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The well‐known eye‐of‐the‐tiger sign features bilateral and symmetrical changes in the globus pallidus, with a central area of high signal and peripheral low signal on T2‐weighted MRI. Although formally considered pathognomonic of pantothenate kinase‐associated neurodegeneration (PKAN), there are other neurodegenerative or genetic diseases showing similar findings. Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) is a late‐onset ataxia, that was recently associated with biallelic AAGGG repeat expansion in the RFC1 gene. Although its predominant MRI finding is cerebellar atrophy, there may be other less common associated findings. Our aim is to present two cases of CANVAS with associated (pseudo‐)eye‐of‐the‐tiger sign, highlighting the possibility of yet another differential diagnosis for this imaging sign. [ABSTRACT FROM AUTHOR]

Abstract Background Neurodegeneration with brain iron accumulation (NBIA) disorders are a group of neurodegenerative diseases that have in common the accumulation of iron in the basal nuclei of the brain which are essential components of the extrapyramidal system. Frequent symptoms are progressive spasticity, dystonia, muscle rigidity, neuropsychiatric symptoms, and retinal degeneration or optic nerve atrophy. One of the most prevalent subtypes of NBIA is Pantothenate kinase-associated neurodegeneration (PKAN). It is caused by pathogenic variants in the gene of pantothenate kinase 2 (PANK2) which encodes the enzyme responsible for the first reaction on the coenzyme A (CoA) biosynthesis pathway. Thus, deficient PANK2 activity induces CoA deficiency as well as low expression levels of 4′-phosphopantetheinyl proteins which are essential for mitochondrial metabolism. Methods This study is aimed at evaluating the role of alpha-lipoic acid (α-LA) in reversing the pathological alterations in fibroblasts and induced neurons derived from PKAN patients. Iron accumulation, lipid peroxidation, transcript and protein expression levels of PANK2, mitochondrial ACP (mtACP), 4′′-phosphopantetheinyl and lipoylated proteins, as well as pyruvate dehydrogenase (PDH) and Complex I activity were examined. Results Treatment with α-LA was able to correct all pathological alterations in responsive mutant fibroblasts with residual PANK2 enzyme expression. However, α-LA had no effect on mutant fibroblasts with truncated/incomplete protein expression. The positive effect of α-LA in particular pathogenic variants was also confirmed in induced neurons derived from mutant fibroblasts. Conclusions Our results suggest that α-LA treatment can increase the expression levels of PANK2 and reverse the mutant phenotype in PANK2 responsive pathogenic variants. The existence of residual enzyme expression in some affected individuals raises the possibility of treatment using high dose of α-LA.

To report a case of concurrent pantothenate kinase-associated neurodegeneration (PKAN) and oculocutaneous albinism (OCA) with dual PANK2 and OCA2 variants in a Chinese patient who presented with early-onset reduced vision, nyctalopia, and neurological symptoms. Based on the ocular phenotype and provisional diagnosis of rod-cone dystrophy, genetic testing was pursued. Peripheral blood DNA extraction was carried out with the next-generation sequencing technique, which involved a population-specific medical exome virtual panel. Pre- and post-test counseling were carried out by clinical geneticists. Homozygous missense variants in PANK2 {NM_153638.3}:c.655 G>A (p.(Gly219Ser)) and OCA2{NM_025160.6}:c.1327 G>A(p.(Val443Ile)) were identified. The molecular diagnoses of pantothenate kinase associated neurodegeneration (OMIM#234200) and albinism, oculocutaneous, type II (OMIM#203200) were supported by clinical findings. Two rare autosomal recessive diseases, pantothenate kinase-associated neurodegeneration (PKAN) and oculocutaneous albinism (OCA) were detected in our patient. Ocular and systemic manifestations, as well as neuroimaging findings were compatible with the diseases identified. Genetic analysis is imperative in making an accurate molecular diagnosis in these rare conditions to allow timely counseling, disease prognostication and management. [ABSTRACT FROM AUTHOR]

Pantothenate kinase-associated neurodegeneration (PKAN) is a rare genetic neurodegenerative disorder with brain iron accumulation characterized as dysarthria, spasticity, cognitive impairment, parkinsonism, and retinopathy. PKANis caused by biallelic mutations in the mitochondrial pantothenate kinase 2 (PANK2) gene. Herein, we report a 4-year-old patient with PKAN froma Han Chinese family, who presented with developmental regression, progressive inability to walk, and limb tremors. Neuroimaging demonstrated "eye-of-the-tiger" sign. Whole exome sequencing (WES) identified compound heterozygous mutations of c.1213T>G (p. Tyr405Asp) and c.1502T>A (p.Ile501Asn) in PANK2 gene. In addition, a review of all known PANK2 variants observed in reported PKAN patients was conducted, to improve understanding of the genotype-phenotype associations that occur in PKAN patients. [ABSTRACT FROM AUTHOR]

