Clinicopathological features of adult-onset neuronal intranuclear inclusion disease

Neurological disorders caused by novel non-coding repeat expansions: clinical features and differential diagnosis

Nucleotide repeat expansions in the human genome are a well-known cause of neurological disease. In the past decade, advances in DNA sequencing technologies have led to a better understanding of the role of non-coding DNA, that is, the DNA that is not transcribed into proteins. These techniques have also enabled the identification of pathogenic non-coding repeat expansions that cause neurological disorders. Mounting evidence shows that adult patients with familial or sporadic presentations of epilepsy, cognitive dysfunction, myopathy, neuropathy, ataxia, or movement disorders can be carriers of non-coding repeat expansions. The description of the clinical, epidemiological, and molecular features of these recently identified non-coding repeat expansion disorders should guide clinicians in the diagnosis and management of these patients, and help in the genetic counselling for patients and their families.

Mapping macrostructural and microstructural brain alterations in patients with neuronal intranuclear inclusion disease

BACKGROUND AND PURPOSE

Neuronal intranuclear inclusion disease (NIID) is a rare complex neurodegenerative disorder presents with various radiological features. The study aimed to investigate the structural abnormalities in NIID using multi-shell diffusion MR.

MATERIALS AND METHODS

Twenty-eight patients with adult-onset NIID and 32 healthy controls were included. Volumetric and diffusion MRI measures, including volume, fractional anisotropy (FA), mean diffusivity (MD), intracellular volume fraction (ICVF), orientation dispersion index (ODI), and isotropic volume fraction (ISOVF) of six brain structures, including cortex, subcortical GM, cerebral WM, cerebellar GM and WM, and brainstem, were obtained and compared between NIID and healthy controls. Associations between MRI measures and clinical variables were investigated.

RESULTS

Brain lesions of NIID included corticomedullary junction lesions on DWI, confluent leukoencephalopathy, lesions on callosum, cerebellar middle peduncle, cerebellar paravermal area and brainstem, and brain atrophy. Compared to healthy controls, NIID showed extensive volume loss of all the six brain regions (all p < 0.001); lower FA in cerebral WM (p < 0.001); higher MD in all WM regions; lower ODI in cortex (p < 0.001); higher ODI in subcortical GM (p < 0.001) and brainstem (p = 0.016); lower ICVF in brainstem (p = 0.001), and cerebral WM (p < 0.001); higher ISOVF in all the brain regions (p < 0.001). Higher MD of cerebellar WM was associated with worse cognitive level as evaluated by MoCA scores (p = 0.011).

CONCLUSIONS

NIID patients demonstrated widespread brain atrophy but heterogeneous diffusion alterations. Cerebellar WM integrity impairment was correlated with the cognitive decline. The findings of the current study offer a sophisticated picture of brain structural alterations in NIID.

Prevalence and Characterization of NOTCH2NLC GGC Repeat Expansions in Koreans: From a Hospital Cohort Analysis to a Population-Wide Study

Background and Objectives

GGC repeat expansions in the NOTCH2NLC gene are associated with a broad spectrum of progressive neurologic disorders, notably, neuronal intranuclear inclusion disease (NIID). We aimed to investigate the population-wide prevalence and clinical manifestations of NOTCH2NLC-related disorders in Koreans.

Methods

We conducted a study using 2 different cohorts from the Korean population. Patients with available brain MRI scans from Seoul National University Hospital (SNUH) were thoroughly reviewed, and NIID-suspected patients presenting the zigzag edging signs underwent genetic evaluation for NOTCH2NLC repeats by Cas9-mediated nanopore sequencing. In addition, we analyzed whole-genome sequencing data from 3,887 individuals in the Korea Biobank cohort to estimate the distribution of the repeat counts in Koreans and to identify putative patients with expanded alleles and neurologic phenotypes.

