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].