To summarize, it can be said that the severe VLCAD or CPT2 gene mutations (large deletion, nonsense, truncating, but also some point mutations, etc.)lead to complete deficiency of the corresponding enzyme, either due to mRNA decay, to highly unstable proteins, or to fully inactive mutant enzymes. The gene discussed is CPT2; the disease is very long chain acyl-CoA dehydrogenase deficiency.