Have you looked at this? http://www.educationaloptions.com/levels_giftedness.htm

My recollections of DD at 2.5 are a little hazy. At that age she couldn't get enough of being read to. She was verbal very early. She was able to draw a large capital E with crayon on paper. At age 3.5, she announced to her grandparents that she would "now do an interpretive dance". She then performed a dance to show a seed sprouting and blooming into a flower. She could recite "The Night Before Christmas". Just before she turned four, she begged me to teach her to read. She picked it up very quickly and has had her nose buried in books ever since. Her WISC scores at age 8: GAI~MG, VCI~HG. Her FSIQ is not valid due to a visual/motor integration problem.

At 2.5, DS knew all the letters and letter sounds and was just beginning to sound out words like CAT, BUG, etc. He was beginning to add and subtract and could count to at least 30. His reading and math skills have developed a full year (or more) earlier than DD's. His WPPSI-III score at age 4.5: FSIQ~EG.

For my definitions of MG, HG, EG, PG, I'm going by this chart:

http://www.hoagiesgifted.org/highly_profoundly.htm