Atypical Pantothenate Kinase-associated Neurodegeneration Research Articles

Feeding Dystonia as an Unusual Presentation for Atypical Pantothenate Kinase-associated Neurodegeneration (PKAN) in a Patient with Novel PANK2 Mutations (P8-3.006)

Feeding Dystonia as an Unusual Presentation for Atypical Pantothenate Kinase-associated Neurodegeneration (PKAN) in a Patient with Novel PANK2 Mutations (P8-3.006)

Novel utilization of deep brain stimulation in the pedunculopontine nucleus with globus pallidus internus for treatment of childhood-onset dystonia

IntroductionDeep brain stimulation (DBS) is a well-documented therapy for dystonia utilized in many adult and pediatric movement disorders. Pedunculopontine nucleus (PPN) has been investigated as a DBS target primarily in adult patients with dystonia or dyskinesias from Parkinson’s disease, showing improvement in postural instability and gait dysfunction. Due to the difficulty in targeting PPN using standard techniques, it is not commonly chosen as a target for adult or pediatric pathology. There is no current literature describing the targeting of PPN in DBS for childhood-onset dystonia.MethodsTwo pediatric and one young adult patient with childhood-onset dystonia who underwent DBS implantation at our institution were identified. Patient 1 has Mitochondrial Enoyl CoA Reductase Protein-Associated Neurodegeneration (MEPAN) syndrome. Patient 2 has Glutaric Aciduria Type 1 (GA1). Patient 3 has atypical pantothenate kinase-associated neurodegeneration (PKAN). PPN was identified as a potential target for these patients due to axial or orofacial dystonia. Pre- and post-operative videos taken as part of routine clinical assessments were evaluated and scored on the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Barry-Albright Dystonia Scale (BADS). All patients had permanent electrodes placed bilaterally in PPN and globus pallidus internus (GPi). A Likert scale on quality of life was also obtained from the patient/parents as applicable.ResultsSignificant programming was necessary over the first 3–12 months to optimize patients’ response to stimulation. All patients experienced at least a 34% improvement in the BFMDRS score. Patients 2 and 3 also experienced an over 30% improvement in BADS score. All patients/parents appreciated improvement in quality of life postoperatively.DiscussionDeep brain stimulation in PPN was safely and successfully used in two pediatric patients and one young adult patient with childhood-onset dystonia. These patients showed clinically significant improvements in BFMDRS scoring post operatively. This represents the first reported DBS targeting of PPN in pediatric patients, and suggests that PPN is a possible target for pediatric-onset dystonia with axial and orofacial symptoms that may be refractory to traditional pallidal stimulation alone.

Diagnosis and Treatment of Pantothenate Kinase-Associated Neurodegeneration (PKAN): A Systematic Review.

A specific type of neurodegeneration with brain iron accumulation (NBIA) falls under the omit phenotypic continuum-early childhood development of progressive pantothenate kinase-associated neurodegeneration (PKAN). Classic PKAN is distinguished from atypical PKAN by stiffness, dystonia, dysarthria, and choreoathetosis. Pigmentary retinal degeneration is a widespread cause of classic PKAN. Atypical PKAN is distinguished by a later onset (>10 years), noticeable speech abnormalities, psychological disorders, and slower disease development. Studies designed to support various PKANtherapeutic strategies have highlighted the intricacy of coenzyme A (CoA) metabolism and the limitations of our present understanding of disease causation. Therefore, improvements in our knowledge of the causes and therapy of PKAN may have ramifications for our comprehension of other, more prevalent diseases. They may also shed fresh light on the physiological significance of CoA, a cofactor essential for the operation of several cellular metabolic processes. The existence of low but considerable PANK2 expression, which can be elevated in some mutations, provides necessary information that can justify using a hefty dose of pantothenate as a treatment. A more effective therapeutic approach can be achieved by comparing the effects of various currently available pharmacological alternatives on the pathophysiological alterations in fibroblasts and neuronal cells obtained from PKAN patients. The objective of this study is to educate and inform people about PKAN disease conditions such as treatment, diagnosis, and complications. These cell models will also help evaluate the effectiveness of future medicinal innovations. This review discusses the neurodegeneration generated by pantothenate kinase in cellular models, iron/lipofuscin in pantothenate kinase-related neurodegeneration, and treatment and diagnosis of PKAN.

