Without effective gluconeogenesis (GNG), hypoglycaemia will set in after about 12 hours of fasting. This is the time when liver glycogen stores have been exhausted, and the body has to rely on GNG. When given a dose of glucagon (which would normally increase blood glucose) nothing will happen, as stores are depleted and GNG doesn't work. (In fact, the patient would already have high glucagon levels.) There is no problem with the metabolism of glucose or galactose, but<unk>  and glycerol cannot be used by the liver to maintain blood glucose levels. If<unk>  or glycerol are given, there will be a buildup of phosphorylated three-carbon sugars. This leads to phosphate depletion within the cells, and also in the blood. Without phosphate, ATP cannot be made, and many cell processes cannot occur. High levels of glucagon will tend to release fatty acids from adipose tissue, and this will combine with glycerol that cannot be used in the liver, to make triacylglycerides causing a fatty liver. As three carbon molecules cannot be used to make glucose, they will instead be made into pyruvate and lactate. These acids cause a drop in the pH of the blood (a metabolic acidosis). Acetyl CoA (acetyl co-enzyme A) will also build up, leading to the creation of ketone bodies.
Fructose bisphosphatase deficiency
Malonyl-CoA decarboxylase deficiency
Triosephosphate isomerase deficiency
Pyruvate kinase deficiency
Glutaminase deficiency
Enolase deficiency
Ribose-5-phosphate isomerase deficiency
Aldolase A deficiency