Born in Sacramento, Calif., Robinson's first taste of music came through playing in her high school marching band and singing in her church's choir.
Robinson first collaborated with Sly Stone, whom she met while she was still in high school, when she joined his group The Stoners in 1966. After they disbanded, she and her cousin Larry Graham became members of The Family Stone, which brought together musicians of various races.
Their hits included "Everyday People," "Dance to the Music," "Hot Fun in the Summertime" and "I Want to Take You Higher." After Sly Stone departed the group, Robinson and some of the other musicians continued to record as The Family Stone and released a single called "Do Yo Dance" just this past summer. In 1993, the group was inducted into the Rock 'n' Roll Hall of Fame.
Though Sly and the Family Stone broke up in the mid-'70s, Robinson and Stone continued to record together through the 1980s. They were so close that at one point during the height of the group's popularity, he canceled three months' worth of bookings (including an appearance on The Ed Sullivan Show) to give Robinson time to recover from emergency gall bladder surgery, Rolling Stone reports.
Robinson and Graham also worked together in his band Graham Central Station, and she collaborated with other musicians including George Clinton and Prince.
Robinson is survived by two daughters. The Cynthia Robinson Cancer Care Fund had recently been established to help Robinson's "rising medical costs," the administrator of her Facebook page wrote.