Type I neurodegeneration with brain iron accumulation, (NBIA-I,formerly Hallervorden-Spatz disease). Part II -- neuropathologic manifestation,novel genetic aspects and pathogenesis

In NBIA-1 major histopathological changes in the central nervous system are observed mostly in the subcortical pallido-nigral system. They consist in the presence of brown pigment deposits (containing iron), axonal spheroids, as well as Lewy neurities and cytoplasmic inclusions in the oligodendroglia (both the latter contain pathological alfa-synuclein). However, the histopathological pattern is most the diversified as regards the intensity and range of typical structural changes. The gene of the disease has been very recently identified and mapped on the short arm of the chromosome 20p13.-p12.3. The discovery of the NBIA-1 gene is a great advance in the search for a causal cure for this devastating disease. Its etiopathogenesis has not been fully explained yet. However, the gene identification allows to hypothesize that vitamin B5 metabolism may be disturbed at least in some NBIA-1 patients. Disturbance of vitamin B5 metabolism may cause an oxidative stress leading to degenerative and atrophic changes, most pronounced in the subcortical pallido-nigral system and in the retina.     

Neurodegeneration with brain iron accumulation: clinical, radiographic and genetic heterogeneity and corresponding therapeutic options

BACKGROUND: Neurodegeneration with brain iron accumulation (NBIA), formerly known as Hallervorden-Spatz syndrome, is a heterogeneous group of disorders with different treatment options. CASE REPORTS: In the first case, progressively generalizing dystonic symptoms appeared during childhood. A mutation in the gene encoding pantothenate kinase 2 (PANK2) was found. Brain MRI showed bilateral hypersignals within the globus pallidi on T2-weighted images. The patient was successfully treated by pallidal deep brain stimulation (DBS). In the second case an adult onset with parkinsonism was observed, for which no PANK2 mutation was found. T2-weighted brain MR images revealed multiple significant hyposignals (suggestive of iron deposits) localised in the cerebellar dentate nuclei and in the globi pallidi, the red nuclei and the substantia nigra. An antiparkinsonian treatment was proposed. CONCLUSION: The clinical, radiographic and genetic heterogeneity of NBIA has to be underlined.     

Neurodegeneration with brain iron accumulation: a diagnostic algorithm

The diagnosis of neurodegeneration with brain iron accumulation (NBIA) can be challenging, particularly given recent advances in NBIA genetics and clinical nosology. Although atypical cases continue to challenge physicians, by considering clinical features along with relevant neuroimaging findings, the diagnosis of NBIA can be made confidently. In addition, the identification of genetically distinct forms of NBIA allows clinicians to better provide prognostic and family counseling services to families and may have relevance in the near future as clinical trials become available. We describe a heuristic approach to NBIA diagnosis, identify important differential considerations, and demonstrate important neuroimaging features to aid in the diagnosis.     

Neurodegeneration with brain iron accumulation: A cautionary tale

Hallervorden and Spatz first described, in a sibship of 12, five sisters with clinically increasing dysarthria and progressive dementia, whose brains showed a brown discoloration of the globus pallidus and substantia nigra. Subsequently the basis has been shown to be a neurodegeneration with brain iron accumulation or pantothenate kinase-associated neurodegeneration due to mutations in the pantothenate kinase 2 (PANK2) gene. Progressive dystonia, Parkinsonism and dementia characterise the syndrome in children. The pathology comprises neuronal loss, axonal swelling, gliosis and iron deposits in the basal nuclei, disclosed by 'the eye of the tiger' sign on MR imaging. Since the criminal, unethical National Socialist activities of Hallervorden and Spatz came to light 'neurodegeneration with brain iron accumulation' has become the preferred nomenclature.     

