In 1985, at age 22, Garry Kasparov became the youngest world champion of this
[DOC] [TLE] Golden child aged 18 becomes youngest-ever world champion ... [PAR] Jan 24, 2002 ... Ruslan Ponomariov became the youngest ever world champion in ... a record set 
by Garry Kasparov, who won his first title aged 22 in 1985.