Sledge was found unresponsive at her home in Phoenix on Friday and the cause of death has not been determined, according to a statement from the band's publicists.
The family of the 70s disco icon said in a statement: "On yesterday, numbness fell upon our family".
Sledge and sisters Debbie, Kim and Kathy formed Sister Sledge in 1971, but had to wait for the breakout success of We Are Family in 1979, when Atlantic Records teamed the little-known act with up-and-coming hitmakers Bernard Edwards and Nile Rodgers. "We were saying: "Well, maybe we should go to college and just become lawyers or something other than music, because it really is tough", she said. Sister Sledge is most notable for their enduring and hit dance song "We Are Family." .
South Korean President Park Geun-hye Removed From Office
Two people were killed in protests with riot police, while a third elderly man had a heart attack and died on Saturday. The decision led crowds to break out in elation (among anti-Park camps) and emotion (among Park supporters).
Joni Sledge was born September 13, 1956, to tap dancer Edwin Sledge and actress Florez Sledge.
The song celebrating sisterhood and female empowerment was nominated for a Grammy and sold more than one million copies, as did the album of the same name.
Sledge is survived by an adult son and her sisters.
Daylight Saving Time: Clocks 'Spring Forward' One Hour Tonight
Previously, Canada had observed Daylight Saving Time from the first Sunday in April until the last Sunday in October. At 2 a.m. on Sunday, you will lose an hour or spring forward an hour and the correct time will be 3 a.m.
Joni's website says her "extraordinary talent has been developed within the illustrious backdrop of her family legacy; Grand mother, Viola Beatrix Hairston Williams, (Julliard graduate and lyric soprano), was a dedicated coach".
The daughter of Broadway tap dancer, Edwin Sledge and actress Florez Sledge, Joni was the second oldest of the four sisters. But the trio of sisters continued to record and tour into the present, including a 2015 performance for Pope Francis. Her award-winning work has appeared in numerous magazine, newspaper, and online publications.
Daylight Saving Time 2017: What to know, when to spring forward
The idea of daylight saving was the brainchild of Benjamin Franklin, aka, the "early to bed, early to rise" guy, back in 1784. He says most of us are already sleep-deprived, getting between five and 10 hours of sleep less than we should each week.