NBIAS (Neurodegeneration with Brain Iron Accumulation Syndromes) groups together a series of heterogeneous entities, often also superimposable, whose common characteristic is brain iron accumulation. This accumulation can be seen predominantly at the level of the basal ganglia (especially in the globus pallidus, substantia nigra, and adjacent areas) on brain MR images (T2, spin-echo, and gradient echo sequences). One of its most common forms is pantothenate kinase-associated neurodegeneration (PKAN, formerly called Hallervorden-Spatz syndrome): it is typically recognized on MRI by the “tiger eye” sign (a hypointense area with a hyperintense center in globus pallidus).
Its prevalence is estimated at around 1-3:1,000,000 individuals. They present clinically as neurodegenerative diseases with movement disorders, pyramidal, cerebellar, autonomic, and eventually cognitive and psychiatric signs.
Several genes causing NBIAS have been identified, which we have included in the panel we propose, and whose diagnostic performance explains approximately 65% of the cases (Schneider et al., 2016). In order of importance, we highlight PANK2 (35-50%), PLA2G6 (20%), C19orf12 (6-10%) and WDR45 (1-2%) (Gregory and Hayflick, 2014).