neurodegeneration with the brain iron accumulation ( nbia ) encompasses a genetically heterogeneous group of disorders characterized by the progressive iron accumulation in the basal ganglia . among different subtypes of nbia , the term  pantothenate kinase - associated neurodegeneration ( pkan )  has been coined to describe the subgroup of patients harboring mutations in the pank2 gene whose function is presumed to be related with the regulation of iron metabolism . in addition , the  eye - of - the - tiger sign is recognized as a characteristic brain magnetic resonance imaging ( mri ) finding among patients with the pkan , ( hypo intensity with the central hyper intensity in the globus pallidus on t2 images ) , and predicts a pank2 mutation in at least one allele . deep brain stimulation ( dbs ) of the globus pallidus internus ( gpi ) , has been tried for these patients.[48 ] thereby modulating the abnormal tone in pkan and has been found effective in such cases . a young girl suffering from disabling dystonia secondary to pkan is reported . a 10-year - old girl born of non - consanguineous marriage was apparently well up to 2.5 years of age with the normal development . thereafter , she developed frequent falls while walking without any visual disturbances and had mild slurring of speech . at this time , she had normal hearing and cognition . physical examination revealed unsteady gait with mild dystonia in all extremities along with mild dysarthria with normal sensory and cranial nerve examination . eye of tiger  appearance ( fluid attenuated inversion recovery sequence { flair } ) hyperintensities in bilateral globus pallidi with surrounding hypointensity ) . diagnosis of halloverdan spatz disease ( pkan ) was confirmed as pank2 gene deletion testing was positive . medical management comprising of trihexiphenidyl , baclofen , clonazepam , l - dopa , and botulinum toxin was tried with little therapeutic success in arresting the symptom progression . over the ensuing years , there was gradual worsening in her mobility and ability to do activities of daily living . she developed severe generalized dystonia affecting her limbs , trunk , face , and tongue causing difficulty in walking , dressing , use of hands , difficulty in opening eyes due to severe blepharospasm and problems with chewing , deglutition , vocalization , and maintaining hygiene . she was totally wheel chair bound for mobility by 7 years of age . at the age of 9 years , she had severe dystonic spasms and marked discomfort from dystonia . pre - dbs assessment denoted  burke - fahn - marsden ( bfm ) dystonia rating scale motor score  120/120 and  bfm dystonia rating scale disability score there was a definite improvement in the dystonia post - operatively , which was sustained even at 15 months post - dbs . the bfm dystonia rating scale motor score improved to 42.5/120 while bfm dystonia rating scale disability score improved to 25/29 . this was reflected in her ability to sit in a chair , stand and walk few steps with support , opening eyes and ease in chewing and swallowing food pkan is a rare iron accumulating neurodegenerative movement disorder characterized by typical appearance of the globus pallidi on mri and genetic studies positive for the pank2 gene deletion in a subset of these children . c.215_216insa is the most common pank2 gene mutation observed in indian population mostly belonging to the agarwal community as also seen in our patient . dystonia is the most distressing symptom and the least amenable to medical treatment . in the past however , it has fallen into disrepute on account of the irreversible nature and procedure related adverse effects including cognitive affection . recently , a new concept of electrically stimulating the specific part of the globus pallidus by surgically inserted electrodes , has gathered much interest in managing dystonia resistant to the pharmacological therapy.[1214 ] while the beneficial effects and efficacy of this therapy , which was first introduced in 1977 , have been established in primary dystonias , it still requires validation in the secondary dystonias where the effect is variable . stimulation of postero - ventrolateral part of gpi reversibly inhibits the pathologically activated neuronal activity in this area and facilitates gamma - aminobutyric acid ( gaba ) activity thereby normalizing the increased motor tone . precise target localization is essential for ensuring optimal benefits of the surgery and protecting adjacent vital areas . it can be achieved using a combination of mri , ventriculography and perioperative microelectrode recording data . following the target localization , the therapeutic setting involves establishing optimal frequency , amplitude and pulse width , which is titrated to the desired outcome thereby balancing the benefits and untoward effects of the procedure . the extent of disability preoperatively is compared with post - operative assessment using bfm dystonia rating motor and disability scores . the beneficial effect is protracted over months but is sustained for up to 8 years post - operatively . although speech and swallowing improve marginally , axial dystonia significantly improves with reduced pain and improved quality of life as also seen in our patient . complications include device related adverse effects such as electrode displacement , fracture and rebound dystonia resulting from depletion of the stimulatory source or stimulation related extrapyramidal side - effects . cognition and mood remains unaffected unlike with ablative surgeries carried out in the past . in a multi - centric study from germany , 23 confirmed cases of pkan who failed medical management for dystonia were subjected to dbs with amelioration of dystonia . the mean age at the onset of symptoms was 7.8  4.8 years , mean age at diagnosis was 12.7  8.0 years while the mean age at surgery was 18.0  8.8 years with the youngest patient being 6 years old at the time of surgery . post - operative improvement in the dystonia was 28.5% at 2 - 6 months , 25.7% at 9 - 15 months with 15.8% improvement in the disability . french group reported sustained benefit of the dbs in improving incapacitating dystonia in 7 children suffering from pkan followed over a period of twenty months . near normal functional improvement in an independent walking and writing was noted in 5 patients , with substantial improvement in speech and pain in the majority without any untoward therapy related adverse effects . the degree of improvement in dystonia is directly proportional to the severity of dystonia pre - operatively . prolonged disease duration and fixed skeletal deformities are associated with unfavorable outcome post - operatively .
pantothenate kinase - associated neurodegeneration ( pkan ) is an uncommon extrapyramidal movement disorder characterized by the progressive incapacitating dystonia . 
 medical management is often incapable of reversing the dystonic symptoms . in recent years 
 , stereotactic procedure like deep brain stimulation has been found effective in resolving the disabling dystonia and improving the quality of life . 
 there are few cases in the world literature highlighting the usefulness of this technique . 
 we report a case of 10-year - old girl who underwent bilateral globus pallidus internus stimulation for pkan .