Background: Neurodegeneration with brain iron accumulation (NBIA) disorders are a group of neurodegenerative diseases that have in common the accumulation of iron in the basal nuclei of the brain which are essential components of the extrapyramidal system. Frequent symptoms are progressive spasticity, dystonia, muscle rigidity, neuropsychiatric symptoms, and retinal degeneration or optic nerve atrophy. One of the most prevalent subtypes of NBIA is Pantothenate kinase-associated neurodegeneration (PKAN). It is caused by pathogenic variants in the gene of pantothenate kinase 2 (PANK2) which encodes the enzyme responsible for the first reaction on the coenzyme A (CoA) biosynthesis pathway. Thus, deficient PANK2 activity induces CoA deficiency as well as low expression levels of 4′-phosphopantetheinyl proteins which are essential for mitochondrial metabolism. Methods: This study is aimed at evaluating the role of alpha-lipoic acid (α-LA) in reversing the pathological alterations in fibroblasts and induced neurons derived from PKAN patients. Iron accumulation, lipid peroxidation, transcript and protein expression levels of PANK2, mitochondrial ACP (mtACP), 4′′-phosphopantetheinyl and lipoylated proteins, as well as pyruvate dehydrogenase (PDH) and Complex I activity were examined. Results: Treatment with α-LA was able to correct all pathological alterations in responsive mutant fibroblasts with residual PANK2 enzyme expression. However, α-LA had no effect on mutant fibroblasts with truncated/incomplete protein expression. The positive effect of α-LA in particular pathogenic variants was also confirmed in induced neurons derived from mutant fibroblasts. Conclusions: Our results suggest that α-LA treatment can increase the expression levels of PANK2 and reverse the mutant phenotype in PANK2 responsive pathogenic variants. The existence of residual enzyme expression in some affected individuals raises the possibility of treatment using high dose of α-LA. [ABSTRACT FROM AUTHOR]

Abstract Background Neurodegeneration with brain iron accumulation (NBIA) is a group of rare neurogenetic disorders frequently associated with iron accumulation in the basal nuclei of the brain characterized by progressive spasticity, dystonia, muscle rigidity, neuropsychiatric symptoms, and retinal degeneration or optic nerve atrophy. Pantothenate kinase-associated neurodegeneration (PKAN) is one of the most widespread NBIA subtypes. It is caused by mutations in the gene of pantothenate kinase 2 (PANK2) that result in dysfunction in PANK2 enzyme activity, with consequent deficiency of coenzyme A (CoA) biosynthesis, as well as low levels of essential metabolic intermediates such as 4′-phosphopantetheine, a necessary cofactor for essential cytosolic and mitochondrial proteins. Methods In this manuscript, we examined the therapeutic effectiveness of pantothenate, panthetine, antioxidants (vitamin E and omega 3) and mitochondrial function boosting supplements (L-carnitine and thiamine) in mutant PANK2 cells with residual expression levels. Results Commercial supplements, pantothenate, pantethine, vitamin E, omega 3, carnitine and thiamine were able to eliminate iron accumulation, increase PANK2, mtACP, and NFS1 expression levels and improve pathological alterations in mutant cells with residual PANK2 expression levels. Conclusion Our results suggest that several commercial compounds are indeed able to significantly correct the mutant phenotype in cellular models of PKAN. These compounds alone or in combinations are of common use in clinical practice and may be useful for the treatment of PKAN patients with residual enzyme expression levels.

Abstract Background Pantothenate kinase (PANK) is the first and rate-controlling enzymatic step in the only pathway for cellular coenzyme A (CoA) biosynthesis. PANK-associated neurodegeneration (PKAN), formerly known as Hallervorden–Spatz disease, is a rare, life-threatening neurologic disorder that affects the CNS and arises from mutations in the human PANK2 gene. Pantazines, a class of small molecules containing the pantazine moiety, yield promising therapeutic effects in an animal model of brain CoA deficiency. A reliable technique to identify the neurometabolic effects of PANK dysfunction and to monitor therapeutic responses is needed. Methods We applied 1H magnetic resonance spectroscopy as a noninvasive technique to evaluate the therapeutic effects of the newly developed Pantazine BBP-671. Results 1H MRS reliably quantified changes in cerebral metabolites, including glutamate/glutamine, lactate, and N-acetyl aspartate in a neuronal Pank1 and Pank2 double-knockout (SynCre + Pank1,2 dKO) mouse model of brain CoA deficiency. The neuronal SynCre + Pank1,2 dKO mice had distinct decreases in Glx/tCr, NAA/tCr, and lactate/tCr ratios compared to the wildtype matched control mice that increased in response to BBP-671 treatment. Conclusions BBP-671 treatment completely restored glutamate/glutamine levels in the brains of the mouse model, suggesting that these metabolites are promising clinically translatable biomarkers for future therapeutic trials.

Aim. To analyze current data of scientific literature on the etiology, pathogenesis, approaches to the diagnosis and treatment of rare orphan disease – pantothenate kinase-associated neurodegeneration and to describe the clinical case of this disease. Pantothenate kinase-associated neurodegeneration (PKAN) is a rare inherited autosomal recessive disorder caused by mutations in the PANK2 gene, which is located at the chromosomal locus: 20p13-p12.3. The article presents a literature review and a case report of the diagnosis and treatment of 8-year-old girl with pantothenate kinase-associated neurodegeneration who suffered from progressive motor impairment. Among the dominant clinical manifestations is a growing extrapyramidal motor disorder, the so-called “dystonic storm”, which can range from severe sensorimotor motor deficits in infants and young children to mild parkinsonism in adults. MRI signs in the form of specific changes in the T2-weighted mode, which detects typical areas of hyperintensive signal in globus pallidus, surrounded by a border of hypointensive signal (“tiger’s eye”) are particular important. Neuroimaging data most likely make possible to suspect a correct diagnosis, reducing the time and cost of additional examinations. There is no pathogenetic treatment of this disease now. The main directions of currently available symptomatic drug therapy are described. Clinical trials of detoxifying drugs that reduce iron levels in the body (chelation) and surgical treatments are currently underway. Conclusions. The presented clinical observation once again confirms the complexity of the diagnostic search for orphan diseases of the nervous system. A key place in the diagnosis of pantothenate kinase-associated neurodegeneration belongs to the neuroimaging methods and molecular genetic testing data.

