 Additionally, unlike the other condition the arises out of a mutation of the ALAS2 gene, there is no anaemia.XDEPP is characterized by a buildup of protoporphyrin IX caused by in increased level of function in the ALAS2 enzyme.Because there is a buildup of protoporphyrin IX with no malfunction of the FECH enzyme, all the available Fe2+ is used in the production of heme, causing the FECH enzyme to use Zn2+ in its place, causing a buildup of zinc-protoporphyrin IX.