Brain CT scan is the preferred method of localizing and assessing the extent of cerebral calcifications.Elevated levels of copper, iron, magnesium and zinc but not calcium have been reported in the CSF but the significance of this finding — if any — is not known.The diagnosis requires the following criteria be met:
the presence of bilateral calcification of the basal ganglia
the presence of progressive neurologic dysfunction
the absence of an alternative metabolic, infectious, toxic or traumatic cause
a family history consistent with autosomal dominant inheritanceThe calcification is usually identified on CT scan but may be visible on plain films of the skull. Differential diagnosis
Basal ganglia calcification may occur as a consequence of several other known genetic conditions and these have to be excluded before a diagnosis can be made. Management
There is currently no cure for PFBC nor a standard course of treatment. The available treatment is directed symptomatic control. If parkinsonian features develop, there is generally poor response to levodopa therapy. Case reports have suggested that haloperidol or lithium carbonate may help with psychotic symptoms. One case report described an improvement with the use of a bisphosphonate. Prognosis
The prognosis for any individual with PFBC is variable and hard to predict. There is no reliable correlation between age, extent of calcium deposits in the brain, and neurological deficit. Since the appearance of calcification is age-dependent, a CT scan could be negative in a gene carrier who is younger than the age of 55.Progressive neurological deterioration generally results in disability and death.
This suggests there may be some genetic heterogeneity in this disease.A mutation in the gene encoding the type III sodium dependent phosphate transporter 2 (SLC20A2) located on chromosome 8 has been reported. Biochemical evidence suggests that phosphate transport may be involved in this disease.Two other genes have been associated with this condition: PDGFB on chromosome 22 and PDGFRB on chromosome 5. These genes are biochemically linked: PDGFRB encodes the platelet-derived growth factor receptor β and PDGFB encodes the ligand of PDGF-Rβ. These genes are active during angiogenesis to recruit pericytes which suggests that alterations in the blood brain barrier may be involved in the pathogenesis of this condition.A fourth gene associated with this condition is XPR1. This gene is the long arm of located on chromosome 1 (1q25.3).Another gene that has been associated with this condition is MYORG. This gene is located on the long arm of chromosome 9 (9p13.3). This gene is associated with an autosomal recessive inheritance pattern in this condition.Another gene junctional adhesion molecule 2 (JAM2) has been associated with an autosomal recessive form of this condition. Other genes that have been associated with this condition are Junctional adhesion molecule C (JAM3) and Occludin (OCLN). Pathology
The most commonly affected region of the brain is the lenticular nucleus and in particular the internal globus pallidus. Calcifications in the caudate, dentate nuclei, putamen and thalami are also common.