Background: Neurodegeneration with brain iron accumulation (NBIA) is a group of rare neurogenetic disorders frequently associated with iron accumulation in the basal nuclei of the brain characterized by progressive spasticity, dystonia, muscle rigidity, neuropsychiatric symptoms, and retinal degeneration or optic nerve atrophy. Pantothenate kinase-associated neurodegeneration (PKAN) is one of the most widespread NBIA subtypes. It is caused by mutations in the gene of pantothenate kinase 2 (PANK2) that result in dysfunction in PANK2 enzyme activity, with consequent deficiency of coenzyme A (CoA) biosynthesis, as well as low levels of essential metabolic intermediates such as 4'-phosphopantetheine, a necessary cofactor for essential cytosolic and mitochondrial proteins.Methods: In this manuscript, we examined the therapeutic effectiveness of pantothenate, panthetine, antioxidants (vitamin E and omega 3) and mitochondrial function boosting supplements (L-carnitine and thiamine) in mutant PANK2 cells with residual expression levels.Results: Commercial supplements, pantothenate, pantethine, vitamin E, omega 3, carnitine and thiamine were able to eliminate iron accumulation, increase PANK2, mtACP, and NFS1 expression levels and improve pathological alterations in mutant cells with residual PANK2 expression levels.Conclusion: Our results suggest that several commercial compounds are indeed able to significantly correct the mutant phenotype in cellular models of PKAN. These compounds alone or in combinations are of common use in clinical practice and may be useful for the treatment of PKAN patients with residual enzyme expression levels. [ABSTRACT FROM AUTHOR]

Abstract Background Neurodegeneration with brain iron accumulation (NBIA) is a group of genetic neurological disorders frequently associated with iron accumulation in the basal nuclei of the brain characterized by progressive spasticity, dystonia, muscle rigidity, neuropsychiatric symptoms, and retinal degeneration or optic nerve atrophy. Pantothenate kinase-associated neurodegeneration (PKAN) is the most widespread NBIA disorder. It is caused by mutations in the gene of pantothenate kinase 2 (PANK2) which catalyzes the first reaction of coenzyme A (CoA) biosynthesis. Thus, altered PANK2 activity is expected to induce CoA deficiency as well as low levels of essential metabolic intermediates such as 4′-phosphopantetheine which is a necessary cofactor for critical proteins involved in cytosolic and mitochondrial pathways such as fatty acid biosynthesis, mitochondrial respiratory complex I assembly and lysine and tetrahydrofolate metabolism, among other metabolic processes. Methods In this manuscript, we examined the effect of PANK2 mutations on the expression levels of proteins with phosphopantetheine cofactors in fibroblast derived from PKAN patients. These proteins include cytosolic acyl carrier protein (ACP), which is integrated within the multifunctional polypeptide chain of the fatty acid synthase involved in cytosolic fatty acid biosynthesis type I (FASI); mitochondrial ACP (mtACP) associated with mitocondrial fatty acid biosynthesis type II (FASII); mitochondrial alpha-aminoadipic semialdehyde synthase (AASS); and 10-formyltetrahydrofolate dehydrogenases (cytosolic, ALD1L1, and mitochondrial, ALD1L2). Results In PKAN fibroblasts the expression levels of cytosolic FAS and ALD1L1 were not affected while the expression levels of mtACP, AASS and ALD1L2 were markedly reduced, suggesting that 4′-phosphopantetheinylation of mitochondrial but no cytosolic proteins were markedly affected in PKAN patients. Furthermore, the correction of PANK2 expression levels by treatment with pantothenate in selected mutations with residual enzyme content was able to correct the expression levels of mitochondrial phosphopantetheinyl-proteins and restore the affected pathways. The positive effects of pantothenate in particular mutations were also corroborated in induced neurons obtained by direct reprograming of mutant PANK2 fibroblasts. Conclusions Our results suggest that the expression levels of mitochondrial phosphopantetheinyl-proteins are severely reduced in PKAN cells and that in selected mutations pantothenate increases the expression levels of both PANK2 and mitochondrial phosphopantetheinyl-proteins associated with remarkable improvement of cell pathophysiology.

Objective To determine the volume changes in gray and white matter during a long-term follow-up in patients suffering from pantothenate kinase-associated neurodegeneration (PKAN). Methods Magnetic resonance imaging was repeated in 13 patients and 14 age-matched controls after a mean interval of more than 7 years. T1-weighted sequences were evaluated by fully automated atlas-based volumetry, compared between groups and correlated with disease progression. Results The patients did not show generalized cerebral atrophy but did show a significantly faster volume reduction in the globus pallidus during follow-up (between -0.96% and -1.02% per year, p < 0.05 adjusted for false discovery rate) than controls, which was significantly related to the progression in their dystonia scores (p = 0.032). Conclusion The volume loss in the globus pallidus over time—together with the accumulation of iron known as the “tiger’s eye”—supports the pathophysiologic concept of this nucleus as a center of inhibition and its severe malfunction in PKAN.

