A very long chain fatty acid (VLCFA) is a fatty acid with 22 or more carbons. Their biosynthesis occurs in the endoplasmic reticulum. VLCFA's can represent up to a few percent of the total fatty acid content of a cell.
Unlike most fatty acids, VLCFAs are too long to be metabolized in the mitochondria, and must be metabolized in peroxisomes.
Certain peroxisomal disorders, such as adrenoleukodystrophy and Zellweger syndrome, can be associated with an accumulation of VLCFAs.
References
Very long chain fatty acid Wikipedia(Text) CC BY-SA