As far as I know, both Wanda and Pietro aren't mutants anymore (and actually never were), instead they were revealed to be experiments conducted by the High Evolutionary in Uncanny Avengers #4 (2015):
In fact, House of X #4 (2019) explicitly lists her as a non-mutant:
LOOK AT WHAT THEY’VE DONE
MUTANT EXTINCTION EVENTS [...]
DECIMATION: MUTANT ...