Mrs. Ishikawa was the wife of Hiro Ishikawa, the mother of Keiko O'Brien, and the grandmother of Molly O'Brien and Kirayoshi O'Brien. She was born in 2269.

Miles and Keiko O'Brien went to Earth in 2369 to celebrate Mrs. Ishikawa's one-hundredth birthday. (DS9: "Dax")

Keiko's mother is unnamed. Her last name comes from Keiko's maiden name in TNG: "Data's Day". Her birthdate comes from a line Sisko's log about Miles O'Brien and his wife visiting Earth for her mother's 100th birthday in DS9: "Dax". In the original script for "Dax", it is her funeral, not birthday, the couple is attending. [1]