Third, only one of the negatively affected peroxisomal proteins, PEX13, had previously been observed for TRAP-deficient fibroblasts from patients who suffer from congenital disorders of glycosylation (CDG) and are either SSR3- (coding for TRAPγ) or SSR4 (TRAPδ)-deficient [46]. Here, SSR4 is linked to congenital disorder of glycosylation.