MMA production by CMAMMA fibroblasts and lentiviral complementation with ACSF3. A. Control fibroblasts and fibroblasts from Subjects 1–4 were incubated in medium containing 5 mM sodium propionate at 37°C for 72 hours and the media was removed for GC/MS analysis of MMA. The CMAMMA patient cells showed increased accumulation of MMA in the media, which were 6, 2.4, 5.3 and 2.4 fold elevated compared to the control cell lines. Error bars are +/− 1 standard deviation (n=3 measurements per cell line). B. Fibroblasts from Subjects 1, 3 and 4 were transduced with lentivirus designed to express ACSF3 or GFP and then incubated in medium containing 5 mM sodium propionate as described. Fibroblasts transduced with ACSF3, but not GFP, exhibit MMA production similar to control fibroblasts treated in a similar fashion. Error bars are +/− 1 standard deviation (n=3 replicates per cell line).