Hallervorden-Spatz syndrome

Cognitive and Physical Intervention in Metals’ Dysfunction and Neurodegeneration

Metals—especially iron, copper and manganese—are important elements of brain functions and development. Metal-dysregulation homeostasis is associated with brain-structure damage to the motor, cognitive and emotional systems, and leads to neurodegenerative processes. There is more and more evidence that specialized cognitive and motor exercises can enhance brain function and attenuate neurodegeneration in mechanisms, such as improving neuroplasticity by altering the synaptic structure and function in many brain regions. Psychological and physical methods of rehabilitation are now becoming increasingly important, as pharmacological treatments for movement, cognitive and emotional symptoms are limited. The present study describes physical and cognitive rehabilitation methods of patients associated with metal-induced neurotoxicity such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, Huntington’s disease and Wilson’s disease. In our review, we describe physical (e.g., virtual-reality environments, robotic-assists training) and psychological (cognitive training, cognitive stimulation, neuropsychological rehabilitation and cognitive-behavioral and mindfulness-based therapies) methods, significantly improving the quality of life and independence of patients associated with storage diseases. Storage diseases are a diverse group of hereditary metabolic defects characterized by the abnormal cumulation of storage material in cells. This topic is being addressed due to the fact that rehabilitation plays a vital role in the treatment of neurodegenerative diseases. Unfortunately so far there are no specific guidelines concerning physiotherapy in neurodegenerative disorders, especially in regards to duration of exercise, type of exercise and intensity, as well as frequency of exercise. This is in part due to the variety of symptoms of these diseases and the various levels of disease progression. This further proves the need for more research to be carried out on the role of exercise in neurodegenerative disorder treatment.

PANK2 p.A170fs：a novel pathogenetic mutation, compound with PANK2 p.R440P, causing pantothenate kinase Associated neurodegeneration in a Chinese family

AIM

Pantothenate kinase associated neurodegeneration (PKAN) is a severe autosomal recessive rare disease and characterized by iron accumulation in the basal ganglia. To investigate the pathogenesis of this disease in two sibling patients with PANK in a Chinese family, whole-exome variant detection and functional analysis were performed.

MATERIALS AND METHODS

Clinical and radiographic investigations were performed in the two brother patients. Whole exome sequencing (WES) was used in mutation detection, and the mutations were confirmed by Sanger sequencing. A longevity cohort genetic database was applied as Chinese urban controls. Bioinformatic analysis was performed to predict the pathogenicity.

RESULTS

Compound heterozygous mutations of PANK2 were detected in two sibling brothers with PKAN in a Chinese family: c.510_522del (p.A170fs) and c.1319G > C (p.R440P) in the transcript NM_153638. PANK2: c.510_522del (p.A170fs) was absent in public data and the Chinese urban controls. Bioinformatics analysis showed that the above two variants were pathogenicity.

CONCLUSIONS

We identified a rare compound heterozygous combination of PANK2 mutations found in a Chinese family in which two sibling brothers suffered from PKAN. PANK2 c.510_522del (p.A170fs) was the first reported to be a PKAN pathogenic variant.

Atypical pantothenate kinase-associated neurodegeneration with PANK2 mutations : clinical description and a review of the literature

Panthothenate kinase-associated neurodegeneration (PKAN) is arare neurodegeneration caused by mutations in the pantothenate kinase (PANK2) gene, which is located on chromosome 20p13. These mutations result in iron accumulation in the brain basal ganglia leading to parkinsonism, dysarthria, spasticity, cognitive impairment, and retinopathy. Herein, we report acase of adult-onset PKAN who presented with young-onset action tremor, bradykinesia, dysarthria, and bilateral interossei atrophy.  Neuroimaging demonstrated "eye-of-the-tiger signs". Through analyzing PANK2 gene, PANK2 NM_153638:c.1133A>G (p.Asp378 Gly) and PANK2 NM_153638:c.1502 T > A (p.lle501Asn), were detected. In addition, we reviewed the clinical and genetic features and therapeutic strategies for patients with PKAN.

Deep brain stimulation as treatment for dystonic storm in pantothenate kinase-associated neurodegeneration syndrome: case report of a patient with homozygous C.628 2 T > G mutation of the PANK2 gene

Pantothenate kinase-associated neurodegeneration (PKAN) syndrome is an autosomal-recessive neurodegenerative disease that causes progressive generalized dystonia. Currently, the disorder remains pharmacologically intractable. Herein we report the first case in which deep brain stimulation helped to relieve dystonic storm in a patient with PKAN syndrome who had homozygous c.628 2 T > G mutation of the PANK2 gene. A 10-year-old boy with PKAN disease presented with dystonic storm and was admitted to the emergency department. Examination revealed generalized dystonia and impaired breathing due to involvement of the respiratory muscles. The patient underwent surgery for bilateral globus pallidus internus deep brain stimulation. The patient showed marked response to treatment.

