|Deficient enzyme||Glycogen synthase deficiency|
ALTERNATIVE ENERGY SOURCES
When glucose levels run low, your body needs to produce energy in other ways. One way to do this involves your body using its fat stores to produce ketones. The body can also start to use protein to produce energy.
WHAT ARE KETONES?
Ketones are an alternative source of energy. In healthy individuals, ketone levels are typically very low. Extended fasting can lead to higher levels of ketones. Ketones are produced from the body’s fat stores. The brain needs a lot of energy to work properly but it cannot use fat to produce energy – it prefers glucose. However, the brain can get energy from ketones. If you have GSD type 0, turning fat into ketones helps your brain get energy when glucose levels are low. Ketones also help keep your muscles supplied with energy when your glucose levels are low. Although ketones can be a very useful source of energy, it is important that your ketone levels do not go too high. High ketone levels indicate that GSD control could be better.
Good dietary management aims to reduce the risk of your blood glucose levels going too low. This means that your body will not need to make ketones or break down your muscles to produce energy.
As mentioned, if you have GSD type 0, you may experience both high and low levels of blood glucose. High levels of blood glucose don’t tend to be seen in other forms of GSD.
Unlike other liver GSDs, when untreated, you will NOT get a build-up of glycogen because you cannot make glycogen. Hepatomegaly or an enlarged liver will therefore not be seen.