Results

In the SNUH cohort, among 90 adult-onset leukoencephalopathy patients with unknown etiologies, we found 20 patients with zigzag edging signs. Except for 2 diagnosed with fragile X-associated tremor/ataxia syndrome and 2 with unavailable samples, all 16 patients (17.8%) were diagnosed with NIID (repeat range: 87-217). By analyzing the Korea Biobank cohort, we estimated the distribution of repeat counts and threshold (>64) for Koreans, identifying 6 potential patients with NIID. Furthermore, long-read sequencing enabled the elucidation of transmission and epigenetic patterns of NOTCH2NLC repeats within a family affected by pediatric-onset NIID.

Discussion

This study presents the population-wide distribution of NOTCH2NLC repeats and the estimated prevalence of NIID in Koreans, providing valuable insights into the association between repeat counts and disease manifestations in diverse neurologic disorders.

Unusual combinations of neurodegenerative pathologies with chronic traumatic encephalopathy (CTE) complicates clinical prediction of CTE

BACKGROUND AND PURPOSE

Chronic traumatic encephalopathy (CTE) has gained widespread attention due to its association with multiple concussions and contact sports. However, CTE remains a postmortem diagnosis, and the link between clinical symptoms and CTE pathology is poorly understood. This study aimed to investigate the presence of copathologies and their impact on symptoms in former contact sports athletes.

METHODS

This was a retrospective case series design of 12 consecutive cases of former contact sports athletes referred for autopsy. Analyses are descriptive and include clinical history as well as the pathological findings of the autopsied brains.

RESULTS

All participants had a history of multiple concussions, and all but one had documented progressive cognitive, psychiatric, and/or motor symptoms. The results showed that 11 of the 12 participants had evidence of CTE in the brain, but also other copathologies, including different combinations of tauopathies, and other rare entities.

CONCLUSIONS

The heterogeneity of symptoms after repetitive head injuries and the diverse pathological combinations accompanying CTE complicate the prediction of CTE in clinical practice. It is prudent to consider the possibility of multiple copathologies when clinically assessing patients with repetitive head injuries, especially as they age, and attributing neurological or cognitive symptoms solely to presumptive CTE in elderly patients should be discouraged.

Neuronal intranuclear inclusion disease in New Zealand: A novel discovery

Neuronal intranuclear inclusion disease, caused by a GGC repeat expansion in the 5'-untranslated region of NOTCH2NLC, is a rare neurodegenerative condition with highly variable clinical manifestations. In recent years, the number of reported cases have increased dramatically in East Asia. We report the first four genetically confirmed cases of neuronal intranuclear inclusion disease in New Zealand, all having Polynesian ancestry (three New Zealand Māori and one Cook Island Māori). Phenotypically, they resemble cases reported from recent large East Asian cohorts.

Reversible encephalitis-like episodes in fragile X-associated tremor/ataxia syndrome: a case report

BACKGROUND

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder caused by CGG repeat expansion of FMR1 gene. Both FXTAS and neuronal intranuclear inclusion disease (NIID) belong to polyglycine diseases and present similar clinical, radiological, and pathological features, making it difficult to distinguish these diseases. Reversible encephalitis-like attacks are often observed in NIID. It is unclear whether they are presented in FXTAS and can be used for differential diagnosis of NIID and FXTAS.

CASE PRESENTATION

A 63-year-old Chinese male with late-onset gait disturbance, cognitive decline, and reversible attacks of fever, consciousness impairment, dizziness, vomiting, and urinary incontinence underwent neurological assessment and examinations, including laboratory tests, electroencephalogram test, imaging, skin biopsy, and genetic test. Brain MRI showed T2 hyperintensities in middle cerebellar peduncle and cerebrum, in addition to cerebellar atrophy and DWI hyperintensities along the corticomedullary junction. Lesions in the brainstem were observed. Skin biopsy showed p62-positive intranuclear inclusions. The possibilities of hypoglycemia, lactic acidosis, epileptic seizures, and cerebrovascular attacks were excluded. Genetic analysis revealed CGG repeat expansion in FMR1 gene, and the number of repeats was 111. The patient was finally diagnosed as FXTAS. He received supportive treatment as well as symptomatic treatment during hospitalization. His encephalitic symptoms were completely relieved within one week.

