Summary about Disease
Fanconi-Bickel syndrome (FBS) is a rare, inherited disorder affecting how the body processes certain sugars, particularly glucose and galactose. It primarily impacts the kidneys, liver, and intestines. The syndrome leads to glycogen accumulation in these organs, causing a variety of health problems.
Symptoms
Glycogen storage: Enlarged liver (hepatomegaly) and kidneys (nephromegaly) due to glycogen accumulation.
Glucose-galactose malabsorption: Impaired absorption of glucose and galactose in the intestines, leading to diarrhea, dehydration, and failure to thrive in infancy.
Renal tubular dysfunction: Impaired kidney function, causing glucose in the urine (glucosuria), amino acids in the urine (aminoaciduria), phosphate loss, and increased excretion of electrolytes.
Rickets: Bone abnormalities due to phosphate loss and vitamin D deficiency.
Short stature: Growth retardation is common.
Truncal obesity: Increased fat around the abdomen.
Abdominal distension: Caused by the enlarged liver and kidneys.
Vomiting: Frequent vomiting in early childhood.
Causes
FBS is caused by mutations in the SLC2A2 gene. This gene provides instructions for making a protein called GLUT2, which is a glucose transporter. GLUT2 is responsible for transporting glucose and galactose across cell membranes in the liver, kidneys, intestines, and pancreas. Mutations in *SLC2A2* impair the function of GLUT2, leading to the accumulation of glucose and glycogen in these organs and the malabsorption of glucose and galactose in the intestines. The condition is inherited in an autosomal recessive pattern, meaning that both parents must carry a copy of the mutated gene for their child to be affected.
Medicine Used
There is no specific cure for FBS. Treatment focuses on managing the symptoms and preventing complications. Medical management may include:
Dietary modifications: A diet restricted in galactose and glucose but enriched in fructose can help to reduce the buildup of glycogen and the malabsorption issues.
Vitamin D and phosphate supplementation: To treat and prevent rickets and maintain bone health.
Electrolyte management: Monitoring and correcting electrolyte imbalances caused by renal tubular dysfunction.
Growth hormone therapy: May be considered to improve growth in some cases.
Management of kidney function: Medications to address specific kidney problems as needed.
Supportive care: Managing dehydration and diarrhea with intravenous fluids and other supportive measures.
Is Communicable
No, Fanconi-Bickel syndrome is not communicable. It is a genetic disorder caused by a mutation in the SLC2A2 gene and is not caused by an infectious agent.
Precautions
There are no general precautions to prevent FBS, as it is a genetic condition. For individuals diagnosed with FBS, precautions are focused on managing the condition and preventing complications:
Strict adherence to dietary recommendations: Carefully following the prescribed diet to minimize glucose and galactose intake is crucial.
Regular monitoring of blood and urine: To assess kidney function, electrolyte balance, and glucose/galactose levels.
Bone health monitoring: Regular monitoring of bone density and vitamin D levels.
Preventative measures against infections: Individuals with FBS may be more susceptible to infections due to impaired immune function.
Genetic counseling: For families with a history of FBS, genetic counseling can help assess the risk of having a child with the condition.
How long does an outbreak last?
FBS is not an infection or outbreak, but a chronic genetic condition. Symptoms can be present from infancy and persist throughout life. The severity of symptoms can vary over time, but the underlying condition is always present.
How is it diagnosed?
Diagnosis of FBS typically involves:
Clinical evaluation: Assessing the symptoms, such as enlarged liver and kidneys, short stature, truncal obesity, and growth failure.
Laboratory tests:
Urine analysis: To detect glucosuria, aminoaciduria, and electrolyte abnormalities.
Blood tests: To measure blood glucose, electrolytes, liver enzymes, phosphate, and vitamin D levels.
Genetic testing: To identify mutations in the SLC2A2 gene.
Liver biopsy: May be performed to confirm glycogen storage in the liver.
Kidney biopsy: May be performed to evaluate renal tubular dysfunction.
Imaging studies: Ultrasound or CT scans may be used to assess the size of the liver and kidneys.
Timeline of Symptoms
Infancy:
Poor feeding
Failure to thrive
Vomiting
Diarrhea
Dehydration
Enlarged liver and kidneys
Childhood:
Short stature
Rickets
Abdominal distension
Truncal obesity
Glucose in urine
Electrolyte imbalances
Adulthood:
Continued short stature
Hepatic adenomas (benign liver tumors) may develop
Chronic kidney disease may develop
Osteopenia/osteoporosis
Important Considerations
Early diagnosis and treatment: Early diagnosis and management are critical to minimize long-term complications and improve the quality of life for individuals with FBS.
Multidisciplinary care: Management of FBS requires a team of specialists, including a pediatrician, endocrinologist, nephrologist, gastroenterologist, and dietitian.
Nutritional support: A specialized diet is essential for managing the metabolic abnormalities associated with FBS.
Monitoring for complications: Regular monitoring for liver tumors, kidney disease, and bone abnormalities is important.
Genetic counseling: Genetic counseling is recommended for families with a history of FBS to understand the risk of recurrence and available options for genetic testing.
Support groups: Connecting with other families affected by FBS can provide valuable emotional support and resources.