Fatty Acid and Protein Metabolism (1D) Practice Test

A patient with exercise intolerance is found to carry a homozygous missense variant in the gene encoding medium-chain acyl-CoA dehydrogenase (MCAD), a mitochondrial enzyme used during beta-oxidation of medium-chain fatty acids. During a supervised 18-hour fast, plasma measurements were obtained.

Based on the experimental setup, what is the most likely effect of the mutation on metabolism?

A patient has a mutation that reduces activity of medium-chain acyl-CoA dehydrogenase (MCAD). During an overnight fast, plasma acylcarnitine profiling shows elevated medium-chain acylcarnitines, while urinary ketones are low despite hypoglycemia.

Based on the experimental setup, what is the most likely effect of the mutation on metabolism?