CONCLUSIONS

This is a detailed report of a case of FXTAS with reversible encephalitis-like episodes. This report provides new information for the possible and rare features of FXTAS, highlighting that encephalitis-like episodes are common in polyglycine diseases and unable to be used for differential diagnosis.

Ultra-high-field 7-Tesla magnetic resonance imaging in fragile X tremor/ataxia syndrome (FXTAS)

Fragile X tremor/ataxia syndrome (FXTAS) is an adult-onset neurodegenerative disorder characterized by premutation expansion of fragile X mental retardation 1 (FMR1) gene. It is a common single-gene cause of tremor, ataxia, and cognitive decline in adults. FXTAS affects the central, peripheral and autonomic nervous systems, leading to a range of neurological symptoms from dementia to dysautonomia. A characteristic imaging feature of FXTAS is symmetric T2 hyperintensity in the deep white matter of the cerebellar hemispheres and middle cerebral peduncle. However, recent studies have reported additional findings on diffusion weighted images (DWI), such as a symmetric high-intensity band-like signal at the cerebral corticomedullary junction. These findings, along with the characteristic cerebellar signal alterations, overlap with imaging findings seen in adult-onset neuronal intranuclear inclusion disease (NIID). Importantly, recent pathology studies have shown that both FXTAS and NIID can manifest intranuclear inclusion bodies, posing a diagnostic challenge and potential for misdiagnosis. We describe a 58-year-old man with FXTAS who received an erroneous diagnosis based on imaging and histopathology results. We emphasize the potential pitfalls in distinguishing NIID from FXTAS and stress the importance of genetic analysis in all cases with suspected NIID and FXTAS for confirmation. Additionally, we present the 7T MRI brain findings of FXTAS.

Clinical features of neuronal intranuclear inclusion disease with seizures: a systematic literature review

Background

Infant, junior, and adult patients with neuronal intranuclear inclusion disease (NIID) present with various types of seizures. We aimed to conduct a systematic literature review on the clinical characteristics of NIID with seizures to provide novel insight for early diagnosis and treatment and to improve prognosis of these patients.

Methods

We used keywords to screen articles related to NIID and seizures, and data concerning the clinical characteristics of patients, including demographic features, disease characteristics of the seizures, treatment responses, imaging examinations, and other auxiliary examination results were extracted.

Results

The included studies comprised 21 patients with NIID with seizures. The most common clinical phenotypes were cognitive impairment (76.20%) and impaired consciousness (57.14%), and generalized onset motor seizures (46.15%) represented the most common type. Compared with infantile and juvenile cases, the use of antiepileptic drugs in adults led to significant seizure control and symptom improvement, in addition to providing a better prognosis. The number of GGC sequence repeats in the NOTCH2NLC gene in six NIID patients with seizures who underwent genetic testing ranged 72-134.

Conclusion

The most common clinical phenotypes in patients with NIID with seizures were cognitive impairment and consciousness disorders. Patients with NIID presented with various types of seizures, with the most common being generalized onset motor seizures. Adult patients had a better prognosis and were relatively stable. The early diagnosis of NIID with seizures is of great significance for treatment and to improve prognosis.

Investigating Repeat Expansions in NIPA1, NOP56, and NOTCH2NLC Genes: A Closer Look at Amyotrophic Lateral Sclerosis Patients from Southern Italy