Hepcidin Suppresses Brain Iron Accumulation by Downregulating Iron Transport Proteins in Iron-Overloaded Rats

Iron accumulates progressively in the brain with age, and iron-induced oxidative stress has been considered as one of the initial causes for Alzheimer's disease (AD) and Parkinson's disease (PD). Based on the role of hepcidin in peripheral organs and its expression in the brain, we hypothesized that this peptide has a role to reduce iron in the brain and hence has the potential to prevent or delay brain iron accumulation in iron-associated neurodegenerative disorders. Here, we investigated the effects of hepcidin expression adenovirus (ad-hepcidin) and hepcidin peptide on brain iron contents, iron transport across the brain-blood barrier, iron uptake and release, and also the expression of transferrin receptor-1 (TfR1), divalent metal transporter 1 (DMT1), and ferroportin 1 (Fpn1) in cultured microvascular endothelial cells and neurons. We demonstrated that hepcidin significantly reduced brain iron in iron-overloaded rats and suppressed transport of transferrin-bound iron (Tf-Fe) from the periphery into the brain. Also, the peptide significantly inhibited expression of TfR1, DMT1, and Fpn1 as well as reduced Tf-Fe and non-transferrin-bound iron uptake and iron release in cultured microvascular endothelial cells and neurons, while downregulation of hepcidin with hepcidin siRNA retrovirus generated opposite results. We concluded that, under iron-overload, hepcidin functions to reduce iron in the brain by downregulating iron transport proteins. Upregulation of brain hepcidin by ad-hepcidin emerges as a new pharmacological treatment and prevention for iron-associated neurodegenerative disorders.

Update on neurodegeneration with brain iron accumulation

Neurodegeneration with brain iron accumulation (NBIA) defines a heterogeneous group of progressive neurodegenerative disorders characterized by excessive iron accumulation in the brain, particularly affecting the basal ganglia. In the recent years considerable development in the field of neurodegenerative disorders has been observed. Novel genetic methods such as autozygosity mapping have recently identified several genetic causes of NBIA. Our knowledge about clinical spectrum has broadened and we are now more aware of an overlap between the different NBIA disorders as well as with other diseases. Neuropathologic point of view has also been changed. It has been postulated that pantothenate kinase-associated neurodegeneration (PKAN) is not synucleinopathy. However, exact pathologic mechanism of NBIA remains unknown. The situation implicates a development of new therapies, which still are symptomatic and often unsatisfactory. In the present review, some of the main clinical presentations, investigational findings and therapeutic results of the different NBIA disorders will be presented.

Phenotypes and genotypes of patients with pantothenate kinase-associated neurodegeneration in Asian and Caucasian populations: 2 cases and literature review

Objectives. Pantothenate kinase-associated neurodegeneration (PKAN) is a rare disease caused by pantothenate kinase 2 (PANK2, OMIM 606157) mutations. This study is aimed to investigate clinical presentations, pathologies, and genetics in patients with PKAN. Methods. Two patients with PKAN were reported. We reviewed the literature to include additional 19 patients with PKAN in Eastern Asia. These patients were divided into classic and atypical groups by the age of onset. We compared the data on PKAN patients of Asian and Caucasian populations. Results. We found iron deposits in the globus pallidus in our Patient 1 and a heterozygous truncating mutation (c.1408insT) in Patient 2. Literature review shows that generalized dystonia and bulbar signs are more common in classic PKAN patients, whereas segmental dystonia and tremors are more specific to atypical ones. Asian patients have less complex presentations—lower prevalence of pyramidal signs, mental impairment, and parkinsonism—than Caucasians. D378G in exon 3 is the most frequent mutation (28%) in Asians. Conclusions. Our study demonstrates that the distribution of dystonia is the major distinction between subgroups of PKAN. Caucasian patients have more complex presentations than Asians. Exon 3 and 4 are hot spots for screening PANK2 mutations in Asian patients.

Pantothenate kinase-associated neurodegeneration (PKAN) and PLA2G6-associated neurodegeneration (PLAN): review of two major neurodegeneration with brain iron accumulation (NBIA) phenotypes

Neurodegeneration with brain iron accumulation (NBIA) comprises a heterogeneous group of disorders characterized by the presence of radiologically discernible high brain iron, particularly within the basal ganglia. A number of childhood NBIA syndromes are described, of which two of the major subtypes are pantothenate kinase-associated neurodegeneration (PKAN) and PLA2G6-associated neurodegeneration (PLAN). PKAN and PLAN are autosomal recessive NBIA disorders due to mutations in PANK2 and PLA2G6, respectively. Presentation is usually in childhood, with features of neurological regression and motor dysfunction. In both PKAN and PLAN, a number of classical and atypical phenotypes are reported. In this chapter, we describe the clinical, radiological, and genetic features of these two disorders and also discuss the pathophysiological mechanisms postulated to play a role in disease pathogenesis.

Neurodegeneration with brain iron accumulation - clinical syndromes and neuroimaging

Iron participates in a wide array of cellular functions and is essential for normal neural development and physiology. However, if inappropriately managed, the transition metal is capable of generating neurotoxic reactive oxygen species. A number of hereditary conditions perturb body iron homeostasis and some, collectively referred to as neurodegeneration with brain iron accumulation (NBIA), promote pathological deposition of the metal predominantly or exclusively within the central nervous system (CNS). In this article, we discuss seven NBIA disorders with emphasis on the clinical syndromes and neuroimaging. The latter primarily entails magnetic resonance scanning using iron-sensitive sequences. The conditions considered are Friedreich ataxia (FA), pantothenate kinase 2-associated neurodegeneration (PKAN), PLA2G6-associated neurodegeneration (PLAN), FA2H-associated neurodegeneration (FAHN), Kufor-Rakeb disease (KRD), aceruloplasminemia, and neuroferritinopathy. An approach to differential diagnosis and the status of iron chelation therapy for several of these entities are presented. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease.