Patient and caregiver experiences with pantothenate kinase-associated neurodegeneration (PKAN): results from a patient community survey

BackgroundPantothenate kinase-associated neurodegeneration (PKAN) is a rare autosomal recessive genetic disorder of PANK2, which enables mitochondrial synthesis of coenzyme A. Its loss causes neurodegeneration with iron accumulation primarily in motor-related brain areas. Symptoms include dystonia, parkinsonism, and other disabilities. PKAN has been categorized as classic PKAN, with an age of onset ≤ 10 years, rapid progression, and early disability or death; and atypical PKAN, with later onset, slower progression, generally milder, and more diverse symptom manifestations. Available treatments are mostly palliative. Information on the lived experience of patients with PKAN and their caregivers or on community-level disease burden is limited. It is necessary to engage patients as partners to expand our understanding and improve clinical outcomes. This patient-oriented research study used multiple-choice and free-form question surveys distributed by patient organizations to collect information on the manifestations and disease burden of PKAN. It also assessed respondents’ experiences and preferences with clinical research to inform future clinical trials.ResultsThe analysis included 166 surveys. Most respondents (87%) were parents of a patient with PKAN and 7% were patients, with 80% from Europe and North America. The study cohort included 85 patients with classic PKAN (mean ± SD age of onset 4.4 ± 2.79 years), 65 with atypical PKAN (13.8 ± 4.79 years), and 16 identified as “not sure”. Respondents reported gait disturbances and dystonia most often in both groups, with 44% unable to walk. The classic PKAN group reported more speech, swallowing, and visual difficulties and more severe motor problems than the atypical PKAN group. Dystonia and speech/swallowing difficulties were reported as the most challenging symptoms. Most respondents reported using multiple medications, primarily anticonvulsants and antiparkinsonian drugs, and about half had participated in a clinical research study. Study participants reported the most difficulties with the physical exertion associated with imaging assessments and travel to assessment sites.ConclusionsThe survey results support the dichotomy between classic and atypical PKAN that extends beyond the age of onset. Inclusion of patients as clinical research partners shows promise as a pathway to improving clinical trials and providing more efficacious PKAN therapies.

Intellectual Disability, Falls and Gait Disturbances: A Misdiagnosis.

We report the case of a 27-year-old man presenting with slowly progressive extrapyramidal dysfunction and learning disability considered to have a syndromic intellectual disability. The re-evaluation of the clinical features and the investigations performed led to the diagnosis of atypical pantothenate kinase-associated neurodegeneration (PKAN).LEARNING POINTSPatients with an intellectual disability should be carefully evaluated.In the evaluation of a patient with extrapyramidal dysfunction for several years, with gradual progression, spasticity and psychiatric disturbances, PKAN should be considered.

Novel PANK2 mutation identified in patient with pantothenate kinase-associated neurodegeneration

Introduction. Pantothenate kinase-associated neurodegeneration (PKAN) is a rare, recessively inherited disorder caused by mutations in the pantothenate kinase 2 (PANK2) gene on chromosome 20p13. The objective of this report is to present a patient with atypical PKAN with the novel heterozygous PANK2 mutation. Case outline. We present a 32-year-old female who had disease onset at the age 20 (depression, speech, chewing problems and backward falls) with progressive course. Neurological examination revealed hypomimia, risus sardonicus, dysphagia, tachylalia and severe dystonic dysarthria, moderate arms, legs, and jaw-opening dystonia, postural instability, urge incontinence, and decreased visual acuity. Brain magnetic resonance imaging revealed iron accumulation in the bilateral globus pallidus and putamen (?eye-of-the-tiger?), a radiological finding pathognomonic for PKAN. Genetic analysis revealed known mutation p.T528M (c.1583C>T) in exon 6, and novel p.Y405D (c.1213T>G) in exon 3 of the PANK2 gene. In silico analyses strongly suggested this mutation to be pathogenic. Conclusion. We report a patient with PKAN, and novel substitution p.Y405D (c.1213T>G) in PANK2 that has not been previously described in PKAN patients.