Neurodegeneration with brain iron accumulation: from genes to pathogenesis

Neurodegeneration with brain iron accumulation comprises a clinically and genetically heterogeneous collection of disorders that share key features. These include progressive neurological disease accompanied by high basal ganglia iron and axonal dystrophy. To date, 2 genetic forms have been associated with mutations in PANK2 and PLA2G6, both of which encode proteins that are critical to membrane integrity. The intersection of pathways perturbed by defects in these 2 genes now enables us to test hypotheses of a common pathogenesis and ask why iron accumulates. The mechanisms implicated may contribute to our understanding of more common neurodegenerative disorders with iron dyshomeostasis, including Parkinson and Alzheimer disease.     

Subthalamic and pallidal oscillatory activity in patients with Neurodegeneration with Brain Iron Accumulation type I (NBIA-I)

ObjectivesNeurodegeneration with Brain Iron Accumulation type I (NBIA-I) is a rare hereditary neurodegenerative disorder with pallidal degeneration leading to disabling generalized dystonia and parkinsonism. Pallidal or subthalamic deep brain stimulation can partially alleviate motor symptoms. Disease-specific patterns of abnormally enhanced oscillatory neuronal activity recorded from the basal ganglia have been described in patients with movement disorders undergoing deep brain stimulation (DBS). Here we studied oscillatory activity recorded from the internal globus pallidus (GPi) and the subthalamic nucleus (STN) to characterize neuronal activity patterns in NBIA-I.MethodsWe recorded local field potentials (LFP) from DBS electrodes in 6 juvenile patients with NBIA-I who underwent functional neurosurgery. Four patients were implanted in the STN and two patients in the GPi. Recordings were performed during wakeful rest. An FFT-based approach was used to analyze the power spectrum in the target area.ResultsIn all patients we found distinct peaks in the low frequency (7–12 Hz) and in 5 out 6 also in the beta frequency range (15–30 Hz) with the largest beta peak in the patient that presented with the most prominent bradykinesia. No distinct peaks occurred in the gamma frequency range (35–100 Hz). The oscillatory pattern did not differ between STN and GPi.ConclusionsHere we show for the first time the oscillatory activity pattern in the STN and the GPi in juvenile patients with dystonia plus syndrome due to NBIA-I. The low frequency peak we found is in line with previous studies in patients with isolated idiopathic dystonia. In our cohort, the pallidal beta band activity may be related to more severe motor slowing in dystonia plus syndrome such as NBIA-I.SignificanceOur results further support the link between hyperkinetic motor symptoms such as dystonia and enhanced basal ganglia low frequency activity irrespective of the underlying etiology of dystonia.     

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

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

Neurodegeneration with brain iron accumulation: Characterization of clinical,radiological, and genetic features of pediatric patients from Southern India

BackgroundNeurodegeneration with brain iron accumulation (NBIA) is a group of rare inherited neurodegenerative disorders. Ten types of NBIA are known. Studies reporting various NBIA subtypes together are few. This study was aimed at describing clinical features, neuroimaging findings, and genetic mutations of different NBIA group disorders.MethodsClinical, radiological, and genetic data of patients diagnosed with NBIA in a tertiary care centre in Southern India from 2014 to 2020 was retrospectively collected and analysed.ResultsIn our cohort of 27 cases, PLA2G6-associated neurodegeneration (PLAN) was most common (n = 13) followed by Pantothenate kinase-associated neurodegeneration (PKAN) (n = 9). We had 2 cases each of Mitochondrial membrane-associated neurodegeneration (MPAN) and Beta-propeller protein- associated neurodegeneration (BPAN) and 1 case of Kufor-Rakeb Syndrome (KRS). Walking difficulty was the presenting complaint in all PKAN cases, whereas the presentation in PLAN was that of development regression with onset at a mean age of 2 years. Overall, 50% patients of them presented with development regression and one-third had epilepsy. Presence of pyramidal signs was most common examination feature (89%) followed by one or more eye findings (81%) and movement disorders (50%). Neuroimaging was abnormal in 24/27 cases and cerebellar atrophy was the commonest finding (52%) followed by globus pallidus hypointensities (44%).ConclusionsOne should have a high index of clinical suspicion for the diagnosis of NBIA in children presenting with neuroregression and vision abnormalities in presence of pyramidal signs or movement disorders. Neuroimaging and ophthalmological evaluation provide important clues to diagnosis in NBIA syndromes.     

