Moreover, the COL1A1 Sp1-binding site was not significantly associated with genital prolapse among our study subjects.24 Another study of particular interest was the finding that the only case of polymorphic homozygosity (TT) of the COL1A1 gene was found in the control group (that is, women without POP), suggesting that the GT genotype has a stronger association with POP than the TT genotype.25 This evidence concerns the gene COL1A1 and pelvic organ prolapse.