FECH and liver disorder: However, it is worth noting that fech deficiency does not cause liver disease in most patients with EPP1; rather, the disease occurs only in a small minority, with serious liver disease occurring only in a small percentage of cases over their entire life spans, with an incidence of approximately 2–3% [44], even though fech mRNA levels in the zebrafish adult liver are lower than those in the spleen, kidneys, gills, and ovary.