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

Aim: Pantothenate-kinase-associated neurodegeneration (PKAN), which is characterised by iron accumulation in the basal ganglia, is a rare autosomal recessive neurodegenerative disorder caused by pantothenate kinase 2 (PANK2) gene mutations. The PANK2 gene is located on chromosome 20p13 and encodes pantothenate kinase. Herein, we identified one patient with PKAN who had mutations in the PANK2 gene.Materials and methods: We performed clinical and radiographic investigations, and diagnosed this disease at the clinical and genetic levels.Results: It is worth mentioning that the patient displayed an eye-of-the-tiger sign. Through scanning the exons and flanking intronic sequences of PANK2 in patient and control subjects, we report a compound heterozygote c. 260A > G (NM_001324191) and c.405dupC (NM_153638) for PANK2 mutations in a Chinese patient with clinical manifestation of progressive prosopospasm, dysarthria and gait disturbance. Bioinformatics analysis showed that two variants exhibited highly conserved residues across species.Conclusion: we reported a patient presenting with atypical PKAN, and identified novel compound heterozygous PANK2 gene mutations..

Subthalamic Nuclei Stimulation in Patients With Pantothenate Kinase-Associated Neurodegeneration (PKAN)

Pantothenate kinase-associated neurodegeneration (PKAN) is a rare autosomal recessive genetic disease that leads to extrapyramidal symptoms, such as dystonia, ataxia, dysarthria, and involuntary movements. Treatment of PKAN with deep brain stimulation (DBS) has been reported, but mainly focuses on targeting the globus pallidus internus (GPi). Subthalamic nuclei (STN) may also be a potential target for treatment of PKAN. In this study, we reviewed three patients with PKAN (two with typical PKAN and one with atypical PKAN) treated by bilateral STN stimulation and present a review of the literature. All patients received neurological evaluation using the Burke-Fahn-Marsden Dystonia Rating Scale-movement (BFMDRS) scoring system before and after surgery. Patients were then subject to regular clinical follow-ups (ranging from 22 to 44 months). The mean stimulation amplitude, pulse width and frequency was 2.65 ± 0.45 V, 91.7 ± 21.9 μs, and 146.7 ± 12.5 Hz, respectively. BFMDRS scores were improved in all patients after surgery, ranging from 41.6 to 73.1%. Improvements of appendicular symptoms ranged from 46.2 to 94.1%, and improvements of axial symptoms ranged from 27.3 to 33.3%. No side effects were reported in patients 1 and 2; whereas patient 3 exhibited a mild decline in verbal fluency one year after surgery. STN stimulation could serve as a candidate DBS target in the treatment of PKAN, especially for patients with prominent appendicular symptoms.

Atypical pantothenate kinase-associated neurodegeneration: Clinical description of two brothers and a review of the literature

Two clinical forms of pantothenate kinase-associated neurodegeneration (PKAN) have been described: typical PKAN and atypical PKAN. Atypical PKAN has later onset and a slower course of disease. This report describes two siblings with the atypical form of PKAN, combining dystonia, irritability and a dysmorphia syndrome. In addition, a review of the literature was carried out for all published cases of atypical PKAN to gather descriptions of its various clinical presentations, age of onset and MRI findings, and to highlight the different treatments used for PKAN patients.

Clinical Heterogeneity of Atypical Pantothenate Kinase-Associated Neurodegeneration in Koreans.

ObjectiveNeurodegeneration with brain iron accumulation (NBIA) represents a group of inherited movement disorders characterized by iron accumulation in the basal ganglia. Recent advances have included the identification of new causative genes and highlighted the wide phenotypic variation between and within the specific NBIA subtypes. This study aimed to investigate the current status of NBIA in Korea.MethodsWe collected genetically confirmed NBIA patients from twelve nationwide referral hospitals and from a review of the literature. We conducted a study to describe the phenotypic and genotypic characteristics of Korean adults with atypical pantothenate kinase-associated neurodegeneration (PKAN).ResultsFour subtypes of NBIA including PKAN (n = 30), PLA2G6-related neurodegeneration (n = 2), beta-propeller protein-associated neurodegeneration (n = 1), and aceruloplasminemia (n = 1) have been identified in the Korean population. The clinical features of fifteen adults with atypical PKAN included early focal limb dystonia, parkinsonism-predominant feature, oromandibular dystonia, and isolated freezing of gait (FOG). Patients with a higher age of onset tended to present with parkinsonism and FOG. The p.R440P and p.D378G mutations are two major mutations that represent approximately 50% of the mutated alleles. Although there were no specific genotype-phenotype correlations, most patients carrying the p.D378G mutation had a late-onset, atypical form of PKAN.ConclusionsWe found considerable phenotypic heterogeneity in Korean adults with atypical PKAN. The age of onset may influence the presentation of extrapyramidal symptoms.