The discovery of hexanucleotide repeats expansion (RE) in Chromosome 9 Open Reading frame 72 (C9orf72) as the major genetic cause of amyotrophic lateral sclerosis (ALS) and the association between intermediate repeats in Ataxin-2 (ATXN2) with the disorder suggest that repetitive sequences in the human genome play a significant role in ALS pathophysiology. Investigating the frequency of repeat expansions in ALS in different populations and ethnic groups is therefore of great importance. Based on these premises, this study aimed to define the frequency of REs in the NIPA1, NOP56, and NOTCH2NLC genes and the possible associations between phenotypes and the size of REs in the Italian population. Using repeat-primed-PCR and PCR-fragment analyses, we screened 302 El-Escorial-diagnosed ALS patients and compared the RE distribution to 167 age-, gender-, and ethnicity-matched healthy controls. While the REs distribution was similar between the ALS and control groups, a moderate association was observed between longer RE lengths and clinical features such as age at onset, gender, site of onset, and family history. In conclusion, this is the first study to screen ALS patients from southern Italy for REs in NIPA1, NOP56, and NOTCH2NLC genes, contributing to our understanding of ALS genetics. Our results highlighted that the extremely rare pathogenic REs in these genes do not allow an association with the disease.

Plasma neurofilament light as a promising biomarker in neuronal intranuclear inclusion disease

Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disorder lacking reliable biomarkers. This study investigates plasma protein levels as potential biomarkers of disease severity and progression in NIID. In this study, we enrolled 30 NIID patients and 36 age- and sex-matched controls, following them for 1-2 years. Plasma neurofilament light (NfL), glial fibrillary acidic protein (GFAP), ubiquitin carboxy-terminal hydrolase L1 (UCH-L1), and tau were measured using ultrasensitive single molecule array (Simoa) assays. Disease severity was evaluated with the Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), Activities of Daily Living (ADL), and CNS symptom counts, in addition to neuroimaging data. Our study revealed that NIID patients has significantly higher plasma NfL (median, 35.2 vs. 8.61 pg/mL, p < 0.001) and GFAP (102 vs. 79.0 pg/mL, p = 0.010) levels compared to controls, with NfL emerging as a robust diagnostic marker (AUC = 0.956). NfL levels were notably higher in acute-onset NIID (77.5 vs. 28.8 pg/mL, p = 0.001). NfL correlated strongly with disease severity, including MMSE (ρ = - 0.687, p < 0.001), MoCA (ρ = - 0.670, p < 0.001), ADL (ρ = 0.587, p = 0.001), CNS symptoms (ρ = 0.369, p = 0.045), and white matter hyperintensity volume (ρ = 0.620, p = 0.004). Higher baseline NfL (≥ 35.2 pg/mL) associated with increased ADL scores, CNS symptoms, and white matter hyperintensity at follow-up. UCH-L1 and total tau levels showed no significant differences. Our results suggested the potential of NfL as a promising biomarker of disease severity and progression in NIID.

Review of Phenotypic Heterogeneity of Neuronal Intranuclear Inclusion Disease and NOTCH2NLC-Related GGC Repeat Expansion Disorders

Neuronal intranuclear inclusion disease (NIID) is an underdiagnosed neurodegenerative disorder caused by pathogenic GGC expansions in NOTCH2NLC. However, an increasing number of reports of NOTCH2NLC GGC expansions in patients with Alzheimer disease, essential tremor, Parkinson disease, amyotrophic lateral sclerosis, and oculopharyngodistal myopathy have led to the proposal of a new concept known as NOTCH2NLC-related GGC repeat expansion disorders (NREDs). The majority of studies have mainly focused on screening for NOTCH2NLC GGC repeat variation in populations previously diagnosed with the associated disease, subsequently presenting it as a novel causative gene for the condition. These studies appear to be clinically relevant but do have their limitations because they may incorrectly regard the lack of MRI abnormalities as an exclusion criterion for NIID or overlook concomitant clinical presentations not typically observed in the associated diseases. Besides, in many instances within these reports, patients lack pathologic evidence or undergo long-term follow-up to conclusively rule out NIID. In this review, we will systematically review the research on NOTCH2NLC 5' untranslated region GGC repeat expansions and their association with related neurologic disorders, explaining the limitations of the relevant reports. Furthermore, we will integrate subsequent studies to further demonstrate that these patients actually experienced distinct clinical phenotypes of NIID.

Chronic traumatic encephalopathy neuropathologic change in former Australian rugby players

AIMS

We applied the 2021 consensus criteria for both chronic traumatic encephalopathy neuropathological change and traumatic encephalopathy syndrome in a small case series of six former elite-level Australian rugby code players.