Background: To examine structural connectivity of white matter tracts in patients with Pantothenate Kinase-Associated Neurodegeneration (PKAN) dystonia and identify those ones which correlate negatively to severity of symptoms.Methods: In a group of 41 patients suffering from PKAN dystonia and an age- and gender-matched control group, white matter tractography was carried out, based on diffusion tensor imaging magnetic resonance data. Postprocessing included assessment of Quantitative Anisotropy (QA) using q-space diffeomorphic reconstruction in order to reduce influence of iron accumulation in globus pallidus of patients.Results: Whole brain tractography presented significantly reduced QA values in patients (0.282 ± 0.056, as compared to controls (0.325 ± 0.046, p < 0.001). 9 fiber clusters of tracts correlated negatively to the dystonia score of patients: the middle cerebellar peduncle and the tracts of both cerebellar hemispheres as well as corpus callosum, forceps minor, the superior cortico-striate tracts and the superior thalamic radiations of both cerebral hemispheres (False Discovery Rate FDR = 0.041).Conclusion: The finding of a reduced global structural connectivity within the white matter and of negative correlation of motor system-related tracts, mainly those between the basal ganglia, cortical areas and the cerebellum, fits well to the concept of a general functional disturbance of the motor system in PKAN. [ABSTRACT FROM AUTHOR]

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Background: Pantothenate kinase (PANK) is the first and rate-controlling enzymatic step in the only pathway for cellular coenzyme A (CoA) biosynthesis. PANK-associated neurodegeneration (PKAN), formerly known as Hallervorden-Spatz disease, is a rare, life-threatening neurologic disorder that affects the CNS and arises from mutations in the human PANK2 gene. Pantazines, a class of small molecules containing the pantazine moiety, yield promising therapeutic effects in an animal model of brain CoA deficiency. A reliable technique to identify the neurometabolic effects of PANK dysfunction and to monitor therapeutic responses is needed.Methods: We applied 1H magnetic resonance spectroscopy as a noninvasive technique to evaluate the therapeutic effects of the newly developed Pantazine BBP-671.Results: 1H MRS reliably quantified changes in cerebral metabolites, including glutamate/glutamine, lactate, and N-acetyl aspartate in a neuronal Pank1 and Pank2 double-knockout (SynCre+ Pank1,2 dKO) mouse model of brain CoA deficiency. The neuronal SynCre+ Pank1,2 dKO mice had distinct decreases in Glx/tCr, NAA/tCr, and lactate/tCr ratios compared to the wildtype matched control mice that increased in response to BBP-671 treatment.Conclusions: BBP-671 treatment completely restored glutamate/glutamine levels in the brains of the mouse model, suggesting that these metabolites are promising clinically translatable biomarkers for future therapeutic trials. [ABSTRACT FROM AUTHOR]

Pantothenate kinase-associated neurodegeneration (PKAN) is a rare autosomal-recessive and neurodegenerative disorder associated with progressive motor impairment and mental deterioration. The diagnosis of PKAN consists of clinical features and magnetic resonance imaging (MRI) evidence of iron accumulation in the brain, as well as evidence of mutations in the pantothenate kinase 2 (PANK2) gene. Typical clinical features of PKAN are motor symptoms including dystonia, involuntary movement, rigidity and dysarthria, as well as psychiatric symptoms such as anxiety, depression, and mental retardation. However, psychosis has not been reported often in cases of PKAN. This patient presented with anxiety, a tendency to startle easily, and rapidly deteriorating memory impairment. T2-weighted MRI of his brain indicated a specific pattern of hyperintensity within a hypointense medial globus pallidus with a mutation in the gene encoding PANK2. Components of the basal ganglia, including the globus pallidus, play a key role in motor symptoms, cognition, affect, and mood. The basal ganglia are also a central factor in the pathogenesis of psychiatric symptoms in schizophrenia. These lesions are able to aggravate various psychotic symptoms, cognitive function impairments, and mood disorders because PKAN is affected by abnormal iron deposition in the globus pallidus and substantia nigra pars reticulata.

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.

Pantothenate kinase-associated neurodegeneration (or previously known as Hallervorden-Spatz syndrome) is a very rare disorder that typically manifests in a child with neurological signs such as gait difficulties, dysarthria, and hyperreflexia, associated potentially with psychiatric symptoms such as cognitive decline. It demonstrates on MRI the typical 'eye of the tiger' appearance, which is due to gliosis and accumulation of iron in the globi pallidi. Other differentials can mimic this appearance on MRI, it is therefore important to search for the involvement of other basal ganglia nuclei and the cerebral cortex, and also to consider the clinical and biological context. [ABSTRACT FROM AUTHOR]

Despite certain overlapping clinical presentations, the two human neurodegenerative diseases pantothenate kinase-associated neurodegeneration (PKAN) and Parkinson disease (PD) have distinct genetic etiologies. During our work using Drosophila to study PKAN and PINK1-related PD, we found some common mitochondrial abnormalities in these two disease models, suggesting a potential link in pathogenesis between them. When we delve into their underlying mechanisms, mitochondrial quality control (MQC) stands at the crossroads. While overwhelming evidence suggests that mitochondrial dysfunction plays a role in the pathogenesis of many human neurodegenerative diseases, mitochondrial function is particularly important for PKAN and PD (some inherited PD cases) foretold by the nature of their causative genes. PKAN is caused by mutations in PANK2 (pantothenate kinase 2), the only PANK localized to mitochondria among the four human PANK isoforms. PANKs catalyze the initial step of de novo coenzyme A (CoA) synthesis. PKAN patients and disease models display disturbed mitochondrial functions, but its exact mechanism has not been clearly determined. Usually, damaged mitochondria are surveyed and eliminated by the MQC pathway. Two genes that have been found critical for PD, PINK1 (PTEN induced kinase 1) and PRKN (parkin RBR E3 ubiquitin protein ligase), are positioned at the center of MQC. If the MQC is normal, malfunctional mitochondria will usually be efficiently repaired. Thus, the accumulation of mitochondrial dysfunction in PKAN implies that its MQC mechanism is impaired. The question is, how? In a recent published work, we attempted to answer this question. [ABSTRACT FROM AUTHOR]

