Matthew
Matthew was a genetically-engineered Human child, born in 2356, who lived in the Genome colony on Moab IV during the 2360s.
Matthew performed Chopin's Prelude Number 4 (which is called "Suffocation", and was probably chosen to be played due to the threat Matthew and his planet faced) on the piano during an outdoor concert for the Genome colonists and the visiting crew of the USS Enterprise-D in mid-2368.
During the concert, Matthew was briefly interrupted by an earthquake, but was encouraged to play on by the colony's leader, Aaron Conor. (TNG: "The Masterpiece Society")
Matthew was played by featured actor Daniel Fawcett.
While named in dialogue, he was simply described in the script as a "12-year-old pianist". The call sheet is listing him as "musician".