Richard Robinson wrote:

I would like to know what is known about Ranma's family history. for
example do his grandparents ( from either side) appear in the cannon.?

Nope.  (Note in the manga.)

I have read that he claims to descended from Samurai, is this in the
cannon or is this just a fanfic legend?

There's no such claim in the manga AFAIK (and my knowledge is
comprehensive but not absolute).

--
David Eddy - Senior Consultant, Progress Software Melbourne
dje@progress.com

Screening Coordinator and Subbing Bunny, Melbourne Anime Society
My fanfics are archived at http://nabiki.newberry.edu/DEddy