Can marrying a a partner who's sibling has a disorder due to cousin marriage increase risk?

Hi, Can marrying someone who's sibling has a disorder be risky in terms of having a child with a disorder in the future? Facts to consider: * Given that her parents were cousins. * Given that my parents are not cousins. * Given that my mother's parents were related and had a child with disorder. * We are not related. * I don't know the particular disorder that her sibling has Appreciate your help! Thanks, Murtaza