Clinical, imaging and genetic profile of twenty-four patients with pantothenate kinase-associated neurodegeneration (PKAN)- A single centre study from India.

INTRODUCTION: Pantothenate kinase-associated neurodegeneration (PKAN) is the most common "Neurodegeneration with Brain Iron Accumulation" disorder. This study aimed to study the clinical, radiological and genetic profiling of a large cohort of patients with PKAN. METHODS: This is an ambispective hospital-based single centre study conducted at a tertiary care centre from India. After tabulating the clinical details, appropriate rating scales were applied followed by magnetic resonance imaging brain and exome sequencing. The segregation of the causal variants in the families were analysed using Sanger sequencing. RESULTS: Twenty-four patients (14 males) with a median age at initial examination of 13 years (range: 4-54 years) and age at onset of 8 years (range: 0.5-40 years) were identified. Almost two-thirds (62%) had onset before 10 years. Difficulty walking was the most common presenting symptom (41.6%) and dystonia was the most common extrapyramidal phenomenology (100%) followed by parkinsonism (54.2%). Retinitis pigmentosa was present in 37.5% patients. MRI showed hypo intensity on T2 and SWI sequences in globus pallidus (100%), substantia nigra (70.8%) and red nucleus (12.5%). Eye-of-the-tiger sign was present in 95.8%. Biallelic variants in PANK2 gene was identified in all 20 patients who underwent genetic testing. Among the 18 unique variants identified in these 20 patients 10 were novel. Sanger sequencing confirmed the segregation of the mutation in the available family members. CONCLUSIONS: Wide range of age at onset was noted. Dystonia at presentation, pathognomonic eye-of-tiger sign, and disease-causing variants in PANK2 gene were identified in nearly all patients. Ten novel variants were identified expanding the genotypic spectrum of PKAN.

Cerebral and cerebellar white matter tract alterations in patients with Pantothenate Kinase-Associated Neurodegeneration (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.

Cerebral blood flow in dystonia due to pantothenate kinase-associated neurodegeneration.

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.

Neuropsychological functions and psychiatric symptoms in late-onset manifestation of pantothenate kinase-associated neurodegeneration: a clinical case report.

Purpose of the study: Pantothenate Kinase-associated Neurodegeneration (PKAN) is a form of Neurodegeneration with brain iron accumulation (NBIA) due to gene mutations. Classical phenotype showed progressive neurological symptoms associated to a characteristic pattern of basal ganglia iron deposits. The atypical case, with adult-onset manifestation, could have neuropsychiatric symptoms with behavioral deficits. We described an adult-onset case of Pantothenate Kinase-associated Neurodegeneration.Materials and methods: The patient underwent neuropsychological and psychiatric evaluation and Magnetic Resonance Imaging, respectively for cognitive and behavioral assessment and to confirm the characteristic findings of this syndrome.Results: The patient showed atypical phenotype of Pantothenate Kinase-associated Neurodegeneration, characterized by language deficits, dixesecutive, and psychiatric manifestations, such as obsessive ideation, impulsivity, and disinhibition.Conclusions: This description could be helpful to a more correct diagnosis and clinical management.

Diagnostic and clinical experience of patients with pantothenate kinase-associated neurodegeneration.

