The observed lower median AA-triggered PGD2 ratio for MCAD patients was perhaps a result of the significantly higher basal PGD2 levels in this group, as in particular PBLs from some MCAD patients with basal PGD2 levels > 1000 pg/ml did not respond with enhanced, but with reduced release of PGD2 upon AA-triggering (Figure 2, Additional file 5). The gene discussed is PTGDS; the disease is medium chain acyl-CoA dehydrogenase deficiency.