Fanconi syndrome Causes And Symptoms
Fanconi syndrome is a renal disease in which amino acids, glucose, phosphate, uric acid and bicarbonate are lost in urine instead of being reabsorbed. Multiple electrolyte imbalances occur (hypokalemia, metabolic acidosis, hypercalciuria, albuminuria), which in childhood lead to growth retardation and later in life to osteoporosis and osteomalacia. Fanconi syndrome is of several types: hereditary, acquired or produced by exogenous substances.
Hereditary Fanconi syndrome occurs due to congenital metabolic abnormalities caused by different genetic mutations. Nephrotic syndrome, immune reactions, various heavy metals and medicines lie behind the other two types of Fnaconi syndrome: acquired Fanconi syndrome respectively Fanconi syndrome induced by exogenous substance.
Hereditary Fanconi syndrome
Different genetic diseases are associated with hereditary Fanconi syndrome: Dent’s disease, Lowe syndrome, cystinosis, galactosemia, von Gierke disease, Wilson’s disease, tyrosinemia and others. These are rare genetic diseases, usually autosomal recessive. Two of them, Lowe syndrome and Dent disease, are X-linked disease which means they are manifested only in boys ( girls are carriers of the defective gene but they do not develop the disease).
Acquired Fanconi syndrome
In terms of acquired Fanconi syndrome, there are several immune and hematologic diseases that may cause proteinuria because Fanconi syndrome is associated with nephrotic syndrome. Multiple myeloma, Sjogren’s syndrome, various nephritis (interstitial nephritis), amyloidosis can cause Fanconi syndrome at a time.
Fanconi syndrome induced by exogenous substances
There are a variety of medications and various exogenous substances that are responsible for Fanconi syndrome. Aminoglycosides, salicylates, valproic acid, tetracycline expired alter proximal renal tubule function and causes abnormal transport of various compounds. Various drugs that are used in the treatment against HIV or chemotherapy (tenofovir, adefovir, cisplatin) may affect kidney function and may lead to Fanconi syndrome. Also, heavy metals such as mercury, cadmium, lead, platinum, are very toxic to the kidneys even in very small doses.
Signs and symptoms
Dehydration and electrolyte imbalances are the main manifestations of Fanconi syndrome. Polyuria, polydipsia and dehydration occur due to large quantities of solutes and water that are lost in the urine. Hypokalemia, which is due to increased secretion of potassium, leads to muscle weakness, fatigue, cardiac arrhythmias to sudden death. In addition to hypokalemia, hypophosphatemia and acidosis may also occur. Proteinuria is not usually significant, except for cases in which Fanconi syndrome is associated with nephrotic syndrome.
The main feature of children with Fanconi syndrome is growth retardation, which is the consequence of all these imbalances. Loss of calcium and phosphate in the urine leads to alterations in mineral and vitamin D metabolism and this results in rickets in children and osteoporosis in adults.