Like the pex19a-1 pex19b-1 double mutant, embryo lethality has been reported for null alleles of most membrane peroxins in Arabidopsis (reviewed in [1]), and PEX19 mutations in the human peroxisome deficiency disease, Zellweger Syndrome, can result in death in infancy [66, 67]. The gene discussed is PEX19; the disease is Zellweger syndrome.