EXHIBIT 10.1 [LEXICON GENETICS LETTERHEAD] February 19, 2003 Dr. Alan S. Nies Dear Alan: We are pleased to invite you to become the Chairman of the Medical Advisory Board of, and a special consultant to, Lexicon Genetics Incorporated (which, together...Consulting Agreement • April 30th, 2004 • Lexicon Genetics Inc/Tx • In vitro & in vivo diagnostic substances • Texas