Dystonia in neurodegeneration with brain iron accumulation: outcome of bilateral pallidal stimulation

Neurodegeneration with brain iron accumulation encompasses a heterogeneous group of rare neurodegenerative disorders that are characterized by iron accumulation in the brain. Severe generalized dystonia is frequently a prominent symptom and can be very disabling, causing gait impairment, difficulty with speech and swallowing, pain and respiratory distress. Several case reports and one case series have been published concerning therapeutic outcome of pallidal deep brain stimulation in dystonia caused by neurodegeneration with brain iron degeneration, reporting mostly favourable outcomes. However, with case studies, there may be a reporting bias towards favourable outcome. Thus, we undertook this multi-centre retrospective study to gather worldwide experiences with bilateral pallidal deep brain stimulation in patients with neurodegeneration with brain iron accumulation. A total of 16 centres contributed 23 patients with confirmed neurodegeneration with brain iron accumulation and bilateral pallidal deep brain stimulation. Patient details including gender, age at onset, age at operation, genetic status, magnetic resonance imaging status, history and clinical findings were requested. Data on severity of dystonia (Burke Fahn Marsden Dystonia Rating Scale-Motor Scale, Barry Albright Dystonia Scale), disability (Burke Fahn Marsden Dystonia Rating Scale-Disability Scale), quality of life (subjective global rating from 1 to 10 obtained retrospectively from patient and caregiver) as well as data on supportive therapy, concurrent pharmacotherapy, stimulation settings, adverse events and side effects were collected. Data were collected once preoperatively and at 2-6 and 9-15 months postoperatively. The primary outcome measure was change in severity of dystonia. The mean improvement in severity of dystonia was 28.5% at 2-6 months and 25.7% at 9-15 months. At 9-15 months postoperatively, 66.7% of patients showed an improvement of 20% or more in severity of dystonia, and 31.3% showed an improvement of 20% or more in disability. Global quality of life ratings showed a median improvement of 83.3% at 9-15 months. Severity of dystonia preoperatively and disease duration predicted improvement in severity of dystonia at 2-6 months; this failed to reach significance at 9-15 months. The study confirms that dystonia in neurodegeneration with brain iron accumulation improves with bilateral pallidal deep brain stimulation, although this improvement is not as great as the benefit reported in patients with primary generalized dystonias or some other secondary dystonias. The patients with more severe dystonia seem to benefit more. A well-controlled, multi-centre prospective study is necessary to enable evidence-based therapeutic decisions and better predict therapeutic outcomes.

Siblings with the adult-onset slowly progressive type of pantothenate kinase-associated neurodegeneration and a novel mutation, Ile346Ser, in PANK2: clinical features and (99m)Tc-ECD brain perfusion SPECT findings

Pantothenate kinase-associated neurodegeneration (PKAN), formerly known as Hallervorden-Spatz syndrome (HSS), is an autosomal recessive neurodegenerative disorder characterized by iron accumulation in the brain. Mutations in the pantothenate kinase 2 (PANK2) gene are known to be responsible for PKAN. Several studies have revealed correlations between clinical phenotypes and particular PANK2 mutations. The adult-onset slowly progressive type of PKAN with PANK2 mutations is very rare. In this report, we describe siblings with the adult-onset slowly progressive type of PKAN with a novel mutation, Ile346Ser, in PANK2. The siblings had the same mutation in PANK2 and had common clinical signs such as misalignment of teeth, a high arched palate, hollow feet, a slight cognitive decline, and an apparent executive dysfunction, although they showed different patterns of movement disorders. Thus, even if PKAN patients have identical mutations, it is likely that they will present with different types of movement disorders. Brain perfusion single photon emission computed tomography in both patients showed decreased regional cerebral blood flow in the bilateral frontoparietal lobes, the globus pallidus, the striatum, and around the ventriculus quartus. Cardiac uptake of [(123)I] meta-iodobenzylguanidine was normal in both patients. Analysis of genotype-phenotype correlations and the elucidation of mutational effects on pantothenate kinase 2 function, expression, and structure are important for understanding the mechanisms of PKAN.

Psychiatric disorder in two siblings with hallervorden-spatz disease

Hallervorden-Spatz disease (HSD) is a rare autosomal-recessive hereditary disorder characterized by the early onset of progressive movement alterations, including dystonia, rigidity, choreoathetosis, and mental deterioration. HSD is also associated with a variety of psychiatric symptoms, primarily depression and mental deterioration. However, psychosis has rarely been reported as a major symptom of HSD. We report two siblings who presented psychiatric symptoms as major clinical presentations, accompanied by ataxic and spastic gait, dysarthria, and typical neuroimaging findings of HSD. A 14-year-old girl presented complex motor tics, stereotypic behavior and anxiety symptoms. Her older brother, a 16-year-old boy, presented prominent auditory hallucinations, persecutory delusions and social withdrawal symptoms. Psychiatric symptoms were improved after atypical antipsychotic treatment. HSD is a rare disease but should be carefully considered in the diagnosis of patients with both motor disorder and various psychiatric symptoms.

Clinical spectrum of Hallervorden-Spatz syndrome in India

Hallervorden-Spatz syndrome is a rare autosomal recessive disorder that involves progressive extrapyramidal manifestations. Classical and atypical clinical presentations are known. Clinical details of patients admitted to the neurology ward or attending the movement disorder clinic of the All India Institute of Medical Sciences between January 2001 and July 2007 were reviewed. Sixteen patients (9 males and 7 females) were included in the study (median age 14 years; range 6-25). The most common clinical presentation was limb or cranial onset progressive dystonia. The patients with early onset had more frequent truncal and axial dystonia, including retrocollis, oromandibular-facial dystonia and chorea, dysarthria, pyramidal signs, gait disturbance, cognitive impairment, delay in milestones, retinitis pigmentosa, optic atrophy, oculomotor abnormalities, positive family history and acanthocytosis. Although rare, cerebellar ataxia, behavioural abnormalities, parkinsonism and apraxia of eyelid opening were exclusively seen in late onset patients. The present study highlights the heterogeneity of this disease entity and also describes certain unusual clinical features.