Syndromes of neurodegeneration with brain iron accumulation (NBIA): an update on clinical presentations, histological and genetic underpinnings, and treatment considerations

In recent years, understanding of the syndromes of neurodegeneration with brain iron accumulation (NBIA) has grown considerably. In addition to the core syndromes of pantothenate kinsase-associated neurodegeneration (PKAN, NBIA1) and PLA2G6-associated neurodegeneration (PLAN, NBIA2), several other genetic causes have been identified. The acknowledged clinical spectrum has broadened, age-dependent presentations have been recognized, and we are becoming aware of overlap between the different NBIA disorders as well as with other diseases. Autopsy examination of genetically confirmed cases has demonstrated Lewy bodies and/or tangles in some subforms, bridging the gap to more common neurodegenerative disorders such as Parkinson's disease. NBIA genes map into related pathways, the understanding of which is important as we move toward mechanistic therapies. Our aim in this review is to provide an overview of not only the historical developments, clinical features, investigational findings, and therapeutic results but also the genetic and molecular underpinnings of the NBIA syndromes.     

Excess iron harms the brain: the syndromes of neurodegeneration with brain iron accumulation (NBIA)

Regulation of iron metabolism is crucial: both iron deficiency and iron overload can cause disease. In recent years, our understanding of the syndromes of Neurodegeneration with Brain Iron Accumulation (NBIA) continues to grow considerably. These are characterized by excessive iron deposition in the brain, mainly the basal ganglia. Pantothenate kinase-associated neurodegeneration (PKAN, NBIA1) and PLA2G6-associated neurodegeneration (PLAN, NBIA2) are the core syndromes, but several other genetic causes have been identified (including FA2H, C19orf12, ATP13A2, CP and FTL). These conditions show a wide clinical and pathological spectrum, with clinical overlap between the different NBIA disorders and other diseases including spastic paraplegias, leukodystrophies, and neuronal ceroid lipofuscinosis. Lewy body pathology was confirmed in some clinical subtypes (C19orf12-associated neurodegeneration and PLAN). Research aims at disentangling the various NBIA genes and their related pathways to move towards pathogenesis-targeted therapies. Until then treatment remains symptomatic. Here we will introduce the group of NBIA syndromes and review the main clinical features and investigational findings.     

Childhood disorders of neurodegeneration with brain iron accumulation (NBIA)

Neurodegeneration with brain iron accumulation (NBIA) comprises a heterogeneous group of progressive complex motor disorders characterized by the presence of high brain iron, particularly within the basal ganglia. A number of autosomal recessive NBIA syndromes can present in childhood, most commonly pantothenate kinase-associated neurodegeneration (PKAN; due to mutations in the PANK2 gene) and phospholipase A2 group 6-associated neurodegeneration (PLAN; associated with genetic defects in PLA2G6). Mutations in the genes that cause these two neuroaxonal dystrophies are thought to disrupt the normal cellular functions of phospholipid remodelling and fatty acid metabolism. A significant proportion of children with an NBIA phenotype have no genetic diagnosis and there are, no doubt, additional as yet undiscovered genes that account for a number of these cases. NBIA disorders can be diagnostically challenging as there is often phenotypic overlap between the different disease entities. This review aims to define the clinical, radiological, and genetic features of such disorders, providing the clinician with a stepwise approach to appropriate neurological and genetic investigation, as well as a clinical management strategy for these neurodegenerative syndromes.     