Background: This review highlights the recent scientific advances that have enabled rational design of novel clinical trials for pantothenate kinase‐associated neurodegeneration (PKAN), a rare autosomal recessive neurogenetic disorder associated with progressive neurodegenerative changes and functional impairment. PKAN is caused by genetic variants in the PANK2 gene that result in dysfunction in pantothenate kinase 2 (PANK2) enzyme activity, with consequent disruption of coenzyme A (CoA) synthesis, and subsequent accumulation of brain iron. The clinical phenotype is varied and may include dystonia, rigidity, bradykinesia, postural instability, spasticity, loss of ambulation and ability to communicate, feeding difficulties, psychiatric issues, and cognitive and visual impairment. There are several symptom‐targeted treatments, but these do not provide sustained benefit as the disorder progresses. Objectives: A detailed understanding of the molecular and biochemical pathogenesis of PKAN has opened the door for the design of novel rationally designed therapeutics that target the underlying mechanisms. Methods: Two large double‐blind phase 3 clinical trials have been completed for deferiprone (an iron chelation treatment) and fosmetpantotenate (precursor replacement therapy). A pilot open‐label trial of pantethine as a potential precursor replacement strategy has also been completed, and a trial of 4‐phosphopantetheine has begun enrollment. Several other compounds have been evaluated in pre‐clinical studies, and additional clinical trials may be anticipated. Conclusions: Experience with these trials has encouraged a critical evaluation of optimal trial designs, as well as the development of PKAN‐specific measures to monitor outcomes. PKAN provides a valuable example for understanding targeted drug development and clinical trial design for rare disorders. © 2021 International Parkinson and Movement Disorder Society [ABSTRACT FROM AUTHOR]

Pantothenate kinase-associated neurodegeneration (PKAN) is a rare hereditary neurodegenerative disease characterized by an accumulation of iron within the brain. In the present report, we describe a family with 4 affected siblings presenting with variable clinical manifestations, e.g., parkinsonian features, dystonia and slow disease progression over 5 years. Exome sequencing revealed a causative variant in the pantothenate kinase 2 gene (PANK2). Variant NM_024960.6:c.710C > T was homozygous in all affected subjects. Our report describes the first genetically confirmed cases of PKAN in the Egyptian population. Studying genetics of neurodegenerative diseases in different ethnicities is very important for determining clinical phenotypes and understanding pathomechanisms of these diseases.

Background: Pantothenate kinase-associated neurodegeneration (PKAN) is a rare neurologic disorder included in the group of neurodegeneration with brain iron accumulation diseases (NBIA). Information regarding sleep in patients with PKAN is limited.Objectives: To describe the clinical and polysomnographic characteristics of sleep in six patients with genetically confirmed PKAN.Methods: The evaluation included a clinical interview, sleep questionnaires -Epworth Sleepiness Scale (ESS), Pittsburgh Sleep Quality Index (PSQI) and Hospital Anxiety and Depression Scale (HADS)- and a video-polysomnography (VPSG). In addition to standard sleep measures we manually quantified sleep spindle density in stage N2 and rapid eye movements in REM sleep comparing the results with matched controls. Quantification of EMG activity in REM sleep was performed following standard criteria.Results: All the patients reported at least one sleep complaint, most commonly sleep fragmentation (4/6) and sleep onset insomnia (3/6). ESS and PSQI were abnormal in 3/6 and 4/6, respectively. VPSG showed in 4/6 decreased ocular movements during REM sleep, an increase in sleep spindles in 3/6 (all of them with deep brain pallidal stimulation), an absence of slow wave sleep in 2 and undifferentiated NREM sleep and delayed sleep phase in one. Three patients had an abnormal sleep apnea/hypopnea index, and 2 periodic limb movements of sleep. REM sleep muscular atonia was preserved in all.Conclusions: Sleep disorders are common in patients with PKAN. Although our sample is small and heterogeneous, with different symptomatic treatments possibly influencing the results, it suggests that evaluation of sleep should be considered in their management. [ABSTRACT FROM AUTHOR]

Pantothenate kinase-associated neurodegeneration is an inherited neurodegenerative disease consisting of brain iron accumulation in basal ganglia. Extrapyramidal symptoms are common. Gait and posture disorders are also observed, but characteristics of these disorders have not been identified in the literature. We shared our experiences about gait disorders in a patient with pantothenate kinase-associated neu rodegeneration and the effectiveness of rehabilitation by using three-dimensional gait analysis. A better posture and walking stability are observed in this patient as a consequence of rehabilitation. Three-dimensional gait analysis is an objective tool to obtain quantitative gait data which helps to determine main requirements to improve the patient's gait and posture before planning rehabilitation. [ABSTRACT FROM AUTHOR]