METHODS

Neuropathological assessment of these cases was carried out at the Sydney and Victorian Brain Banks. Clinical data were collected via clinical interviews and health questionnaires completed by the participants and/or their next of kin, and neuropsychological testing was conducted with participants who were capable of completing this testing.

RESULTS

All cases exhibited progressive cognitive impairment during life. Chronic traumatic encephalopathy neuropathological change was identified in four out of the six cases. However, coexisting neuropathologies were common, with limbic-predominant age-related TDP-43 encephalopathy and ageing-related tau astrogliopathy seen in all cases, intermediate or high Alzheimer's disease neuropathological change seen in four cases and hippocampal sclerosis seen in two of the six cases.

CONCLUSION

The presence of multiple neuropathologies in these cases complicates clinical diagnostic efforts for traumatic encephalopathy syndrome. It will be important for further clinicopathological studies on larger groups to report all neuropathological comorbidities found in cases diagnosed with either chronic traumatic encephalopathy neuropathological change and/or traumatic encephalopathy syndrome.

Encephalitis-like episodes with cortical edema and enhancement in patients with neuronal intranuclear inclusion disease

OBJECTIVES

Neuronal intranuclear inclusion disease (NIID) exhibited significant clinical heterogeneities. However, the clinical features, radiographic changes, and prognosis of patients with encephalitis-like NIID have yet to be systematically elucidated.

METHODS

Clinical data including medical history, physical examination, and laboratory examinations were collected and analyzed. Skin and sural nerve biopsies were conducted on the patient. Repeat-primed PCR (RP-PCR) and fluorescence amplicon length PCR (AL-PCR) were used to detect the expansion of CGG repeat. We also reviewed the clinical and genetic data of NIID patients with cortical enhancement.

RESULTS

A 54-year-old woman presented with encephalitis-like NIID, characterized by severe headache and agitative psychiatric symptoms. The brain MRI showed cortical swelling in the temporo-occipital lobes and significant enhancement of the cortical surface and dura, but without hyperintensities along the corticomedullary junction on diffusion-weighted image (DWI). A biopsy of the sural nerve revealed a demyelinating pathological change. The intranuclear inclusions were detected in nerve and skin tissues using the p62 antibody and electron microscopy. RP-PCR and AL-PCR unveiled the pathogenic expansion of CGG repeats in the NOTCH2NLC gene. A review of the literature indicated that nine out of the 16 patients with cortical lesions and linear enhancement exhibited encephalitis-like NIID.

CONCLUSION

This study indicated that patients with encephalitis-like NIID typically exhibited headache and excitatory psychiatric symptoms, often accompanied by cortical edema and enhancement of posterior lobes, and responded well to glucocorticoid treatment. Furthermore, some patients may not exhibit hyperintensities along the corticomedullary junction on DWI, potentially leading to misdiagnosis.

[Recent clinical advances in hereditary spinocerebellar degeneration]

Spinocerebellar degeneration (SCD) is a neurodegenerative disorder characterized by cerebellar ataxia and other multisystem manifestations, such as Parkinsonism and pyramidal tract symptoms. No effective treatment is available for SCD. Approximately one-third of the cases of SCD are inherited, and the remaining two-third are sporadic, including multiple system atrophy. This article provides an overview of hereditary SCD, its clinical features, recent treatment advances, biomarkers, role of genomic medicine, and future treatment prospects.

