TGFB1 and keloid: For instance, several polymorphisms in the TGFβ1 gene, such as -988C/A, -800G/A and -509C/T in the promoter region, and the mutations like Arg25Pro and Leu10Pro in exon 1, as well as Thr263Ile in exon 5, have been shown to predispose individuals to keloids [18].