Missions of <italic>Journal of Movement Disorders</italic>

Rapid advances in communication and information technologies have made available the clinical data of diverse ethnic and cultural populations around the world, lending them clinical relevance in neurology practice. Despite the growing need to understand clinical and epidemiological differences among various populations, competition among journals to increase citation and impact factor has hindered the publication of diverse regional data, which usually lags behind the publication of novel findings. As its aim and scope, the Journal of Movement Disorders is interested in publishing clinical studies of Parkinson’s disease and other movement and neurodegenerative disorders in Asian-Oceanian populations. It is our mission to serve as a platform to broaden the knowledge of these fields and to enhance patient care by sharing clinical and epidemiological data from various regions with the global health care community. An article reporting the genotypes and phenotypes of Korean patients affected by neurodegeneration with brain iron accumulation (NBIA), published in the current issue, is of interest in this regard. NBIA is a group of inherited disorders that share clinical features such as extrapyramidal movement disorders, varying degrees of intellectual disability, and abnormal iron deposition in the basal ganglia [1]. At present, causative genes for ten forms of NBIA have been identified. Lee et al. [2] analyzed genetically confirmed cases of NBIA from 12 referral hospitals in Korea and reported clinical findings for patients with atypical pantothenate kinase-associated neurodegeneration (PKAN). The data of Korean patients with atypical PKAN differ from those of the Caucasian population in terms of clinical manifestations and mutation hot spots. These researchers found considerable phenotypic heterogeneity ranging from isolated freezing of the gait to generalized dystonia with concurrent parkinsonism. The age of onset tended to affect the presentation of extrapyramidal symptoms in atypical PKAN. Translational research transfers knowledge from basic research to clinical research, and transfers findings from clinical studies or clinical trials to practice settings and communities, with the goal of improving health [3]. In this issue, Journal of Movement Disorders is launching a new section entitled “Translational Research Review”. This section will cover current translational research on interesting topics in Parkinson’s disease and neurodegenerative disorders. Diverse new disciplines in clinical neurology and neuroscience such as molecular neuroimaging, magnetic resonance imaging techniques, bioinformatics, and systems biology will also be covered. In this issue, Lee and Lee [4] provide an article entitled “The mechanism of anti-α-synuclein immunotherapy”. This article provides up-to-date information regarding our pathogenic and therapeutic understanding of α-synuclein. Over the past two years, the editorial team at Journal of Movement Disorders has tried improve the quality and stature of the publication. One of our missions is to make our articles readily available worldwide free of charge. Pursuing this mission has been expedited by indexing the Journal of Movement Disorders in PubMed Central. As a result, the citation of articles published in our journal has been on the rise. Moreover, our policy of maintaining an open access journal without article processing fees or page charges will facilitate the dissemination of knowledge published in the Journal of Movement Disorders. Our efforts to index the Journal of Movement Disorders in other journal databases, such as SCOPUS and Web of Science, are ongoing. We would like to thank our sponsoring organization, the Korean Movement Disorders Society, for providing financial support to continue pursuing our mission. We hope that readers of the Journal of Movement Disorders find our articles informative and valuable.

Pattern of disease progression in atypical form of pantothenate-kinase-associated neurodegeneration (PKAN) - Prospective study.

Classic form of pantothenate-kinase-associated neurodegeneration (PKAN), caused by mutation in PANK2 gene, is characterized by early onset, severe neurological impairment and rapid disease progression. In less precisely described form of atypical PKAN, clinical course is associated with late onset, less severe motor impairment and slower disease evolution. The aim of this study was to assess a pattern of disease progression in atypical PKAN, by following development of specific milestones. The clinical characteristics and the disease course of 9 genetically confirmed patients with atypical form of PKAN were evaluated. Time latencies from the disease onset to the appearance of specific clinical milestones were estimated in order to assess the disease progression. Most frequent disease presentation in our patients was characterized with early and prominent oromandibular dystonia (OMD), followed by severe generalized dystonia and early loss of mobility within the first five years of prolonged disease duration (18.7±10.0 years). Eight out of 9 patients reached 7 significant clinical milestones (OMD, generalized dystonia, dysarthria, dysphagia, postural instability, gait difficulties, ADL dependency) in the first 4.6 years of disease course. Afterwards, a long-lasting, relatively stable period of slower progression was complicated predominantly with skeletal deformities (developed after 7.0±2.8 years). Majority of milestones which might significantly influence functional abilities and quality of life in patients with atypical form of PKAN developed in the course of the first five years of the disease, followed by a long-lasting, relatively stable period of slower progression.