BACKGROUND: Pantothenate kinase-associated neurodegeneration (PKAN) is an autosomal recessive neurodegenerative disorder with brain iron accumulation (NBIA). OBJECTIVES: To assess PKAN diagnostic pathway, history, and burden across the spectrum of PKAN severity from patient and/or caregiver perspectives. METHODS: Caregivers of patients (n = 37) and patients themselves (n = 2) were interviewed in a validation study of the PKAN-Activities of Daily Living (ADL) scale. The current study used quartiles of the PKAN-ADL total score to divide patients by severity of impairment (Lowest, Second Lowest, Third Lowest, Highest). Diagnostic and treatment history, healthcare utilization, disease burden, and caregiver experience were compared between groups. RESULTS: The analyses included data from 39 patients. Mean age at PKAN symptom onset (P = 0.0007), initial MRI (P = 0.0150), and genetic testing (P = 0.0016) generally decreased across the PKAN severity spectrum. The mean duration of illness did not differ among PKAN severity groups (range, 9.7-15.2 years; P = 0.3029). First MRI led to diagnosis in 56.4% of patients (range, 30.0-90.0%). A mean (SD) of 13.0 (13.1) medical and 55.2 (78.5) therapy visits (eg, physical, speech) occurred in the past year. More patients in the higher PKAN severity groups experienced multiple current functional losses and/or earlier onset of problems (P-values < 0.0500). Over half (56.8%) of caregivers experienced a change in employment because of caregiving. The percentage of patients requiring full-time caregiving increased across the PKAN severity spectrum (range, 11.1-100%; P = 0.0021). CONCLUSIONS: PKAN diagnosis was often delayed, most probably due to low awareness. Considerable burden of functional impairment and high healthcare utilization were found across the PKAN severity spectrum.

Novel PANK2 mutation discovered among South East Asian children living in Thailand affected with pantothenate kinase associated neurodegeneration.

Pantothenate kinase-associated neurodegeneration (PKAN) is linked to brain iron accumulation caused by PANK2 gene mutation. Despite the importance of genetic testing to confirm PKAN and identify at risk parents, genetic screening is financially burdensome for developing countries like Thailand. Because genetic screeners are expensive and not reimbursed by the universal health care coverage system, they are not typically performed. To investigate clinical symptoms, radiological findings and mutation analysis for patients based in Thailand with unknown genetic status but suspected PKAN based on clinical symptoms. Genetic testing was performed for cases suspected for PKAN and their biological parents by direct genomic sequencing of PANK2 at Maharat Nakhon Ratchasima Hospital during 2017-2018. Clinical evaluation and documentation were performed by pediatric neurologists. Five children had classical onset form of PKAN. Most presented with gait dystonia. Three patients diagnosed after 4 years showed the eye-of-the-tiger sign in their brain MRI, whereas two younger patients revealed only isolated hyperintensity bilateral globus pallidus. However, PANK2 mutations were identified in all cases: the most common mutation was c.982-1G>C. This mutation was detected in four unrelated individuals but not reported in other studies. Genetic testing is recommended to confirm diagnoses in cases with supporting clinical features of PKAN with or without the classical 'eye-of-the-tiger-sign'. A novel PANK2 mutation (c.982-1G>C) was identified in South East Asian populations based in Thailand, suggesting that this genetic variant is a founder genotype in this population. Moreover, genetic diagnosis is helpful to provide appropriate genetic counseling to families.

Magnetic resonance imaging, susceptibility weighted imaging and quantitative susceptibility mapping findings of pantothenate kinase-associated neurodegeneration.

Pantothenate kinase-associated neurodegeneration (PKAN) is extremely rare. In this study, we aimed to evaluate the magnetic resonance imaging (MRI) findings of PKAN patients. Conventional MRI and susceptibility weighted imaging (SWI) sequences and quantitative susceptibility mapping (QSM) maps of six patients from three PKAN families and eight healthy male volunteers were retrospectively analyzed. Iron content was represented by QSM values. The typical eye-of-the-tiger sign (n = 4) and hyperintensity (n = 2) of the bilateral globus pallidus (GP) were observed on T2WI sequences. The SWI signal was low (n = 5), and the QSM values were obviously higher (n = 2), which manifested as a reversed eye-of-the-tiger sign (n = 4) and hyperintensity (n = 2) on the QSM map. The QSM values were higher in the bilateral central GP, bilateral peripheral GP, and bilateral substantia nigra (SN) and lower in the left red nucleus (RN) compared with the healthy controls. No significant differences were observed in the right RN, bilateral thalamus and bilateral occipital regions. Low signals on SWI sequences and high QSM values with a reversed eye-of-the-tiger sign on QSM maps are important for the diagnosis of PKAN, especially in patients who do not show the eye-of-the-tiger sign in early stages. The eye-of-the-tiger sign observed on T2WI is helpful in diagnosing PKAN when the disease has already progressed to an advanced stage.

