A precocious blond moppet of television fame who graduated to features upon adolescence, Brian Bonsall made his first impact as Andrew Keaton, the adorable little brother of Michael J Fox, during the last three seasons (1986-89) of the hit NBC sitcom "Family Ties. " So cute as to tug at maternal heartstrings, he proved a natural for issue-oriented TV movies about such subjects as juvenile AIDS like "Go Toward the Light" (CBS, 1988) and child molestation with "Do You Know the Muffin Man?" (CBS, 1989). Bonsall's credits include various TV specials and series guest spots. Under heavy make-up, he portrayed the Klingon youth Alexander, the son of Worf, on the syndicated "Star Trek: The Next Generation." In his feature debut, "Mikey" (1992), Bonsall was improbably cast as a psychotic kid who murders a succession of foster families. He reverted to type as the innocent son of Patrick Swayze in "Father Hood" (1993).