Fanconi syndrome causes the proximal renal tubules of the kidney to not properly reabsorb electrolytes and nutrients back into the body, but instead "spill" them in the urine. Symptoms include excessive drinking, excessive urination, and glucose in the urine. If Fanconi is left untreated, muscle wasting, acidosis, and poor condition will also occur. Age of onset on average between 4 and 8 years of age. Since the disease is typically not discovered until the dog is older, the condition is often passed on to offspring as it was not known that the parent was affected. Fanconi syndrome is progressive, and left untreated can be fatal.