A novel PANK2 gene mutation: clinical and molecular characteristics of patients short communication

Pantothenate kinase-associated neurodegeneration (PKAN) is a progressive neurodegenerative disorder with autosomal recessive inheritance. The major symptoms of PKAN include the onset before the age of 20 years, progressive pyramidal and extrapyramidal signs, retinitis pigmentosa, optic atrophy, dementia, and iron depositions in the globus pallidus. The authors present 3 patients with proven molecular diagnosis of PKAN, in whom 2 novel mutations of PANK2 gene have been identified.

Brain iron metabolism: neurobiology and neurochemistry

New findings obtained during the past years, especially the discovery of mutations in the genes associated with brain iron metabolism, have provided key insights into the homeostatic mechanisms of brain iron metabolism and the pathological mechanisms responsible for neurodegenerative diseases. The accumulated evidence demonstrates that misregulation in brain iron metabolism is one of the initial causes for neuronal death in some neurodegenerative disorders. The errors in brain iron metabolism found in these disorders have a multifactorial pathogenesis, including genetic and nongenetic factors. The disturbances of iron metabolism might occur at multiple levels, including iron uptake and release, storage, intracellular metabolism and regulation. It is the increased brain iron that triggers a cascade of deleterious events, leading to neuronal death in these diseases. In the article, the recent advances in studies on neurochemistry and neuropathophysiology of brain iron metabolism were reviewed.

Relaxation and susceptibility MRI characteristics in Hallervorden-Spatz syndrome

PURPOSE

To evaluate the imaging characteristics of the brain with respect to relaxation and susceptibility in Hallervorden-Spatz syndrome (HSS), a rare inherited neurodegenerative disorder (also referred to as neurodegeneration with brain iron accumulation).

MATERIALS AND METHODS

We reviewed 13 affected individuals who satisfied the inclusion criteria for HSS. Clinically, the patients were divided into two groups: early-childhood onset (age of onset before 10 years) and late-childhood onset (age of onset after 10 years). MRI was performed on 1.5T MR equipment. The imaging protocol included spin-echo (SE) T1-weighted (T1W), turbo spin-echo (TSE) T2W, and fluid attenuated inversion recovery (FLAIR) sequences in all patients. Susceptibility-weighted imaging (SWI) included a fast low-angle shot (FLASH) sequence in 10 patients and a blood oxygen level-dependent (BOLD) sequence in two patients.

RESULTS

All of the patients showed hyperintensity on T1WI and hypointensity on T2WI in the globus pallidi (GPs) bilaterally. Central or anteromedial hyperintensity was found in all but one patient. FLASH showed augmented hypointensity in 10 patients, and BOLD showed bilateral striatonigral abnormal pigmentation in two patients. MR spectroscopy (MRS) showed normal spectra in four patients, and a reduced NAA/Cho ratio in two.

CONCLUSION

MRI showed prominent signal abnormalities in the GP bilaterally in HSS. T1WI showed hyperintensity in all cases of HSS in addition to the "eye-of-the-tiger" sign on T2WI. SWI, FLASH, and BOLD demonstrated mineral deposition in the GP better than conventional imaging. Involvement of the striatonigral pathways was demonstrated for the first time on BOLD SWI.

Psychosis as presenting symptom in adult-onset Hallervorden-Spatz syndrome

BACKGROUND

Hallervorden-Spatz syndrome is characterized by pyramidal and extrapyramidal signs, and dysarthria and dementia. Psychiatric symptomatology can emerge in the course of the disorder. Mutations in the pantothenate kinase 2 gene have been found in many cases. We report a case with psychosis as sole presenting symptom.

CASE

A 41-year-old man presented with change in behavior and paranoid delusional ideation. Six months later, spasticity, extrapyramidal rigidity and dysarthria were added to the picture. Eventually, the patient became mute and wheel-chair bound. The brain magnetic resonance imaging (MRI) was consistent with iron depositions in the globus pallidus and substantia nigra.

CONCLUSIONS

In this case, the combination of clinical and MRI findings was consistent with Hallervorden-Spatz syndrome. The combination of psychiatric and MRI findings should lead to further neurological investigation.

Iron metabolism in Parkinsonian syndromes

Growing evidence suggests an involvement of iron in the pathophysiology of neurodegenerative diseases. Several of the diseases are associated with parkinsonian syndromes, induced by degeneration of basal ganglia regions that contain the highest amount of iron within the brain. The group of neurodegenerative disorders associated with parkinsonian syndromes with increased brain iron content can be devided into two groups: (1) parkinsonian syndromes associated with brain iron accumulation, including Parkinson's disease, diffuse Lewy body disease, parkinsonian type of multiple system atrophy, progressive supranuclear palsy, corticobasal ganglionic degeneration, and Westphal variant of Huntington's disease; and (2) monogenetically caused disturbances of brain iron metabolism associated with parkinsonian syndromes, including aceruloplasminemia, hereditary ferritinopathies affecting the basal ganglia, and panthotenate kinase associated neurodegeneration type 2. Although it is still a matter of debate whether iron accumulation is a primary cause or secondary event in the first group, there is no doubt that iron-induced oxidative stress contributes to neurodegeneration. Parallels concerning pathophysiological as well as clinical aspects can be drawn between disorders of both groups. Results from animal models and reduction of iron overload combined with at least partial relief of symptoms by application of iron chelators in patients of the second group give hope that targeting the iron overload might be one possibility to slow down the neurodegenerative cascade also in the first group of inevitably progressive neurodegenerative disorders.

