Striopallidodentate calcinosis (
Fahr's disease) is characterized clinically by
seizures, rigidity, and
dementia and pathologically by
mineral deposition in the basal ganglia, dentate nucleus, and cerebral cortex. Disorders of
iron and
calcium-phosphate metabolism are thought to play a role in its pathogenesis. We present the case of a patient with familial
striopallidodentate calcinosis who had
porphyria cutanea tarda,
refractory anemia, and
pseudohypoparathyroidism type 2. The serum level of
ferritin was markedly increased, serum
iron and
iron-binding capacity were below normal, and at autopsy she had deposition of
iron in liver, spleen, bone marrow, and brain. She showed intermittent mild
hypocalcemia, increased serum values of
parathyroid hormone, elevated renal tubular reabsorption of
phosphate, and low serum levels of
1,25-dihydroxyvitamin D, suggesting blunted renal responsiveness to endogenous
parathyroid hormone.
Pseudohypoparathyroidism type 2 was confirmed by infusion of synthetic
parathyroid hormone, which gave a normal urinary cyclic
adenosine monophosphate response, but a blunted phosphaturic response. After
splenectomy for
hypersplenism and weekly phlebotomies, she showed progressive improvement in function, mental status, weight, and seizure control. The hypothesis advanced is that the underlying pathophysiology of the separate diseases contributed to the formation of the brain stones through mechanisms of defective
iron transport and
free radical production.