Very rare degenerative neurologic syndrome
characterized by microcephaly, mental and growth retardation, seizures and
dystonic movements, and athetosis with evidence of multiple intracranial
calcifications in parts of the gray and dentate nuclei, particularly of
smaller brain vessels.
Cerebral Nonarteriosclerotic Calcification; Idiopathic
Basal Ganglia Calcification; Fahr Intracerebral Calcinosis; Fahr Disease;
Morbus Fahr Ferrocalcinosis; Nonarteriosclerotic Cerebral Calcifications;
Striopallidodentate (SPD) Calcinosis.
Presence of idiopathic intracranial calcifications has been
recognized for many years. The initial report by Fahr was about an adult.
The heterogeneous nature of the disease was later recognized and genetic
conditions occurring in infants were included.
Autosomal recessive and autosomal dominant
transmission have been reported. In some cases, the condition appears to be
sporadic and may result from an unidentified infection during pregnancy
affecting the developing fetus.
Pathogenesis is unclear, but a few hypotheses have
been stated, such as the possible role of abnormal iron transport, fetal
viral infection, and hypoparathyroidism.
Diagnosis of exclusion after ruling out common causes of
microcephaly with intracranial calcifications, such as TORCH (toxoplasmosis,
other agents, rubella, cytomegalovirus, herpes simplex) infection, varicella
virus, and cytomegalovirus infections.
Children affected with the disease are normal at
birth but then show poor psychomotor developmental progress. Seizures
appear early in life and are of variable nature. Affected patients present
with severe microcephaly, hypotonia, spasticity, and growth retardation.
Some children also have thrombocytopenia and hepatosplenomegaly manifesting
shortly after birth but lasting for only a few weeks and then resolving
spontaneously. CT scan of the brain may show cerebral atrophy, dilated
ventricles, calcifications, and a lower density of white matter consistent
with dysmyelination. Hypoparathyroidism may be associated with this
disorder. Clinical course and outcome are highly variable.
If the child needs surgery in the
first few weeks of life, obtain a complete blood count (CBC) to rule out anemia and
thrombocytopenia. Blood calcium should be checked to rule out hypocalcemia
caused by hypoparathyroidism.
Locoregional anesthesia should be
avoided in case of thrombopenia.
Presence of undetermined cause for
hepatomegaly should limit the use of inhalational agent likely to affect the
liver (e.g., halothane). Hepatic enzyme induction may occur in the presence
of anticonvulsant, so the dose of some drugs, such as neuromuscular
relaxants, may require adjustment. It is best to avoid succinylcholine if
the patient has severe spastic paraplegia.
Hempel A, Henze M, Berghoff C, et al: PET findings and neuropsychological
deficits in a case of Fahr's disease. Psychiatry Res
Morgante L, Trimarchi F, Benvenga S: Fahr's disease. Lancet
Reardon W, Hockey A, Silberstein P, et al: Autosomal recessive congenital
intrauterine infection-like syndrome of microcephaly, intracranial
calcification, and CNS disease. Am J Med Genet 52;58, 1994.