Role of iron in neurodegenerative disorders

Although the pathophysiology underlying a number of neurodegenerative diseases is complex and, in many aspects, only partly understood, increased iron levels in pathologically relevant brain areas and iron-mediated oxidative stress seem to play a central role in many of them. Much has been learned from monogenetically caused disturbances of brain iron metabolism including pantothenate kinase-associated neurodegeneration type 2, hereditary ferritinopathies affecting the basal ganglia, and aceruloplasminemia that may well be applied to the most common neurodegenerative disorders associated with brain iron accumulation including Parkinson disease and Alzheimer disease. Iron-mediated oxidative stress in neurodegenerative diseases caused by other genetic pathways like Huntington disease and Friedreich ataxia underscore the complex interaction of this trace metal and genetic variations. Therapeutical strategies derived from application of iron chelators in monogenetically caused disturbances of brain iron metabolism and new iron and oxidative stress diminishing substances in animal models of Parkinson disease are promising and warrant further investigational effort.

Imaging dementing illnesses

Dementia is an impairment of mental ability representing a decline from that level previously reached by the individual. It is usually of insidious onset, associated with neurologic changes, and results in the inability to appropriately interact with one's environment. Dementias may be static, progressive, or reversible, and have many etiologies. One percent of the population above age 40 suffers from dementia and this figure rises to 7% above age 80 and 50% above age 90. Forty-five percent of dementias are due to Alzheimer disease (AD) followed closely by vascular dementia. A stage along the way to dementia is mild cognitive impairment (MCI). There are various definitions but the simplest ones refer to a person who has some memory problems but can continue to live independently. A more specific description refers to deficits in two or more areas of cognition >1.5 SD below mean for the individuals age and education. Although previously considered a part of normal aging, a recent study has shown MCI to be a precursor of Alzheimer disease (1). In a cohort of nuns and priests studied annually until they developed MCI or dementia and died. 180 brains in this study have already been autopsied (37 MCI, 60 with no impairment, 53 with dementia). Pathologists measured theamount of AD pathology and cerebral infarcts. Of 37 with MCI, more than half had AD by pathology, 1/3 had infarcts (5 with both) and 14 did not have either pathology. One third of the 180 with average age of 85 had no cognitive decline! Since this study showed MCI patients to have Alzheimer disease pathology in their brains, recognition of MCI clinically is important for institution of therapy, although there has not yet been an effective therapy developed.

Clinical heterogeneity in Hallervorden-Spatz syndrome: a clinicoradiological study in 13 patients from South India

Hallervorden-Spatz syndrome (HSS) is a rare autosomal recessive neurodegenerative disorder of childhood. Thirteen patients with this syndrome seen over a period of 7 years were reviewed. Two distinct groups were identified. The early onset childhood group had uniform presentation with developmental delay, recurrent falls, gait abnormalities, cognitive deterioration and dystonia. This group was also characterised by familial incidence, retinal involvement and absence of behavioural problems. Late onset group, included patients with different presentations such as behavioural changes, optic atrophy and dystonia. Consanguinity was prominent in this study, being present in 61.5% patients. MRI (n=11) showed pallidal hyperintensity on T1-weighted images and hypointensity or 'eye of the tiger' sign on T2-weighted images. Two patients had acanthocytes in peripheral blood smear. This study emphasizes the phenotypic heterogeneity in HSS and as well brings out the common features shared by patients with early onset disease.

Novel compound heterozygous mutations in the PANK2 gene in a Chinese patient with atypical pantothenate kinase-associated neurodegeneration

We investigated the presence of mutations in the pantothenate kinase (PANK2) gene in a 27-year-old male Chinese patient with atypical pantothenate kinase-associated neurodegeneration (PKAN), formerly Hallervorden-Spatz syndrome. Automated DNA sequence analyses revealed compound heterozygous mutations in the exon 3 and 5. This patient had a 10-year history of PKAN characterized by a slight tremor of the right hand when writing at onset and a slow progressive rigidity of the neck and the right arm and resting tremor in upper extremities. Dysarthria, dysphagia, and dystonic-athetoid movements of the face and right fingers were marked. Magnetic resonance showed the typical "eye-of-the-tiger" sign.

A novel 3-bp deletion in the PANK2 gene of Dutch patients with pantothenate kinase-associated neurodegeneration: evidence for a founder effect

Mutation analysis was performed in four apparently unrelated Dutch families with pantothenate kinase-associated neurodegeneration, formerly known as Hallervorden-Spatz syndrome. A novel 3-bp deletion encompassing the nucleotides GAG at positions 1,142 to 1,144 of exon 5 of the PANK2 gene was found in all patients. One patient was compound heterozygous; she also carried a novel nonsense mutation (Ser68Stop). The other patients were homozygous for the 1142_1144delGAG mutation. The 1142_1144delGAG mutation was also found in a German patient of unknown descent. We used polymorphic microsatellite markers flanking the PANK2 gene (spanning a region of approximately 8 cM) for haplotype analyses in all these families. A conserved haplotype of 1.5 cM was found for the 1142_1144delGAG mutation carriers. All the Dutch families originated from the same geographical region within the Netherlands. The results indicate a founder effect and suggest that the 1142_1144delGAG mutation probably originated from one common ancestor. It was estimated that this mutation arose at the beginning of the ninth century, approximately 38 generations ago.

