In agreement with prior reports [51], PBD-ZSD patient skin fibroblasts with biallelic null mutations in PEX1 (PBD_fs1 and PBD_fs2) grown in fibroblast or iPSC growth media showed over a threefold average reduction in relative PE plasmalogen levels compared to controls (Additional file 3, Student t-test not performed due to limited sample sizes). This evidence concerns the gene PEX1 and peroxisome biogenesis disorder.