Joni Sledge, who...

...along with her three sisters formed the disco-era family quartet Sister Sledge, died at age 60.

Younger sports fans may be surprised to read (all emphasis mine):

In 1979, Sister Sledge gained mainstream success with the hit album “We Are Family,” which included the single by the same name, which was adopted by the 1979 world champion Pittsburgh Pirates as their theme song, and has endured as a disco anthem. Its memorable chorus — “We are family/I got all my sisters with me” — reflected the group’s wholesome message of togetherness, and the song shot up the single charts, peaking at No. 2.

But, ironically:

When Sister Sledge performed for Pope Francis in 2015 in Philadelphia, Kathy was absent. She said her sisters refused to let her participate, and in a statement released on her behalf, she blamed a “familial dispute that has long been developing between the sisters.”