Atypical Hallervorden-Spatz disease with preserved cognition and obtrusive obsessions and compulsions

We describe the case of an adult female with Hallervorden-Spatz disease (HSD), "eye-of-the-tiger" sign on cranial magnetic resonance imaging scan, and two mutations in the pantothenate kinase 2 (PANK2) gene. Symptomatic presentation included stuttering dysarthria, dystonic posturing, increased limb and axial muscle tone, choreoathetosis, stereotyped motor behaviors, and obsessive-compulsive symptomatology since adolescence. Extensive neuropsychological testing at 40 and 44 years of age revealed a relatively normal IQ and stable cognitive pattern overall. This case demonstrates that HSD patients who survive into middle age should not be assumed to have a progressive dementia. In such cases, atypical behavioral problems such as persistent obsessions and compulsions may be present instead.

Pantothenate kinase-associated neurodegeneration initially presenting as postural tremor alone in a Japanese family with homozygous N245S substitutions in the pantothenate kinase gene

We describe a 24-year-old Japanese woman with pantothenate kinase-associated neurodegeneration (PKAN) whose only early symptom was postural tremor in the right hand at around 18 years of age, leading to a diagnosis of essential tremor at age 21. Although she was treated with arotinolol hydrochloride and clonazepam, she gradually progressed to extrapyramidal and pyramidal signs several years later. T2-weighted magnetic resonance images (MRI) showed bilaterally marked hypointensity with a central region of hyperintensity in the globus pallidus, or the so-called "eye-of-the-tiger" sign. Six years have passed since the initial appearance of postural tremor, whereas she has not shown choreoathetosis, retinitis pigmentosa, optic atrophy, or seizure. Direct sequencing of the patient's genomic DNA revealed homozygous base substitutions in the pantothenate kinase gene (PANK2): the A764-->G substitution (N245S) due to consanguinity of her parents. Although the heterozygous form of this mutation has already been reported among several families, this is the first report of the homozygous mutation in a patient with atypical-type PKAN. This detailed description of the clinical features of a Japanese patient with PKAN arising from homozygous N245S mutations in PANK2 would be useful for elucidating the pathogenesis of PKAN.

Pallidal deep brain stimulation for longstanding severe generalized dystonia in Hallervorden-Spatz syndrome. Case report

Generalized dystonia is one of the most disabling movement disorders. Ablative stereotactic surgery such as pallidotomy has been performed for medically refractory dystonia. Recently, deep brain stimulation (DBS) has appeared as an alternative to ablative procedures. Nevertheless, there have been few published reports detailing improvement in dystonia with DBS. This 36-year-old man with Hallervorden-Spatz syndrome suffered from intractable primary generalized dystonia for 28 years. He was completely dependent for activities of daily living and wheelchair bound because of continuous severe dystonic movements in the face, tongue, neck, trunk, and upper and lower extremities while at rest. The Burke-Fahn-Marsden (BFM) Dystonia Rating Scale score was 112 (maximum 120 points). Bilateral DBS of the globus pallidus internus was performed and resulted in marked improvement in motor functioning and dystonic symptoms with a significant reduction in disability. The BFM score improved to 22.5 points (80% improvement) at 3 months postsurgery and the patient's dystonia was still well suppressed 1 year after surgery. Bilateral pallidal stimulation is an effective and safe treatment for intractable generalized dystonia in Hallervorden-Spatz syndrome, even if the disability is severe and longstanding.

Hereditary Causes of Disturbed Iron Homeostasis in the Central Nervous System

Iron is essential for oxidation-reduction catalysis and bioenergetics; however, unless appropriately shielded, this metal plays a crucial role in the formation of toxic oxygen radicals that can attack all biological molecules. Organisms are equipped with specific proteins designed for iron acquisition, export and transport, and storage, as well as with sophisticated mechanisms that maintain the intracellular labile iron pool at an appropriate level. Despite these homeostatic mechanisms, organisms often face the threat of either iron deficiency or iron overload. This review describes several hereditary iron-overloading conditions that are confined to the brain. Recently, a mutation in the L-subunit of ferritin has been described that causes the formation of aberrant L-ferritin with an altered C-terminus. Individuals with this mutation in one allele of L-ferritin have abnormal aggregates of ferritin and iron in the brain, primarily in the globus pallidus. Patients with this dominantly inherited late-onset disease present with symptoms of extrapyramidal dysfunction. Mice with a targeted disruption of a gene for iron regulatory protein 2 (IRP2), a translational repressor of ferritin, misregulate iron metabolism in the intestinal mucosa and the central nervous system. Significant amounts of ferritin and iron accumulate in white matter tracts and nuclei, and adult IRP2-deficient mice develop a movement disorder consisting of ataxia, bradykinesia, and tremor. Mutations in the frataxin gene are responsible for Friedreich's ataxia, the most common of the inherited ataxias. Frataxin appears to regulate mitochondrial iron-sulfur cluster formation, and the neurologic and cardiac manifestations of Friedreich's ataxia are due to iron-mediated mitochondrial toxicity. Patients with Hallervorden-Spatz syndrome, an autosomal recessive, progressive neurodegenerative disorder, have mutations in a novel pantothenate kinase gene (PANK2). The cardinal feature of this extrapyramidal disease is pathologic iron accumulation in the globus pallidus. The defect in PANK2 is predicted to cause the accumulation of cysteine, which binds iron and causes oxidative stress in the iron-rich globus pallidus. Finally, aceruloplasminemia is an autosomal recessive disorder of iron metabolism caused by loss-of-function mutations in ceruloplasmin gene that leads to misregulation of both systemic and central nervous system iron trafficking. Affected individuals suffer from extrapyramidal signs, cerebellar ataxia, progressive neurodegeneration of retina, and diabetes mellitus. Excessive iron depositions are found in the brain, liver, pancreas, and other parenchymal cells, but plasma iron concentrations are decreased. These conditions are not common, but awareness about them is important for differential diagnosis of various neurodegenerative disorders.

