Medium chain acyl dehydrogenase deficiency (MCADD) occurs when an enzyme called medium chain acyl-CoA dehydrogenase (MCAD) is either missing or does not work properly because of a fault in the gene that provides instructions for making this enzyme. This means that your body cannot break down stored fat to release energy.
Fats are normally broken down into fatty acids, which are then broken down into shorter and shorter lengths, with each step producing energy. If you have MCADD, there is a build-up of medium-length chains due to the lack of the MCAD enzyme.
If you need to break down fats quickly (for example, when you have not eaten for a while or when you have an infection), this build-up of medium-chain fats can become toxic, leading to serious symptoms and even death.
If you have MCADD, you must rely on glucose (a type of sugar in the blood) to produce energy. If you are not eating properly or are ill, your glucose may be all used up and your blood sugar levels may drop to a dangerously low level, with a build-up of toxins in your blood.
