DISCUSSION:
Fahr’s syndrome is usually a bilateral and symmetrical intra-cranial
calcification with a predilection for basal ganglia and dentate nucleus.
Moreover, primary hyperparathyroidism has been closely described in
relation with the bilateral calcific nature of Fahr’s syndrome[2, 5]. However other causes such as lupus,
tuberous sclerosis, Alzheimer’s, muscular dystrophy and mitochondrial
diseases have also been described to be the underlying condition
predisposing Fahr’s syndrome [5, 6]. The exact
prevalence of Fahr’s syndrome is unknown, however it has been
incidentally detected in around 0.3-1.2% of NCCT head examinations[5]. Moreover, the pathophysiology behind Fahr’s
syndrome is poorly understood however anatomical and morphological
changes were seen in small vessels, perivascular regions, neuroglia and
neurons [7]. It should be understood that Fahr’s
disease exhibit clinical heterogeneity, therefore the diagnosis should
be made on the basis of neurological evidence with no alternative
explanation for symmetrical bilateral basal ganglia calcification[7].
The common clinical features include headaches, seizures, and movement
disorders. Gait disturbances, dystonia, paresis, speech alterations,
dementia, tremors, chorea are other specific features seen in Fahr’s
syndrome [2, 5]. This combination of
neuropsychiatric features along with striopallidodentate calcinosis is
known as Fahr’s syndrome [5]. Similarly, the
available epidemiological data suggest higher prevalence of disease in
men with clinical features occurring around the 5thdecade of life. Severe forms of the disease leads to severe
neuropsychiatric manifestations accounting to the degrading quality of
life [7]. Batla et al. in their review article
pointed psychiatric features, movement disorders and cognitive
impairment to be the major manifestations of Fahr’s syndrome[8]. Moreover, Batla et al. have also found that
the evidence of basal ganglia calcification in NCCT head could be as
high as 20%, which shall thus be differentiated with the primary
condition of Fahr’s syndrome [2, 4, 5, 8].
Laboratory examinations should also aim for blood calcium, iPTH, and
other routine blood tests which helps in differentiation of idiopathic
Fahr’s disease with Fahr’s syndrome [5]. Though CT
scans have been found to be of great importance, the role of MRI over CT
has not been well demonstrated [5]. Though, MRI
provides a better anatomical detail than CT scan, it is less specific in
detecting calcifications. Kozic et al reported 3 individuals with
calcifications in the brain which was falsely interpreted in MRI[10]. Similarly, a molecular genetic pattern
testing also helps in the diagnosis of primary and secondary Fahr’s
disease/syndrome; the multigene panel including PDGFB, PDGFRB,
SLC20A2, XPR1 and various other genes of interest[1, 8, 10, 13].