Psychotic disorder in a case with Hallervorden-Spatz disease

OBJECTIVE

Hallervorden-Spatz disease is a rare autosomal recessive condition, with early onset of predominantly extrapyramidal dysfunction. The symptoms of the disease are dystonia, rigidity, choreoathetosis, pyramidal signs, and intellectual decline. Recent genetic studies mapped the disease to chromosome 20p12.3-p13, and identified mutations in the pantothenate kinase gene. This report describes a childhood onset case of Hallervorden-Spatz disease with schizophreniform psychotic symptoms. Former reports about the psychiatric comorbidity generally included depressive disorder.

METHOD

A single case report.

RESULTS

A 14-year-old boy with Hallervorden-Spatz disease presented a psychotic episode with prominent auditory hallucinations. Symptoms were relieved after neuroleptic treatment.

CONCLUSION

To the authors' knowledge, this is the first published report of the disease with psychotic symptoms. The contribution of basal ganglia, with their wide projections, to the emergence of psychotic symptoms was discussed.

Clinical heterogeneity of neurodegeneration with brain iron accumulation (Hallervorden-Spatz syndrome) and pantothenate kinase-associated neurodegeneration

Hallervorden Spatz syndrome (HSS), also referred to as neurodegeneration with brain iron accumulation (NBIA), is a rare inherited neurodegenerative disorder with childhood, adolescent, or adult onset. Patients with HSS/NBIA have a combination of motor symptoms in the form of dystonia, parkinsonism, choreoathetosis, corticospinal tract involvement, optic atrophy, pigmentary retinopathy, and cognitive impairment. After the recent identification of mutations in the PANK2 gene on chromosome 20p12.3-p13 in some patients with the HSS/NBIA phenotype, the term pantothenate kinase-associated neurodegeneration (PKAN) has been proposed for this group of disorders. To characterize clinically and genetically HSS/NBIA, we reviewed 34 affected individuals from 10 different families, who satisfied the inclusion criteria for NBIA. Relatives of patients who had clinical, magnetic resonance imaging (MRI), or pathological findings of NBIA were included in the study. Four patients were found to have mutations in the pantothenate kinase 2 (PANK2) gene. We compared the clinical features and MRI findings of those with and without PANK2 mutations. The presence of mutation in the PANK2 gene is associated with younger age at onset and a higher frequency of dystonia, dysarthria, intellectual impairment, and gait disturbance. Parkinsonism is seen predominantly in adult-onset patients whereas dystonia seems more frequent in the earlier-onset cases. The phenotypic heterogeneity observed in our patients supports the notion of genetic heterogeneity in the HSS/NBIA syndrome.

Iron misregulation in the brain: a primary cause of neurodegenerative disorders

High iron concentrations in the brains of patients and the discovery of mutations in the genes associated with iron metabolism in the brain suggest that iron misregulation in the brain plays a part in neuronal death in some neurodegenerative disorders, such as Alzheimer's, Parkinson's, and Huntington's diseases and Hallervorden-Spatz syndrome. Iron misregulation in the brain may have genetic and non-genetic causes. The disrupted expression or function of proteins involved in iron metabolism increases the concentration of iron in the brain. Disturbances can happen at any of several stages in iron metabolism (including uptake and release, storage, intracellular metabolism, and regulation). Increased brain iron triggers a cascade of deleterious events that lead to neurodegeneration. An understanding of the process of iron regulation in the brain, the proteins important in this process, and the effects of iron misregulation could help to treat or prevent neurodegenerative disorders.

Childhood dystonia

Childhood dystonias are a heterogeneous group of disorders with strong inherited basis. This review describes the clinical characteristics, classification, genetic basis, pathophysiology, biochemistry, pathology, and treatment of dystonias, including the primary dystonias, the dystonia-plus syndromes, secondary dystonias, and heredodegenerative disorders. Conditions discussed in detail include idiopathic torsion dystonia, dopa-responsive dystonia, Wilson's disease, myoclonus dystonia, rapid-onset dystonia parkinsonism, neurodegeneration with brain iron accumulation (Hallervorden-Spatz syndrome), mitochondrial dystonias, Niemann-Pick type C, and neuroacanthocytosis.