Novel homozygous PANK2 mutation causing atypical pantothenate kinase-associated neurodegeneration (PKAN) in a Cypriot family

Pantothenate kinase-associated neurodegeneration (PKAN) is the commonest, recessively inherited form of neurodegeneration with brain iron accumulation (NBIA) resulting from mutations in the pantothenate kinase 2 (PANK2) gene on chromosome 20. PKAN is usually rapidly progressive, presenting in the vast majority in the first decade of life (classic form). A rarer, later onset and slowly progressive (atypical) PKAN form also exists. We present two siblings of Cypriot descent, a 27-year-old man and his clinically asymptomatic younger sister, both of whom were found to be homozygous for a novel c.695A>G (p.Asp232Gly) missense mutation in exon 2 of the PANK2 gene. The index patient presented with a 5-year history of slowly progressive gait disturbance, dysarthria, mild axial rigidity and bradykinesia. His brain MRI scan revealed the characteristic “eye-of-the-tiger” sign. Atypical genetically confirmed PKAN cases are sparsely reported and should be considered in the differential diagnosis of patients presenting with a progressive extrapyramidal syndrome particularly if the radiographic findings are suggestive of iron accumulation. Effective treatment strategies for PKAN are not currently available and symptomatic therapy is often unsatisfactory. However, early diagnosis including the presymptomatic stage is important for genetic counseling and will be crucial for testing novel therapeutics in the future.

Treatment of Classic Pantothenate Kinase–Associated Neurodegeneration with Deferiprone and Intrathecal Baclofen

Neurodegeneration with brain iron accumulation (NBIA) describes a heterogeneous family of diseases characterized by high brain iron, particularly in the basal ganglia. The most common manifestation of childhood NBIA is classic pantothenate kinase-associated neurodegeneration (PKAN), a severe, progressive type of autosomal recessive neuroaxonal dystrophy characterized by early onset of symptoms (as opposed to atypical PKAN, with an average age of onset of 14 yrs). There is currently no established therapy for the disease. Intrathecal baclofen has been reported to improve ease of care and dystonia in patients with PKAN. Deferiprone, an iron chelator, has been shown to be safe and tolerable in patients with PKAN as well as effective in reducing brain iron accumulation, as measured by magnetic resonance imaging. This case report highlights the potency of combining intrathecal baclofen and oral deferiprone in a patient with classic PKAN. Although treatment with deferiprone alone was not attempted, this combination therapy seems to be more efficacious than treatment with only intrathecal baclofen.

Novel PANK2 gene mutations in two Chinese siblings with atypical pantothenate kinase-associated neurodegeneration

Pantothenate kinase-associated neurodegeneration (PKAN) is an autosomal-recessive disorder characterized by neurodegeneration and iron accumulation in the brain. Classic and atypical PKAN are distinguished on the basis of age at onset and disease progression. PANK2, localized on chromosome20p13, is confirmed as the responsible gene. We report two Chinese siblings with atypical PKAN, who had a 26- and 24-year disease course, respectively. Brain MRI scans of the two siblings showed the specific "eye of the tiger" sign. Genetic analysis identified novel compound heterozygous mutations (IVS1-2 A>T, c.T1130C) in PANK2 gene, which were confirmed to be deleterious. We verify the clinical heterogeneity even in siblings with identical genotype and expand the gene mutation pool for PKAN.

