Fructose biphosphatase deficiencies, also known as fructose-1,6-bisphosphatase deficiencies, are rare genetic disorders that affect the metabolism of fructose in the body. Fructose biphosphatase is an enzyme that plays a key role in the breakdown of fructose, a simple sugar found in many fruits and sweeteners.
In individuals with fructose biphosphatase deficiencies, there is a lack or malfunctioning of this enzyme, leading to an inability to properly process fructose. This results in a buildup of fructose-1,6-bisphosphate, a molecule in the fructose metabolism pathway.
There are two types of fructose biphosphatase deficiencies: type I and type III. Type I, also known as fructose-1,6-bisphosphatase deficiency, is a severe form of the disorder characterized by low blood sugar levels (hypoglycemia), metabolic acidosis, and an inability to tolerate fructose or other sugar-containing foods. It can manifest in early infancy and can potentially be life-threatening.
Type III, also called fructose-1,6-bisphosphatase aldolase deficiency, is a milder form of the disorder that typically becomes apparent in childhood. Symptoms can include fatigue, muscle weakness, and, in some cases, liver abnormalities. Individuals with type III fructose biphosphatase deficiencies can often tolerate small amounts of fructose, but large quantities may still cause symptoms.
Treatment for fructose biphosphatase deficiencies aims to manage symptoms and prevent hypoglycemia. This usually involves strict dietary modifications, such as avoiding foods high in fructose and other sugars. Regular monitoring of blood sugar levels and metabolic health is also important.
