(See also Introduction to Disorders of Kidney Tubules Introduction to Disorders of Kidney Tubules The kidneys filter and cleanse the blood. They also maintain the body’s balance of water, electrolytes (such as sodium, potassium, bicarbonate, and chloride), and nutrients in the blood. The... read more .)
Fanconi syndrome is unrelated to—and should not be confused with—Fanconi anemia.
Fanconi syndrome may be hereditary or may be caused by
Exposure to certain drugs (including some chemotherapy and antiretroviral drugs)
Exposure to heavy metals or other chemicals
Fanconi syndrome usually occurs with another hereditary disorder, such as cystinosis. Cystinosis is an inherited disorder of amino acid metabolism Overview of Amino Acid Metabolism Disorders Amino acid metabolism disorders are hereditary metabolic disorders. Hereditary disorders occur when parents pass the defective genes that cause these disorders on to their children. In most... read more characterized by abnormal deposits of the amino acid cystine throughout the body and abnormal concentrations of cystine in the urine. Abnormal cystine deposits cause eye disorders, an enlarged liver, and an underactive thyroid gland.
Symptoms of Fanconi Syndrome
In hereditary Fanconi syndrome, symptoms of excessive drinking and excessive urination usually begin during infancy.
A child with Fanconi syndrome and cystinosis may have failure to thrive Failure to Thrive Failure to thrive is a delay in weight gain and physical growth that can lead to delays in development and maturation. Medical disorders and a lack of proper nutrition are causes of failure... read more , slowed growth, and chronic kidney disease Chronic Kidney Disease Chronic kidney disease is a slowly progressive (months to years) decline in the kidneys’ ability to filter metabolic waste products from the blood. Major causes are diabetes and high blood pressure... read more . Kidney failure may require a kidney transplant Kidney Transplantation Kidney transplantation is the removal of a healthy kidney from a living or recently deceased person and then its transfer into a person with end-stage kidney failure. (See also Overview of Transplantation... read more 
during childhood.
In adults, symptoms may not develop until the disorder has been present for some time. The most common symptoms in adults include weakness and bone pain.
Most often, some damage to bones or kidney tissue has occurred before the diagnosis is made.
Diagnosis of Fanconi Syndrome
Blood and urine tests
The symptoms and a test that shows abnormalities in the blood (such as a high level of acid) or urine (such as a high level of glucose) may lead a doctor to suspect Fanconi syndrome. The diagnosis is confirmed when high levels of glucose (despite a normal blood glucose), phosphates, and amino acids are detected in the urine.
Treatment of Fanconi Syndrome
Drinking sodium bicarbonate
Fanconi syndrome cannot be cured, but it can be controlled with proper treatment. Effective treatment can keep the damage to bones and kidney tissue from getting worse and in some cases correct it. The high acid level of the blood (acidosis) may be neutralized by drinking sodium bicarbonate. People with low potassium levels in the blood may need to take potassium supplements by mouth.
Bone disease requires treatment with phosphates and vitamin D supplements given by mouth.
Kidney transplantation Kidney Transplantation Kidney transplantation is the removal of a healthy kidney from a living or recently deceased person and then its transfer into a person with end-stage kidney failure. (See also Overview of Transplantation... read more may be lifesaving if a child with the disorder develops kidney failure, but if cystinosis is the underlying disease, progressive damage may continue in other organs and eventually result in death.
More Information
The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): Insight into ongoing research, consumer health information in English and Spanish, a blog, and community health and outreach programs.