Background: Pantothenate kinase–associated neurodegeneration (PKAN) currently has no approved treatments. Objectives: The Fosmetpantotenate Replacement Therapy pivotal trial examined whether treatment with fosmetpantotenate improves PKAN symptoms and stabilizes disease progression. Methods: This randomized, double‐blind, placebo‐controlled, multicenter study evaluated fosmetpantotenate, 300 mg oral dose three times daily, versus placebo over a 24‐week double‐blind period. Patients with pathogenic variants of PANK2, aged 6 to 65 years, with a score ≥6 on the PKAN‐Activities of Daily Living (PKAN‐ADL) scale were enrolled. Patients were randomized to active (fosmetpantotenate) or placebo treatment, stratified by weight and age. The primary efficacy endpoint was change from baseline at week 24 in PKAN‐ADL. Results: Between July 23, 2017, and December 18, 2018, 84 patients were randomized (fosmetpantotenate: n = 41; placebo: n = 43); all 84 patients were included in the analyses. Six patients in the placebo group discontinued treatment; two had worsening dystonia, two had poor compliance, and two died of PKAN‐related complications (aspiration during feeding and disease progression with respiratory failure, respectively). Fosmetpantotenate and placebo group PKAN‐ADL mean (standard deviation) scores were 28.2 (11.4) and 27.4 (11.5) at baseline, respectively, and were 26.9 (12.5) and 24.5 (11.8) at week 24, respectively. The difference in least square mean (95% confidence interval) at week 24 between fosmetpantotenate and placebo was −0.09 (−1.69 to 1.51; P = 0.9115). The overall incidence of treatment‐emergent serious adverse events was similar in the fosmetpantotenate (8/41; 19.5%) and placebo (6/43; 14.0%) groups. Conclusions: Treatment with fosmetpantotenate was safe but did not improve function assessed by the PKAN‐ADL in patients with PKAN. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Neurodegeneration with brain iron accumulation is a broad term that describes a heterogeneous group of progressive and invalidating neurologic disorders in which iron deposits in certain brain areas, mainly the basal ganglia. The predominant clinical symptoms include spasticity, progressive dystonia, Parkinson’s disease-like symptoms, neuropsychiatric alterations, and retinal degeneration. Among the neurodegeneration with brain iron accumulation disorders, the most frequent subtype is pantothenate kinase-associated neurodegeneration (PKAN) caused by defects in the gene encoding the enzyme pantothenate kinase 2 (PANK2) which catalyzed the first reaction of the coenzyme A biosynthesis pathway. Currently there is no effective treatment to prevent the inexorable course of these disorders. The aim of this review is to open up a discussion on the utility of using cellular models derived from patients as a valuable tool for the development of precision medicine in PKAN. Recently, we have described that dermal fibroblasts obtained from PKAN patients can manifest the main pathological changes of the disease such as intracellular iron accumulation accompanied by large amounts of lipofuscin granules, mitochondrial dysfunction and a pronounced increase of markers of oxidative stress. In addition, PKAN fibroblasts showed a morphological senescence-like phenotype. Interestingly, pantothenate supplementation, the substrate of the PANK2 enzyme, corrected all pathophysiological alterations in responder PKAN fibroblasts with low/residual PANK2 enzyme expression. However, pantothenate treatment had no favourable effect on PKAN fibroblasts harbouring mutations associated with the expression of a truncated/incomplete protein. The correction of pathological alterations by pantothenate in individual mutations was also verified in induced neurons obtained by direct reprograming of PKAN fibroblasts. Our observations indicate that pantothenate supplementation can increase/stabilize the expression levels of PANK2 in specific mutations. Fibroblasts and induced neurons derived from patients can provide a useful tool for recognizing PKAN patients who can respond to pantothenate treatment. The presence of low but significant PANK2 expression which can be increased in particular mutations gives valuable information which can support the treatment with high dose of pantothenate. The evaluation of personalized treatments in vitro of fibroblasts and neuronal cells derived from PKAN patients with a wide range of pharmacological options currently available, and monitoring its effect on the pathophysiological changes, can help for a better therapeutic strategy. In addition, these cell models will be also useful for testing the efficacy of new therapeutic options developed in the future.

Neurodegeneration with Brain Iron Accumulation (NBIA) is a heterogeneous group of progressive neurodegenerative diseases characterized by iron deposition in the globus pallidus and the substantia nigra. As of today, 15 distinct monogenetic disease entities have been identified. The four most common forms are pantothenate kinase-associated neurodegeneration (PKAN), phospholipase A2 group VI (PLA2G6)-associated neurodegeneration (PLAN), beta-propeller protein-associated neurodegeneration (BPAN) and mitochondrial membrane protein-associated neurodegeneration (MPAN). Neurodegeneration with Brain Iron Accumulation disorders present with a wide spectrum of clinical symptoms such as movement disorder signs (dystonia, parkinsonism, chorea), pyramidal involvement (e.g., spasticity), speech disorders, cognitive decline, psychomotor retardation, and ocular abnormalities. Treatment remains largely symptomatic but new drugs are in the pipeline. In this review, we discuss the rationale of new compounds, summarize results from clinical trials, provide an overview of important results in cell lines and animal models and discuss the future development of disease-modifying therapies for NBIA disorders. A general mechanistic approach for treatment of NBIA disorders is with iron chelators which bind and remove iron. Few studies investigated the effect of deferiprone in PKAN, including a recent placebo-controlled double-blind multicenter trial, demonstrating radiological improvement with reduction of iron load in the basal ganglia and a trend to slowing of disease progression. Disease-modifying strategies address the specific metabolic pathways of the affected enzyme. Such tailor-made approaches include provision of an alternative substrate (e.g., fosmetpantotenate or 4′-phosphopantetheine for PKAN) in order to bypass the defective enzyme. A recent randomized controlled trial of fosmetpantotenate, however, did not show any significant benefit of the drug as compared to placebo, leading to early termination of the trials' extension phase. 4′-phosphopantetheine showed promising results in animal models and a clinical study in patients is currently underway. Another approach is the activation of other enzyme isoforms using small molecules (e.g., PZ-2891 in PKAN). There are also compounds which counteract downstream cellular effects. For example, deuterated polyunsaturated fatty acids (D-PUFA) may reduce mitochondrial lipid peroxidation in PLAN. In infantile neuroaxonal dystrophy (a subtype of PLAN), desipramine may be repurposed as it blocks ceramide accumulation. Gene replacement therapy is still in a preclinical stage.

