There is no certainty in these matters, but the fact that your grandmother and great grandmother had it probably increases your chances of getting it too.
Your grandmother's mother is your great grandmother.
Your grandmother's mother is your great grandmother.
Answer: We would call Her your "Great Grandmother" ~ 1)your Moma's Mother would be your Grandma or GrandMother. 2) your Grandmother's Mother is your Great-Grandma or Great-Grandmother .. {1) you are your Mother's Child. 2) You are your Grandmother's Grandchild , and you are the Great Grandchild of your Great Grandmother....
Your grandmother's mother would be your great-grandmother.
Your grandmother's mother would be your great-grandmother.
Your grandmother's brother is your great uncle.
Your grandmother's mother would be your great-grandmother.
You and the granddaughter of your grandmother's brothers, and sisters, are first cousins.
Your grandmother's sister is your great aunt.
Your grandmother's brother is your great uncle.
Your great great grandmother's sister is your great great grandaunt, some would say great great greataunt.
You would say "oumagrootjie" in Afrikaans to refer to your great grandmother.