The predominance of "astrocytic" intranuclear inclusions in neuronal intranuclear inclusion disease manifesting encephalopathy-like symptoms: A case series with brain biopsy

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disorder represented by eosinophilic intranuclear inclusions (EIIs) and GGC/CGG repeat expansion in the NOTCH2NLC gene. We report here two adult cases of NIID, genetically confirmed, with manifestation of encephalopathy-like symptoms and address the histopathologic findings obtained by brain biopsies, with a focus on "astrocytic" intranuclear inclusions (AIIs). Case 1 presented with paroxysmal restlessness, vertigo, or fever and was later involved in severe dementia and tetraparesis. Case 2 presented with forgetfulness and then with paroxysmal fever and headache. In both cases, delimited areas with gadolinium enhancement on magnetic resonance imaging and corresponding hyperperfusion were detected, leading to brain biopsies of the cortex. On histology, Case 1 showed an abnormal lamination, where the thickness of layers was different from usual. Both neurons and astrocytes showed some dysmorphologic features. Notably, astrocytes rather than neurons harbored EIIs. Case 2 showed a cortex, where neurons tended to be arrayed in a columnar fashion. Astrocytes showed some dysmorphologic features. Notably, much more astrocytes than neurons harbored EIIs. By a double-labeling immunofluorescence study for p62/NeuN and p62/glial fibrillary acidic protein, the predominance of AIIs was confirmed in both cases. Considering the physiological functions of astrocytes for the development and maintenance of the cortex, the encephalopathy-like symptoms, dynamic change of cerebral blood flow, and cortical dysmorphology can reasonably be explained by the dysfunction of EII-bearing astrocytes rather than EII-bearing neurons. This study suggests the presence of a subtype of NIID where AIIs rather than "neuronal" intranuclear inclusions are likely a key player in the pathogenesis of NIID, particularly in cases with encephalopathy-like symptoms. The importance of AIIs ("gliopathy") should be more appreciated in future studies of NIID.

Neuronal intranuclear inclusion disease misdiagnosed as Parkinson's disease: a case report

Neuronal intranuclear inclusion disease (NIID) is a rare progressive neurodegenerative disease that mainly manifests as dementia, muscle weakness, sensory disturbances, and autonomic nervous dysfunction. Herein, we report a 68-year-old Chinese woman who was hospitalized because of resting tremor and bradykinesia that had been present for 7 years. Five years prior, bradykinesia and hypermyotonia had become apparent. She had urinary incontinence and rapid eye movement sleep behavior disorder. She was diagnosed with Parkinson's disease (PD) and received levodopa and pramipexole, which relieved her motor symptoms. During hospitalization, diffusion-weighted imaging revealed a high-intensity signal along the cortical medullary junction. Moreover, a skin biopsy revealed the presence of intranuclear inclusions in adipocytes, fibroblasts, and sweat gland cells. NIID was diagnosed by testing the Notch 2 N-terminal-like C (NOTCH2NLC) gene. We report this case to remind doctors to consider NIID when diagnosing patients with symptoms indicative of Parkinson's disease. Moreover, we note that further research is needed on the mechanism by which levodopa is effective for NIID.

Neuronal Intranuclear Inclusion Disease with NOTCH2NLC GGC Repeat Expansion: A Systematic Review and Challenges of Phenotypic Characterization

Neuronal intranuclear inclusion disease (NIID) is a highly clinically heterogeneous neurodegenerative disorder primarily attributed to abnormal GGC repeat expansions in the NOTCH2NLC gene. This study aims to comprehensively explore its phenotypic characteristics and genotype-phenotype correlation. A literature search was conducted in PubMed, Embase, and the Cochrane Library from September 1, 2019, to December 31, 2022, encompassing reported NIID cases confirmed by pathogenic NOTCH2NLC mutations. Linear regressions and trend analyses were performed. Analyzing 635 cases from 85 included studies revealed that familial cases exhibited significantly larger GGC repeat expansions than sporadic cases (p < 0.001), and this frequency significantly increased with expanding GGC repeats (p trend < 0.001). Age at onset (AAO) showed a negative correlation with GGC repeat expansions (p < 0.001). The predominant initial symptoms included tremor (31.70%), cognitive impairment (14.12%), and muscle weakness (10.66%). The decreased or absent tendon reflex (DTR/ATR) emerged as a notable clinical indicator of NIID due to its high prevalence. U-fiber was observed in 79.11% of patients, particularly prominent in paroxysmal disease-dominant (87.50%) and dementia-dominant cases (81.08%). Peripheral neuropathy-dominant cases exhibited larger GGC repeat expansions (median = 123.00) and an earlier AAO (median = 33.00) than other phenotypes. Moreover, a significant genetic anticipation of 3.5 years was observed (p = 0.039). This study provides a comprehensive and up-to-date compilation of genotypic and phenotypic information on NIID since the identification of the causative gene NOTCH2NLC. We contribute a novel diagnostic framework for NIID to support clinical practice.