Background: Neurodegeneration with brain iron accumulation (NBIA) is a group of genetic neurological disorders frequently associated with iron accumulation in the basal nuclei of the brain characterized by progressive spasticity, dystonia, muscle rigidity, neuropsychiatric symptoms, and retinal degeneration or optic nerve atrophy. Pantothenate kinase-associated neurodegeneration (PKAN) is the most widespread NBIA disorder. It is caused by mutations in the gene of pantothenate kinase 2 (PANK2) which catalyzes the first reaction of coenzyme A (CoA) biosynthesis. Thus, altered PANK2 activity is expected to induce CoA deficiency as well as low levels of essential metabolic intermediates such as 4'-phosphopantetheine which is a necessary cofactor for critical proteins involved in cytosolic and mitochondrial pathways such as fatty acid biosynthesis, mitochondrial respiratory complex I assembly and lysine and tetrahydrofolate metabolism, among other metabolic processes.Methods: In this manuscript, we examined the effect of PANK2 mutations on the expression levels of proteins with phosphopantetheine cofactors in fibroblast derived from PKAN patients. These proteins include cytosolic acyl carrier protein (ACP), which is integrated within the multifunctional polypeptide chain of the fatty acid synthase involved in cytosolic fatty acid biosynthesis type I (FASI); mitochondrial ACP (mtACP) associated with mitocondrial fatty acid biosynthesis type II (FASII); mitochondrial alpha-aminoadipic semialdehyde synthase (AASS); and 10-formyltetrahydrofolate dehydrogenases (cytosolic, ALD1L1, and mitochondrial, ALD1L2).Results: In PKAN fibroblasts the expression levels of cytosolic FAS and ALD1L1 were not affected while the expression levels of mtACP, AASS and ALD1L2 were markedly reduced, suggesting that 4'-phosphopantetheinylation of mitochondrial but no cytosolic proteins were markedly affected in PKAN patients. Furthermore, the correction of PANK2 expression levels by treatment with pantothenate in selected mutations with residual enzyme content was able to correct the expression levels of mitochondrial phosphopantetheinyl-proteins and restore the affected pathways. The positive effects of pantothenate in particular mutations were also corroborated in induced neurons obtained by direct reprograming of mutant PANK2 fibroblasts.Conclusions: Our results suggest that the expression levels of mitochondrial phosphopantetheinyl-proteins are severely reduced in PKAN cells and that in selected mutations pantothenate increases the expression levels of both PANK2 and mitochondrial phosphopantetheinyl-proteins associated with remarkable improvement of cell pathophysiology. [ABSTRACT FROM AUTHOR]

Neurodegeneration with Brain Iron Accumulation (NBIA) is a heterogeneous group of progressive neurodegenerative diseases characterized by iron deposition in the globus pallidus and the substantia nigra. As of today, 15 distinct monogenetic disease entities have been identified. The four most common forms are pantothenate kinase-associated neurodegeneration (PKAN), phospholipase A2 group VI (PLA2G6)-associated neurodegeneration (PLAN), beta-propeller protein-associated neurodegeneration (BPAN) and mitochondrial membrane protein-associated neurodegeneration (MPAN). Neurodegeneration with Brain Iron Accumulation disorders present with a wide spectrum of clinical symptoms such as movement disorder signs (dystonia, parkinsonism, chorea), pyramidal involvement (e.g., spasticity), speech disorders, cognitive decline, psychomotor retardation, and ocular abnormalities. Treatment remains largely symptomatic but new drugs are in the pipeline. In this review, we discuss the rationale of new compounds, summarize results from clinical trials, provide an overview of important results in cell lines and animal models and discuss the future development of disease-modifying therapies for NBIA disorders. A general mechanistic approach for treatment of NBIA disorders is with iron chelators which bind and remove iron. Few studies investigated the effect of deferiprone in PKAN, including a recent placebo-controlled double-blind multicenter trial, demonstrating radiological improvement with reduction of iron load in the basal ganglia and a trend to slowing of disease progression. Disease-modifying strategies address the specific metabolic pathways of the affected enzyme. Such tailor-made approaches include provision of an alternative substrate (e.g., fosmetpantotenate or 4′-phosphopantetheine for PKAN) in order to bypass the defective enzyme. A recent randomized controlled trial of fosmetpantotenate, however, did not show any significant benefit of the drug as compared to placebo, leading to early termination of the trials' extension phase. 4′-phosphopantetheine showed promising results in animal models and a clinical study in patients is currently underway. Another approach is the activation of other enzyme isoforms using small molecules (e.g., PZ-2891 in PKAN). There are also compounds which counteract downstream cellular effects. For example, deuterated polyunsaturated fatty acids (D-PUFA) may reduce mitochondrial lipid peroxidation in PLAN. In infantile neuroaxonal dystrophy (a subtype of PLAN), desipramine may be repurposed as it blocks ceramide accumulation. Gene replacement therapy is still in a preclinical stage. [ABSTRACT FROM AUTHOR]