Progressive dystonia in a 12-year-old boy

Pantothenate kinase-associated neurodegeneration (PKAN) (MIM 234200; Hallervorden-Spatz syndrome) is a degenerative, autosomal recessive disorder in childhood, currently without specific treatment. In contrast to variable clinical features, T2-weighted magnetic resonance images show a characteristic 'eye-of-the-tiger sign' in the globus pallidus due to excess iron deposition. Recently a defect in pantothenate kinase, the key regulatory enzyme in the synthesis of coenzyme A from pantothenate, has been identified as the cause of the disease. We report a 12-year-old boy with progressive rigidity, dystonia, impaired voluntary movement, dysarthria, and mental deterioration. Over 10 years the boy had been misdiagnosed with clumsiness, emotional and behavioural deficits, and attention deficit disorder, before neuroimaging was performed showing the characteristic 'eye-of-the-tiger sign'. Molecular analyses confirmed two mutations in the PANK2 gene [coding sequence of a gene that has homology to murine pantothenate kinase-1]. We conclude that in progressive childhood dystonia, PKAN should be considered and magnetic resonance imaging performed early. The newly described defect of the pantothenate kinase enzyme enables a novel therapeutic approach to be considered, based on the mutation analyses of the PANK2 gene, as well as the prenatal diagnosis of this disorder.

Iron in neurodegenerative disorders

Increasing evidence implicates a role of iron in the pathogenesis of numerous neurodegenerative diseases due to its capacity to enhance production of toxic reactive radicals and to induce protein aggregation. The underlying mechanism of iron accumulation in areas of the brain specific for the respective disease, however, is still unknown. Recent molecular and biochemical studies provide new insights into the consequences of impairment of brain iron metabolism. This review summarizes our understanding of the regulation of iron in the brain and defines the current knowledge on the involvement of iron metabolism in neurodegenerative diseases with genetically determined iron accumulation in the brain.

Rare causes of hereditary iron overload

Iron is a vitally important element in mammalian metabolism because of its unsurpassed versatility as a biologic catalyst. However, when not appropriately shielded or when present in excess, iron plays a key role in the formation of extremely toxic oxygen radicals, which ultimately cause peroxidative damage to vital cell structures. Organisms are equipped with specific proteins designed for iron acquisition, export, transport, and storage as well as with sophisticated mechanisms that maintain the intracellular labile iron pool at an appropriate level. These systems normally tightly control iron homeostasis but their failure can lead to iron deficiency or iron overload and their clinical consequences. This review describes several rare iron loading conditions caused by genetic defects in some of the proteins involved in iron metabolism. A dramatic decrease in the synthesis of the plasma iron transport protein, transferrin, leads to a massive accumulation of iron in nonhematopoietic tissues but virtually no iron is available for erythropoiesis. Humans and mice with hypotransferrinemia have a remarkably similar phenotype. Homozygous defects in a recently identified gene encoding transferrin receptor 2 lead to iron overload (hemochromatosis type 3) with symptoms similar to those seen in patients with HFE-associated hereditary hemochromatosis (hemochromatosis type 1). Transferrin receptor 2 is primarily expressed in the liver but it is unclear how mutant forms cause iron overload. Mutations in the gene encoding the iron exporter, ferroportin 1, cause iron overload characterized by iron accumulation in macrophages yet normal plasma iron levels. Plasma iron, together with dominant inheritance, discriminates iron overload due to ferroportin mutations (hemochromatosis type 4) from hemochromatosis type 1. Heme oxygenase 1 is essential for the catabolism of heme and in the recycling of hemoglobin iron in macrophages. Homozygous heme oxygenase 1 deletion in mice leads to a paradoxical accumulation of nonheme iron in macrophages, hepatocytes, and many other cells and is associated with low plasma iron levels, anemia, endothelial cell damage, and decreased resistance to oxidative stress. A similar phenotype occurred in a child with severe heme oxygenase 1 deficiency. Recently, a mutation in the L-subunit of ferritin has been described that causes the formation of aberrant L-ferritin with an altered C-terminus. Individuals with this mutation in one allele of L-ferritin have abnormal aggregates of ferritin and iron in the brain, primarily in the globus pallidus. Patients with this dominantly inherited late-onset disease present with symptoms of extrapyramidal dysfunction. Mice with a targeted disruption of a gene for iron regulatory protein 2 (IRP2), a translational repressor of ferritin, misregulate iron metabolism in the intestinal mucosa and the central nervous system. Significant amounts of ferritin and iron accumulate in white matter tracts and nuclei, and adult IRP2-deficient mice develop a movement disorder consisting of ataxia, bradykinesia, and tremor. Mutations in the frataxin gene are responsible for Friedreich ataxia, the most common of the inherited ataxias. Frataxin appears to regulate mitochondrial iron (or iron-sulfur cluster) export and the neurologic and cardiac manifestations of Friedreich ataxia are due to iron-mediated mitochondrial toxicity. Finally, patients with Hallervorden-Spatz syndrome, an autosomal recessive, progressive neurodegenerative disorder, have mutations in a novel pantothenate kinase gene (PANK2). The cardinal feature of this extrapyramidal disease is pathologic iron accumulation in the globus pallidus. The defect in PANK2 is predicted to cause the accumulation of cysteine, which binds iron and causes oxidative stress in the iron-rich globus pallidus.

Neurologic manifestations of iron deficiency in childhood

Iron deficiency is a common disorder in pediatric patients. Although the most common manifestation is that of anemia, iron deficiency is frequently the source of a host of neurologic disorders presenting to general pediatric neurologic practices. These disorders include developmental delay, stroke, breath-holding episodes, pseudotumor cerebri, and cranial nerve palsies. Although frequent, the identification of iron deficiency as part of the differential diagnosis in these disorders is uncommon and frequently goes untreated. The purpose of the current review is to highlight what is understood regarding iron deficiency and it's underlying pathophysiology as it relates to the brain, and the association of iron deficiency with common neurologic pediatric disease.