Coexistence of TDP‐43 and tau pathology in neurodegeneration with brain iron accumulation type 1 (NBIA‐1, formerly Hallervorden‐Spatz syndrome)

We report here an autopsy case of sporadic adult‐onset Hallervorden‐Spatz syndrome, also known as neurodegeneration with brain iron accumulation type 1 (NBIA1), without hereditary burden. A 49‐year‐old woman died after a 27‐year disease course. At the age of 22, she suffered from akinesia, resting tremor, and rigidity. At the age of 28, she was admitted to our hospital because of worsening parkinsonism and dementia. Within several years, she developed akinetic mutism. At the age of 49, she died of bleeding from a tracheostomy. Autopsy revealed a severely atrophic brain weighing 460 g. Histologically, there were iron deposits in the globus pallidus and substantia nigra pars reticulata, and numerous axonal spheroids in the subthalamic nuclei. Neurofibrillary tangles were abundant in the hippocampus, cerebral neocortex, basal ganglia, and brain stem. Neuritic plaques and amyloid deposits were absent. Lewy bodies and Lewy neurites, which are immunolabeled by anti‐α‐synuclein, were absent. We also observed the presence of TDP‐43‐positive neuronal perinuclear cytoplasmic inclusions, with variable frequency in the dentate gyrus granular cells, frontal and temporal cortices, and basal ganglia. TDP‐43‐positive glial cytoplasmic inclusions were also found with variable frequency in the frontal and temporal lobes and basal ganglia. The present case was diagnosed with adult‐onset NBIA‐1 with typical histological findings in the basal ganglia and brainstem. However, in this case, tau and TDP‐43 pathology was exceedingly more abundant than α‐synuclein pathology. This case contributes to the increasing evidence for the heterogeneity of NBIA‐1.     

ATP13A2 mutations (PARK9) cause neurodegeneration with brain iron accumulation

Kufor Rakeb disease (KRD, PARK9) is an autosomal recessive extrapyramidal‐pyramidal syndrome with generalized brain atrophy due to ATP13A2 gene mutations. We report clinical details and investigational results focusing on radiological findings of a genetically‐proven KRD case. Clinically, there was early onset levodopa‐responsive dystonia‐parkinsonism with pyramidal signs and eye movement abnormalities. Brain MRI revealed generalized atrophy and putaminal and caudate iron accumulation bilaterally. Our findings add KRD to the group of syndromes of neurodegeneration with brain iron accumulation (NBIA). KRD should be considered in patients with dystonia‐parkinsonism with iron on brain imaging and we suggest classifying as NBIA type 3. © 2010 Movement Disorder Society     

Review: Insights into molecular mechanisms of disease in neurodegeneration with brain iron accumulation: unifying theories

Neurodegeneration with brain iron accumulation (NBIA) is a group of disorders characterized by dystonia, parkinsonism and spasticity. Iron accumulates in the basal ganglia and may be accompanied by Lewy bodies, axonal swellings and hyperphosphorylated tau depending on NBIA subtype. Mutations in 10 genes have been associated with NBIA that include Ceruloplasmin (Cp) and ferritin light chain (FTL), both directly involved in iron homeostasis, as well as Pantothenate Kinase 2 (PANK2), Phospholipase A2 group 6 (PLA2G6), Fatty acid hydroxylase 2 (FA2H), Coenzyme A synthase (COASY), C19orf12, WDR45 and DCAF17 (C2orf37). These genes are involved in seemingly unrelated cellular pathways, such as lipid metabolism, Coenzyme A synthesis and autophagy. A greater understanding of the cellular pathways that link these genes and the disease mechanisms leading to iron dyshomeostasis is needed. Additionally, the major overlap seen between NBIA and more common neurodegenerative diseases may highlight conserved disease processes. In this review, we will discuss clinical and pathological findings for each NBIA‐related gene, discuss proposed disease mechanisms such as mitochondrial health, oxidative damage, autophagy/mitophagy and iron homeostasis, and speculate the potential overlap between NBIA subtypes.     