"Eye of the Tiger" in a Non-Responsive Neuropsychiatric Patient: A Case Report.

Hallervorden-Spatz syndrome is a rare neurodegenerative disorder with hereditary properties. It usually occurs in young adolescents with extrapyramidal symptoms besides disturbed mental function. In this study, we present a 23-year-old neuropsychiatric patient who primarily misdiagnosed to have conversion disorder. She had 5-year history of progressive dysarthria and generalized abnormal movements. After detecting the pathognomonic sign of "eye of the tiger" diagnosis was confirmed. The patient was discharged. She had satisfactory condition in her follow-up. Such a rare syndrome should be considered in patients with similar presentation, and upon the diagnosis, PKAN2 gene study should be done to detect possible new mutations.

Looking Deep into the Eye-of-the-Tiger in Pantothenate Kinase-Associated Neurodegeneration.

BACKGROUND AND PURPOSE: A detailed delineation of the MR imaging changes in the globus pallidus in pantothenate kinase-associated neurodegeneration will be helpful for diagnosis and monitoring of patients. The aim of this study was to determine the morphologic spectrum of the "eye-of-the-tiger" sign and the topographic pattern of iron deposition in a group of patients with pantothenate kinase-associated neurodegeneration. MATERIALS AND METHODS: Seventy-four MR imaging scans from 54 individuals with PANK2 mutations were analyzed for signal patterns in the globus pallidus. Sixteen SWI data from 15 patients who underwent 1.5T (n = 7), 3T (n = 7), and 7T (n = 2) MR imaging were included to visualize the iron topography. RESULTS: The linear hyperintensity alongside the medial border of the globus pallidus was the earliest T2 signal change. This finding was evident before SWI changes from iron deposition became visible. T2WI performed in early childhood mostly showed isolated hyperintense signal. In adult patients, marked signal reduction within an earlier hyperintense center resulting from iron accumulation led to the loss of signal difference between the central and surrounding areas. Signal hypointensity on SWI progressed from the medial to the lateral portion of the globus pallidus with increasing age. The fiber connections between the medial globus pallidus and the anteromedial aspect of the substantia nigra and subthalamic nucleus were markedly hypointense on SWI. CONCLUSIONS: In pantothenate kinase-associated neurodegeneration, the globus pallidus MR imaging changes using SWI develop as region-specific and age-dependent phenomena. Signal inhomogeneity was observed across the globus pallidus in pantothenate kinase-associated neurodegeneration and should be considered when determining the concentration of iron.

On the complexity of clinical and molecular bases of neurodegeneration with brain iron accumulation.

Neurodegeneration with brain iron accumulation (NBIA) is a group of inherited heterogeneous neurodegenerative rare disorders. These patients present with dystonia, spasticity, parkinsonism and neuropsychiatric disturbances, along with brain magnetic resonance imaging (MRI) evidence of iron accumulation. In sum, they are devastating disorders and to date, there is no specific treatment. Ten NBIA genes are accepted: PANK2, PLA2G6, C19orf12, COASY, FA2H, ATP13A2, WDR45, FTL, CP, and DCAF17; and nonetheless, a relevant percentage of patients remain without genetic diagnosis, suggesting that other novel NBIA genes remain to be discovered. Overlapping complex clinical pictures render an accurate differential diagnosis difficult. Little is known about the pathophysiology of NBIAs. The reported NBIA genes take part in a variety of pathways: CoA synthesis, lipid and iron metabolism, autophagy, and membrane remodeling. The next-generation sequencing revolution has achieved relevant advances in genetics of Mendelian diseases and provide new genes for NBIAs, which are investigated according to 2 main strategies: genes involved in disorders with similar phenotype and genes that play a role in a pathway of interest. To achieve an effective therapy for NBIA patients, a better understanding of the biological process underlying disease is crucial, moving toward a new age of precision medicine.

A variation in PANK2 gene is causing Pantothenate kinase-associated Neurodegeneration in a family from Jammu and Kashmir - India.

