Summary about Disease
Fructose-1,6-bisphosphatase deficiency (FBPase deficiency) is a rare genetic metabolic disorder that affects the body's ability to produce glucose from non-carbohydrate sources (gluconeogenesis). This process is crucial during periods of fasting, prolonged exercise, or illness. When FBPase is deficient, the body cannot effectively raise blood sugar levels, leading to hypoglycemia (low blood sugar). The condition typically presents in infancy or early childhood, but milder forms may appear later in life.
Symptoms
Symptoms can vary in severity and frequency. Common symptoms include:
Hypoglycemia (low blood sugar): Leading to lethargy, irritability, sweating, rapid heart rate, and potentially seizures or coma.
Hyperventilation (rapid breathing): Due to metabolic acidosis (build-up of acid in the body).
Lactic acidosis: High levels of lactic acid in the blood.
Ketosis: Production of ketones as the body tries to use fat for energy.
Hepatomegaly (enlarged liver): Due to fat accumulation.
Failure to thrive: In infants.
Developmental delays (in some cases): Especially if episodes of hypoglycemia are frequent or severe.
Muscle weakness.
Feeding difficulties.
Causes
FBPase deficiency is caused by mutations in the FBP1 gene. This gene provides instructions for making the fructose-1,6-bisphosphatase enzyme. The deficiency is inherited in an autosomal recessive pattern, meaning an individual must inherit two copies of the mutated gene (one from each parent) to develop the disorder.
Medicine Used
There is no specific medication to cure FBPase deficiency. Treatment focuses on preventing and managing episodes of hypoglycemia and metabolic acidosis. This includes:
Glucose/Dextrose: Intravenous glucose administration during acute hypoglycemic episodes.
Dietary Management: Frequent feedings, especially in infants, with a diet rich in carbohydrates and limited in fructose, sucrose, and sorbitol. Avoidance of prolonged fasting.
Cornstarch: Uncooked cornstarch can be used as a slow-release glucose source, particularly at night, to prevent nocturnal hypoglycemia.
Sodium Bicarbonate or other buffer: To correct metabolic acidosis in severe cases.
Is Communicable
No, Fructose-1,6-bisphosphatase deficiency is not communicable. It is a genetic disorder, not an infectious disease.
Precautions
Dietary Management: Strict adherence to a prescribed diet is crucial.
Frequent Monitoring: Regular blood glucose monitoring is essential, especially during periods of illness or stress.
Avoidance of Fasting: Prolonged periods without food should be avoided.
Emergency Plan: Families should have a written emergency plan outlining how to respond to hypoglycemic episodes, including when to administer glucose and when to seek medical attention.
Medical Alert: Individuals with FBPase deficiency should wear a medical alert bracelet or necklace.
Educate Caregivers: Teachers, daycare providers, and other caregivers should be informed about the condition and trained on how to manage hypoglycemic episodes.
Sick Day Management: A plan to manage illness is important, often including more frequent monitoring and carbohydrate intake.
How long does an outbreak last?
FBPase deficiency is not an outbreak-related illness. Episodes of hypoglycemia and metabolic acidosis can occur sporadically, triggered by factors such as illness, fasting, or stress. The duration of these episodes varies depending on the severity and how quickly they are treated. Prompt treatment usually resolves an acute episode within hours.
How is it diagnosed?
Diagnosis typically involves:
Clinical Evaluation: Assessing symptoms and medical history.
Blood Tests: Measuring blood glucose, lactate, ketones, and liver function. Low blood glucose, elevated lactate and ketones are suggestive.
Urine Tests: To detect ketones.
Enzyme Assay: Measuring the activity of FBPase in a liver biopsy. (Less common now due to genetic testing).
Genetic Testing: Sequencing the FBP1 gene to identify mutations. This is the most common method for confirming the diagnosis.
Metabolic Studies: Specialized testing to evaluate metabolic function.
Timeline of Symptoms
Infancy/Early Childhood: Most individuals are diagnosed during infancy or early childhood, often presenting with episodes of hypoglycemia and metabolic acidosis triggered by illness or fasting.
First Few Months: Symptoms may appear in the first few months of life, especially if the infant is not feeding well or experiences frequent infections.
Later Onset: In some cases, symptoms may be milder and not apparent until later in childhood or even adulthood, often triggered by specific stressors like intense exercise or prolonged fasting.
Lifelong: The condition is lifelong, but symptoms can be managed effectively with proper diet and preventative measures.
Important Considerations
Early Diagnosis: Early diagnosis and management are crucial to prevent complications such as developmental delays, brain damage, and even death.
Individual Variability: The severity of FBPase deficiency varies among individuals, even within the same family.
Genetic Counseling: Genetic counseling is recommended for families with a history of FBPase deficiency to assess the risk of recurrence in future pregnancies.
Long-Term Management: FBPase deficiency requires lifelong management and monitoring.
Awareness: Increased awareness among healthcare professionals is essential for prompt diagnosis and treatment.
Research: Ongoing research aims to improve understanding of the condition and develop new treatment strategies.