Background and purpose: The aim of this study was to look for deviations of cerebral perfusion in patients suffering from pantothenate kinase-associated neurodegeneration, where the globus pallidus is affected by severe accumulation of iron. Material and methods: Under resting conditions, cerebral blood flow was measured by the magnetic resonance imaging technique of arterial spin labelling in cortical areas and basal ganglia in eight pantothenate kinase-associated neurodegeneration patients and 14 healthy age-matched control subjects and correlated to T2* time of these areas and – in patients – to clinical parameters. Results: Despite highly significant differences of T2* time of the globus pallidus (20 vs 39 ms, p < 0.001), perfusion values of this nucleus were nearly identical in both groups (32 ± 3.3 vs 31 ± 4.0 ml/min/100 g) as well as in total brain gray matter (both 62 ± 6.7 resp. ±10.3 ml/min/100 g), putamen (41 ± 5.4 vs 40 ± 6.1 ml/min/100 g), in selected cortical regions, and the cerebellum. Correlations between perfusion and T2* time to clinical data did not reach significance (p > 0.05). Conclusion: The absence of any obvious deviations of perfusion in the group of patients during a resting condition does not support the view that (non-functional) vascular pathology is a major pathogenic factor in pantothenate kinase-associated neurodegeneration in the younger age group. The findings underline the value of the arterial spin technique to measure cerebral blood flow in areas of disturbed susceptibility. [ABSTRACT FROM AUTHOR]

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).

Pantothenate kinase-associated neurodegeneration (PKAN) is a progressive neurodegenerative disease caused by mutations in the pantothenate kinase 2 (PANK2) gene and associated with iron deposition in basal ganglia. Pantothenate kinase isoforms catalyze the first step in coenzyme A (CoA) biosynthesis. Since PANK2 is the only isoform in erythrocytes, these cells are an excellent ex vivo model to study the effect of PANK2 point mutations on expression/stability and activity of the protein as well as on the downstream molecular consequences. PKAN erythrocytes containing the T528M PANK2 mutant had residual enzyme activities but variable PANK2 abundances indicating an impaired regulation of the protein. Patients with G521R/G521R, G521R/G262R, and R264N/L275fs PANK2 mutants had no residual enzyme activity and strongly reduced PANK2 abundance. G521R inactivates the catalytic activity of the enzyme, whereas G262R and the R264N point mutations impair the switch from the inactive to the active conformation of the PANK2 dimer. Metabolites in cytosolic extracts were analyzed by gas chromatography–mass spectrometry and multivariate analytic methods revealing changes in the carboxylate metabolism of erythrocytes from PKAN patients as compared to that of the carrier and healthy control. Assuming low/absent CoA levels in PKAN erythrocytes, changes are consistent with a model of altered citrate channeling where citrate is preferentially converted to α-ketoglutarate and α-hydroxyglutarate instead of being used for de novo acetyl-CoA generation. This finding hints at the importance of carboxylate metabolism in PKAN pathology with potential links to reduced cytoplasmic acetyl-CoA levels in neurons and to aberrant brain iron regulation.

Introduction: Pantothenate kinase-associated neurodegeneration (PKAN) is a rare autosomal recessive disorder with a progressive clinical course. In addition to symptomatic therapy, DBS has been increasingly recognized as a potential therapeutic strategy, especially in severe cases. Therefore, we wanted to report our experience regarding benefits of DBS in five PKAN cases in 3-year follow-up study. Methods: Five genetically confirmed PKAN patients from Serbia underwent GPi-DBS. To assess clinical outcome, we reviewed medical charts and applied: Schwab and England Activities of Daily Living Scale (S&E), EQ-5D questionnaire for quality of life, Patient Global Impression of Improvement (GPI-I), Functional Independence Measure (FIM), Burke–Fahn–Marsden Dystonia Rating Scale (BFMDRS), Barry Albright Dystonia Scale (BAD). Patients were evaluated in five visits: at the disease onset, 5 years after the onset, before surgery, 6 months and 14–36 months after the surgery. Improvement of 20% was accepted as significant. Results: Overall, dystonia significantly improved after GPi-DBS at 6 and 14–36 months postoperatively, when assessed by the BFMDRS and BAD. However, two patients failed to improve considerably. Four patients reported improvement on GPI-I, while one remained unchanged. Three patients reported significant improvement, when assessed with S&E and FIM. EQ-5D showed the most prominent improvement in the domains of mobility and pain/discomfort. Conclusion: Three out of our five patients experienced beneficial effects of the GPi-DBS, in up to 36 months follow-up. Two patients who had not reached significant improvement had longer disease duration; therefore, it might be reasonable to recommend GPi-DBS as soon as dystonia became disabling. [ABSTRACT FROM AUTHOR]