Pre-existing medical conditions coverage

[submittedviaemail]

My mum is coming to the US for an extended period of time (>1yr.). She has Lupus and currently has medical insurance in Canada. Is that pre existing or is it like my employment insurance when I came to the US where if I had insurance overlapping then it was not considered pre-existing?

[insubuy]

It would be considered as pre-existing conditions and not covered.