Pantothenate kinase-associated neurodegeneration is a rare hereditary neurodegenerative disorder associated with nucleotide variation(s) in mitochondrial human Pantothenate kinase 2 (hPanK2) protein encoding PANK2 gene, and is characterized by symptoms of extra-pyramidal dysfunction and accumulation of non-heme iron predominantly in the basal ganglia of the brain. In this study, we describe a familial case of PKAN from the State of Jammu and Kashmir (J&K), India based on the clinical findings and genetic screening of two affected siblings born to consanguineous normal parents. The patients present with early-onset, progressive extrapyramidal dysfunction, and brain Magnetic Resonance imaging (MRI) suggestive of symmetrical iron deposition in the globus pallidi. Screening the PANK2 gene in the patients as well as their unaffected family members revealed a functional single nucleotide variation, perfectly segregating in the patient's family in an autosomal recessive mode of inheritance. We also provide the results of in-silico analyses, predicting the functional consequence of the identified PANK2 variant.

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

INTRODUCTION: 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. METHODS: 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). RESULTS: 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. CONCLUSION: STN stimulation could serve as a candidate DBS target in the treatment of PKAN, especially for patients with prominent appendicular symptoms.

A diagnostic approach for neurodegeneration with brain iron accumulation: clinical features, genetics and brain imaging.

Neurodegeneration with brain iron accumulation (NBIA) represents a heterogeneous and complex group of inherited neurodegenerative diseases, characterized by excessive iron accumulation, particularly in the basal ganglia. Common clinical features of NBIA include movement disorders, particularly parkinsonism and dystonia, cognitive dysfunction, pyramidal signs, and retinal abnormalities. The forms of NBIA described to date include pantothenase kinase-associated neurodegeneration (PKAN), phospholipase A2 associated neurodegeneration (PLAN), neuroferritinopathy, aceruloplasminemia, beta-propeller protein-associated neurodegeneration (BPAN), Kufor-Rakeb syndrome, mitochondrial membrane protein-associated neurodegeneration (MPAN), fatty acid hydroxylase-associated neurodegeneration (FAHN), coenzyme A synthase protein-associated neurodegeneration (CoPAN) and Woodhouse-Sakati syndrome. This review is a diagnostic approach for NBIA cases, from clinical features and brain imaging findings to the genetic etiology.

A novel gene mutation in PANK2 in a patient with severe jaw-opening dystonia.

Pantothenate kinase-associated neurodegeneration (PKAN) is a rare neurodegenerative condition. Major clinical features include progressive dystonia, pigmentary retinopathy, spasticity, and cognitive decline. The typical MRI sign of the disease, known as "eye-of-the-tiger", is what makes differential diagnosis possible. We here describe a 16-year-old male patient with PKAN presenting with severe and sustained jaw-opening dystonia which may be due to heterogeneous etiologies showing poor response to treatment. Herein, long-term follow-up and genetic results of a PKAN case who experienced severe jaw-opening dystonia are presented and discussed.

[Neurodegeneration with brain iron accumulation]. / Neurodegeneration med jernakkumulation i hjernen

Neurodegeneration with brain iron accumulation (NBIA) is a heterogeneous group of syndromes. Whereas NBIA1 (panto-thenate kinase-associated neurodegeneration) has been known since 1922, some of the other diseases in the NBIA group have just been known for a few years. We present the case of a 16-year-old man who recently was diagnosed with NBIA4. He had had neurodegenerative symptoms since he was eight years old. The typical MRI findings in the basal ganglia were important in diagnosing NBIA. Furthermore gait analysis and specific genetic testing were performed.

123I-ioflupane SPECT findings of pantothenate kinase-associated neurodegeneration.

We present a case of a 72-year-old man with a 9-year history of memory decline and 7-year history of parkinsonian symptoms. An MRI demonstrated an "eye-of-the-tiger" sign in the basal ganglia, suggestive of pantothenate kinase-associated neurodegeneration (formerly known as Hallervorden-Spatz syndrome). An 123I-ioflupane SPECT scan demonstrated absence of radiotracer uptake in the caudate nuclei and putamina. Genetic testing confirmed a single-point mutation in the PANK2 gene, consistent with pantothenate kinase-associated neurodegeneration.