These genes are from GENCODE v33 (maybe they are not valid for any other annotation).
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.