Madeline had a very noticeable coloboma in her eye iris. This woman does not. Those do not just go away.
https://www.msn.com/en-us/news/other/madeleine-mccann-case-arkansas-woman-claims-she-is-the-missing-girl-and-insists-she-has-dna-proof-in-bizarre-twist/ar-AA2euqG7