| S.N. | Process/Pathway affected | Disease | Major Manifestation |
| 1) | Digestion | Lactose intolerance
Sucrase/Isomaltase deficiency |
Inability to digest dairy products, bloating, pain- abdomen, diarrhea or constipation, etc. |
| 2) | Absorption (SGLT-1or SGLT-2 deficiency) | Glucose/Galactose malabsorption
|
Impaired dietary glucose/galactose absorption (SGLT-1), or
Renal glycosuria (SGLT-2) |
| 3) | Glycolysis | Hexokinase or Pyruvate kinase deficiency (
|
Hemolytic anemia |
| 4) | PDH Complex | PDH complex Deficiency | Failure to thrive, hypotonia and lactic acidosis, etc. |
| 5) | TCA Cycle | Vital to life, no diseases as yet has been reported | Fatal |
| 6) | HMP Pathway | G-6-P dehydrogenase deficiency | Hemolytic anemia or Jaundice |
| 7) | Gluconeogenesis | An imbalance between demand and supply | Hypoglycemia |
| 8) | Uronic acid pathway | Essential pentosuria | Benign and symptomless |
| 9) | Glycogen metabolism pathways | Glycogen storage diseases | Hypoglycemia decreased exercise tolerance and hepatomegaly (symptoms depend on tissue expression of the defect) |
| 10) | Fructose metabolism | Fructosemia & Hereditary fructose intolerance | Inability to digest fructose or fructose-containing nutrients |
| 11) | Galactose metabolism | Galactosuria & Galactosemia | Galactosuria (mostly benign)
Galactosemia- Premature cataract, mental retardation, hepatomegaly and jaundice |
| 12) | Blood glucose homeostasis | Impaired glucose tolerance, Diabetes mellitus | Classical symptoms of Polyuria, polydipsia, polyphagia, and the symptoms of complications. |
