does not need. In Fanconi’s syndrome, the renal
tubule excretes into the URINEnumerous vital sub-
stances it should retain in the blood. Among these
substances are GLUCOSE, uric acid, calcium, magne-
sium, potassium, phosphate, and amino acids. The
renal tubule also excretes excessive water into the
urine.
Numerous GENETIC DISORDERS cause Fanconi’s
syndrome. Among the most common are meta-
bolic conditions that affect the body’s ability to use
or store substances such as cystine, glycogen, fruc-
tose, and tyrosine. HEAVY-METAL POISONING, such as
from lead or mercury, and DRUGtoxicity account
for most acquired Fanconi’s syndrome. Conditions
such as AMYLOIDOSIS, in which protein deposits
accumulate in organs such as the kidneys, also can
damage the renal tubules to cause Fanconi’s syn-
drome. The syndrome occasionally develops in
people who undergo KIDNEY TRANSPLANTATION.
Equally numerous symptoms can suggest Fan-
coni’s syndrome and may appear initially to be
unrelated. In children the most common symp-
toms are stunted growth, BONEdeformities similar
to those which occur in RICKETS, and MUSCLEweak-
ness. In adults, the most common symptoms are
spontaneous FRACTURE, electrolyte imbalance, and
serum acidosis (increased acidity of the blood).
General symptoms sometimes present in children
or adults include excessive thirst and URINATION,
CONSTIPATION, and DEHYDRATION. Blood and urine
tests identify the depletions and excesses of the
substances the renal tubules are failing to reab-
sorb.
Treatment targets the underlying cause when
doctors can identify it and the resulting conditions
when the underlying cause remains unknown
(idiopathic Fanconi’s syndrome). Doctors can treat
many genetic disorders of METABOLISMfrom early
childhood, forestalling or preventing complica-
tions such as Fanconi’s syndrome. With appropri-
ate treatment kidney function can return to
normal. Untreated Fanconi’s syndrome can
progress to END-STAGE RENAL DISEASE(ESRD), requir-
ing long-term RENAL DIALYSISor kidney transplanta-
tion.
See also CYSTINURIA; ENVIRONMENTAL HAZARD EXPO-
SURE; MINERALS AND HEALTH; OSTEOPOROSIS; WILSON’S
DISEASE.190 The Urinary System