Pantothenate kinase‐associated neurodegeneration in Korea: recurrent R440P mutation in PANK2 and outcome of deep brain stimulation

The purpose of this study was to evaluate the mutation status of PANK2 among Korean patients with pantothenate kinase-associated neurodegeneration (PKAN) and to document the outcome of pallidal deep brain stimulation (DBS). Direct sequencing and deletion/duplication analysis of PANK2 were conducted in 12 patients (11 unrelated) with PKAN, diagnosed on the basis of extrapyramidal dysfunction and the 'eye-of-the-tiger sign' on brain magnetic resonance imaging (MRI). Pallidal DBS was conducted in four patients, and the outcomes were measured using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). A PANK2 mutation was identified in both alleles in all patients. The most prevalent mutation was c.1319G>C (p.R440P) in 8/22 mutated alleles (36%). An intragenic deletion ranging from exons 2 to 4 was found in one allele (1/22, 4.5%) using deletion/duplication analysis. The outcome of pallidal DBS was favorable in two patients with atypical PKAN and moderate severity of dystonia. However, two patients with typical PKAN and relatively severe symptoms showed variable responses. The c.1319G>C (p.R440P) mutation appears to be a founder genotype among Korean patients with PKAN. Furthermore, this study provides additional data for the recent international effort to evaluate the efficacy of pallidal DBS in the treatment of patients with PKAN.

Novel compound heterozygous mutations in the pantothenate kinase 2 gene in a korean patient with atypical pantothenate kinase associated neurodegeneration.

Pantothenate kinase-associated neurodegeneration (PKAN) is an autosomal recessive disorder that is characterized by mutations in the pantothenate kinase 2 gene (PANK2) and typical magnetic resonance imaging findings. We report a case of atypical PKAN presenting with generalized dystonia. Our patient had compound heterozygous mutations in the PANK2 gene, including mutation in exon 3 (p.D268G) and exon 4 (p.R330P). To our knowledge, this patient is the first to have the p.R330P mutation and the second to have the p.D268G mutation.

A Novel PANK2 Mutation in a Patient with Atypical Pantothenate-Kinase-Associated Neurodegeneration Presenting with Adult-Onset Parkinsonism

BackgroundPantothenate-kinase-associated neurodegeneration (PKAN) is an autosomal recessive neurodegenerative disorder that is characterized by progressive extrapyramidal signs, visual loss, and cognitive impairment. PKAN is caused by mutations in the pantothenate kinase gene (PANK2), which is located on chromosome 20p13 and encodes pantothenate kinase, the key regulatory enzyme in coenzyme-A biosynthesis.Case ReportIn this report we describe a case of atypical PKAN with a novel PANK2 mutation, presenting with a 10-year history of postural tremor involving both hands. Upon neurological examination, the patient's face was masked and he spoke in a monotonous voice. The patient presented with mild bradykinesia and rigidity that involved all of the extremities. Horizontal saccadic eye movements were slow and fragmented. Brain MRI revealed a typical "eye-of-the-tiger" sign. A mutation analysis revealed three PANK2 mutations: two in exon 3 (Asp 378Gly and Leu385CysfsX13) and one in exon 4 (Arg440Pro).ConclusionsParkinsonism is not an unusual presenting symptom in patients with atypical PKAN, and so it is important for physicians to consider PKAN in the differential diagnosis of patients presenting with young-onset parkinsonism.

Genetic heterogeneity in patients with pantothenate kinase–associated neurodegeneration and classic magnetic resonance imaging eye‐of‐the‐tiger pattern

We performed a detailed molecular study in two unrelated families with pantothenate kinase-associated neurodegeneration (PKAN) and the specific magnetic resonance imaging (MRI) eye-of-the-tiger pattern. In the first family with classic PKAN, linkage analysis using polymorphic markers from the PANK2 region ruled out linkage with this locus, and no mutation of the PANK2 gene was found. In the second family with atypical PKAN, we identified a novel homozygous C-to-T transition at nucleotide 1069 of the PANK2 gene, which resulted in an arginine to tryptophane substitution at codon 357. As far as we are aware, this is the first case of classic PKAN with the specific MRI eye-of-the-tiger pattern not carrying a PANK2 mutation. Therefore, the present observation reinforces the notion of the phenotypic and genetic heterogeneity in PKAN.

The diverse phenotype and genotype of pantothenate kinase-associated neurodegeneration

Pantothenate kinase-associated neurodegeneration (PKAN) is a rare autosomal-recessive disorder caused by mutations in the PANK2 gene. The authors report clinical and genetic findings of 16 patients with PKAN. The authors identified 12 mutations in the PANK2 gene, five of which were new. Only nine patients could be classified as classic or atypical PKAN, and intermediate phenotypes are described. Two patients presented with motor tics and obsessive-compulsive behavior suggestive of Tourette syndrome.