The eldest daughter of country legend Loretta Lynn has passed away. Betty Sue Lynn died at her home in Waverly, Tenn. on Monday (July 29). She was 64.

Loretta Lynn married her husband, Oliver, when she was just 15 years old. The couple had six children. They lost their oldest son, Jack Benny Lynn, in 1984 at the age of 34.

According to Nashville's News Channel 5, complications from emphysema caused Betty Sue Lynn's death. She is survived by her sister, Clara Marie; brother, Ernest Ray; twin sisters, Peggy and Patsy; daughters Lynn Markworth and Audrey Dyer, and five grandchildren.

A statement from Loretta Lynn's publicist says, "Loretta and her family thank friends and fans for their thoughts and prayers during this time of great loss."

No funeral plans have been announced.