Futaki passed away on May 13 in a Tokyo hospital from an unspecified illness, said The Hollywood Reporter.
She worked for Studio Ghibli for three decades and was an animator for all of legendary Japanese director Hayao Miyazaki's productions including "Howl's Moving Castle", "Princess Mononoke" and 2013's "The Wind Rises". Her final film credit was Hiromasa Yonebayashi's critically acclaimed "When Marnie Was There".
Futaki also worked as a key animator on "Akira", the iconic 1988 Japanese feature adaptation of Katsuhiro Otomo's comic series, which the author directed.