Gregory R. Andorfer's remarkable communicative skills lay in the subtle blink of an eye, a certain smile.

Born with a degenerative muscle disease, the 13-year-old dismissed limitations and filled his days with discovery and conquest.

"For a little kid with no muscles, he taught me what real strength was," said his father, Gregory P. Andorfer.

Gregory died in Baltimore Tuesday from complications of arthrogryposis.

In the last days of his life, Gregory "pulled this family together in a way I can't really describe," said Mr. Andorfer, executive director of the Maryland Science Center. "He couldn't talk or move major portions of his body, but he would communicate with us by smiling, yelling, laughing, blinking his eyes."

A Pittsburgh native, Gregory attended the Pittsburgh Rehabilitation Institute until he moved with his family to Baltimore in 1997. Here, he attended the William S. Baer School for multiple-handicapped children.

Shari Johnson, principal of the school, recalled watching Gregory exercise in the institution's therapeutic pool.

"Not only was it hard work for him, but no matter how he felt, he always wanted to work with us," Ms. Johnson said. "He would cooperate as hard as he could. At the end, he was able to move more easily and was just as happy as could be.

"He was a child who always had a smile on his face, no matter how much pain or discomfort he was in."

Gregory enjoyed watching movies, listening to music, visiting Disney World and Epcot Center in Orlando, Fla., and being taken skating in his all-terrain stroller.

A funeral Mass will be offered at noon today at the Roman Catholic Cathedral of Mary Our Queen, 5300 N. Charles St.

Contributions may be made in Gregory Andorfer's name to the William S. Baer School, 2001 N. Warwick Ave., Baltimore 21216.

In addition to his father, he is survived by his mother, Beverly Joan Andorfer; a sister, Alexandra Andorfer; and his grandparents, Sophia and Robert Andorfer of Bradenton, Fla., and Helen Heckman of Naselle, Wash.