638 (SNP-long and -medium), and these constructs were transfected into human embryonic kidney293 (HEK293), human-derived retinal pigment epithelial (ARPE19), and Human retinoblastoma (Y79) cells. Here, HTRA1 is linked to retinoblastoma.