In people with the genetic defect for AHP, one of the
enzymes in the pathway that creates heme is deficient.
Certain triggers can impact the pathway and can cause
an increase of ALAS1 (aminolevulinic acid synthase 1).
This increase in ALAS1 results in the
buildup of neurotoxic intermediates –
aminolevulinic acid (ALA) and
porphobilinogen (PBG) – throughout
ALA and PBG are harmful to nerve cells and are factors associated with the attacks and disease manifestations characteristic of AHP.