These are all the transcripts for NRXN1 in hg19 that are associated with a UniProt protein as of Ensembl, see https://grch37.ensembl.org/Homo_sapiens/Gene/Summary?db=core;g=ENSG00000179915;r=2:50145643-51259674;t=ENST00000404971.
All unique exons are annotated in the table unique_exons.txt.