Tuberculous brain abscess: clinical presentation, pathophysiology and treatment (in children)

BACKGROUND: Tubercular brain abscess (TBA) is a rare manifestation of CNS tuberculosis. It is characterised by an encapsulated collection of pus, containing viable tubercular bacilli without evidence of tubercular granuloma.PRESENTATION AND HISTORY: Patients may present with features of raised intracranial pressure and focal neurological deficit commensurate with the site of the abscess. A history of pulmonary tuberculosis may be present, as documented in one of our six cases; three of our six children developed TBA despite 3-weeks to 12-month courses of antitubercular chemotherapy prescribed for post-TBM hydrocephalus.DIAGNOSIS: Contrast CT head, MRI, MR spectroscopy is helpful in making the diagnosis and planning the treatment. TBA may be unilocular or multilocular on contrast CT scan. A relatively long clinical history and an enhancing capsule with thick wall are suggestive of TBA. Pyogenic abscess, however, has a thin rim on contrast CT. The capsule of TBA is formed of vascular granulation tissue containing acute and chronic inflammatory cells, particularly polymorphs. Proof of tubercular origin must be demonstrated either by presence of acid fast bacilli in culture or staining of pus or wall.TREATMENT: Treatment options include simple puncture, continuous drainage, fractional drainage, repeated aspiration through a burr hole, stereotactic aspiration and total excision of the abscess. Total excision usually becomes necessary in multilocular noncommunicating and thick-walled abscesses. Antitubercular therapy is the mainstay of management. The development of fulminant tubercular meningitis is sometimes problematic following surgical excision of TBA, as seen in one of our four operated cases. Mortality is reported to be high despite progress in treatment, while five of the six children treated by us responded well to the treatment.     

Juvenile-onset generalized neuroaxonal dystrophy (Hallervorden-Spatz disease) with diffuse neurofibrillary and Lewy body pathology

We describe an unusual case of Hallervorden-Spatz disease (HSD). After presenting with limb rigidospasticity at the age of 9 years, our patient developed progressive dementia, spastic tetraparesis and myoclonic movements, leading to akinetic mutism. He died of pneumonia at the age of 39 years. Autopsy revealed a severely atrophic brain, weighing 510 g. Histologically, there were iron deposits in the globus pallidus and substantia nigra pars reticulata, and numerous axonal spheroids throughout the brain and spinal cord. Neurofibrillary tangles were abundant in the hippocampus, cerebral neocortex, basal ganglia and brain stem. Neuritic plaques and amyloid deposits were absent. Lewy bodies and Lewy neurites, which were immunolabeled by anti-α-synuclein, were found in the brain stem, cerebral cortex and spinal gray matter. Sarkosyl-insoluble tau extracted from the temporal cortex resolved on immunoblots into three major bands of 60, 64 and 68 kDa and a minor band of 72 kDa, as reported for Alzheimer’s disease. The present case, together with a few similar cases reported previously, may represent a particular subset of neuroaxonal dystrophy, i.e., HSD associated with extensive accumulation of both tau and α-synuclein. Received: 29 March 1999 / Revised, accepted: 1 July 1999     

Charcot—Marie—Tooth病的遗传,临床和电生理观察（附20例临床分析）

本文报道 ２０例 Ｃｈａｒｃｏｔ－Ｍａｒｉｅ－Ｔｏｏｔｈ病的遗传、临床和电生理资料。其中男 １６例,女 ４例,平均发病年龄为２６．７５岁。发现４例显性遗传,３例隐性遗传,１０例散发,３例遗传情况不详。主要症状有高弓足、垂足、鹤腿和腱反射消失;上肢前臂有肌萎缩者占１／４。所有病人电生理检查均有失神经现象,特别是ＭＣＶ有明显减慢。且发现ＭＣＶ的减慢和临床严重程度无相关联系。