Northern blot analysis revealed Acadm was normally expressed in all tissues analyzed from MCAD+/+ mice with the most robust expression occurring in brown fat, kidney, heart, skeletal muscle, and liver with minimal expression in the brain, white fat, and testes (Figure 2). Interestingly, although RT-PCR amplified an incorrectly spliced Acadm transcript, no Acadm transcripts were detected by northern blot analysis from MCAD−/− mice. These results strongly suggest that the mutant RNA is unstable and degraded rapidly or, alternatively, undergoes nonsense mediated RNA decay.