Multiple evidence strands suggest that there may be as few as 19,000 human protein-coding genes
Human Molecular Genetics (2014) - Comments
pubmed: 24939910  doi: 10.1093/hmg/ddu309  issn: 1460-2083  issn: 0964-6906 

Iakes Ezkurdia, David Juan, Jose Manuel Rodriguez, Adam Frankish, Mark Diekhans, Jennifer Harrow, Jesus Vazquez, Alfonso Valencia, Michael L. Tress