The seipin gene BSCL2 was originally identified in mammals and the fruit fly, and later extended to fungi and plants. The human seipin gene is located on chromosome 11q13, with protein coding on the Crick strand.
There are three validated coding transcripts in GenBank. The primary transcript originally described, contained 11 exons with protein coding beginning on exon 2 and ending in exon 11 (transcript variant 2), resulting in a 398 amino acid protein with two strongly predicted transmembrane domains (TMDs), coded in exons 2 and 7 (isoform 2).
However, a longer transcript (variant 1) is generated with an alternative first exon containing a translational start site that results in an additional 64 amino acids at the N-terminal extension, 462 amino acids in total (isoform 1).
A third coding transcript (variant 3) splices out exon 7 and produces a shortened and altered carboxy terminus in exon 10, generating a protein of 287 amino acids (isoform 3).   Celias encephalopathy is associated with a mutation in BSCL2' that leads to increased alternative splicing of the pre-mRNA to an mRNA that lacks the seventh exon, corresponding to the second transmembrane domain of the protein product.