These genes are from GENCODE v33 (maybe they are not valid for any other annotation).
These data can be downloaded here in TSV format.
For more information about these Functional Isoforms, read the following publication:
The clinical importance of tandem exon duplication-derived substitutions.Nucleic Acids Res. 2021 49:8232–46.
Martinez Gomez L, Pozo F, Walsh TA, Abascal F, Tress ML.
DOI:10.1093/nar/gkab623