Fructose bisphosphatase deficiency

Fructose bisphosphatase deficiency is a rare genetic disorder that affects the body's ability to metabolize fructose, a type of sugar. This disorder is inherited in an autosomal recessive manner, meaning that an individual must inherit two copies of the defective gene, one from each parent, in order to develop the condition.

Symptoms

The symptoms of fructose bisphosphatase deficiency typically become apparent in infancy, when fructose is introduced into the diet. These may include hypoglycemia, lactic acidosis, ketosis, and hepatomegaly. In severe cases, the disorder can lead to seizures, coma, and even death.

Causes

Fructose bisphosphatase deficiency is caused by mutations in the FBP1 gene, which provides instructions for making an enzyme called fructose-1,6-bisphosphatase. This enzyme is involved in gluconeogenesis, the process that creates glucose from other substances when dietary glucose is not available. Mutations in the FBP1 gene reduce or eliminate the activity of this enzyme, disrupting gluconeogenesis and leading to the symptoms of the disorder.

Diagnosis

Diagnosis of fructose bisphosphatase deficiency is typically made through biochemical testing, which can detect the presence of certain substances in the blood and urine that are indicative of the disorder. Genetic testing can also be used to identify mutations in the FBP1 gene.

Treatment

There is currently no cure for fructose bisphosphatase deficiency. Treatment is focused on managing the symptoms and preventing metabolic crises. This typically involves a diet that is low in fructose and other sugars that can be converted into fructose. In some cases, medications may be used to manage symptoms such as hypoglycemia.

See also

• Inborn errors of metabolism
• Fructose intolerance
• Glycogen storage disease

NIH genetic and rare disease info

• NIH info on Fructose bisphosphatase deficiency

Fructose bisphosphatase deficiency is a rare disease.