Case report: Neuronal intranuclear inclusion disease initially mimicking reversible cerebral vasoconstriction syndrome: serial neuroimaging findings during an 11-year follow-up

Neuronal intranuclear inclusion disease (NIID) is a rare, progressive neurodegenerative disorder known for its diverse clinical manifestations. Although episodic neurogenic events can be associated with NIID, no reported cases have demonstrated concurrent clinical features or MRI findings resembling reversible cerebral vasoconstriction syndrome (RCVS). Here, we present the inaugural case of an adult-onset NIID patient who initially displayed symptoms reminiscent of RCVS. The 59-year-old male patient's initial presentation included a thunderclap headache, right visual field deficit, and confusion. Although his brain MRI appeared normal, MR angiography unveiled left posterior cerebral artery occlusion, subsequently followed by recanalization, culminating in an RCVS diagnosis. Over an 11-year period, the patient encountered 10 additional episodes, each escalating in duration and intensity, accompanied by seizures. Simultaneously, cognitive impairment progressed. Genetic testing for NIID revealed an abnormal expansion of GGC repeats in NOTCH2NLC, with a count of 115 (normal range, <60), and this patient was diagnosed with NIID. Our report highlights that NIID can clinically and radiologically mimic RCVS. Therefore, in the differential diagnosis of RCVS, particularly in cases with atypical features or recurrent episodes, consideration of NIID is warranted. Additionally, the longitudinal neuroimaging findings provided the course of NIID over an 11-year follow-up period.

CGG repeat expansion in LOC642361/NUTM2B-AS1 typically presents as oculopharyngodistal myopathy

CGG repeat expansions in LOC642361/NUTM2B-AS1 have recently been identified as a cause of oculopharyngeal myopathy with leukoencephalopathy. However, since only three patients from a single family were reported, it remains unknown whether their clinicopathological features are typical for CGG repeat expansions in LOC642361/NUTM2B-AS1. Here, using repeat-primed-polymerase chain reaction and long-read sequencing, we identify 12 individuals from 3 unrelated families with CGG repeat expansions in LOC642361/NUTM2B-AS1, typically presenting with oculopharyngodistal myopathy. The CGG repeat expansions range from 161 to 669 repeat units. Most of the patients present with ptosis, restricted eye movements, dysphagia, dysarthria, and diffuse limb muscle weakness. Only one patient shows T2-weighted hyperintensity in the cerebellar white matter surrounding the deep cerebellar nuclei on brain magnetic resonance imaging. Muscle biopsies from three patients show a myopathic pattern and rimmed vacuoles. Analyses of muscle biopsies suggest that CGG repeat expansions in LOC642361/NUTM2B-AS1 may deleteriously affect aggrephagic capacity, suggesting that RNA toxicity and mitochondrial dysfunction may contribute to pathogenesis. Our study thus expands the phenotypic spectrum for the CGG repeat expansion of LOC642361/NUTM2B-AS1 and indicates that this genetic variant typically manifests as oculopharyngodistal myopathy with chronic myopathic changes with rimmed vacuoles and filamentous intranuclear inclusions in muscle fibers.

Recovery after Prolonged Disturbance of Consciousness and Repeated Cerebral Perfusion Changes in Neuronal Intranuclear Inclusion Disease

Encephalitic episodes are a clinical manifestation of neuronal intranuclear inclusion disease (NIID) and often show transient disturbance of consciousness. We herein report a genetically confirmed patient with NIID who initially presented progressive dementia and showed prolonged disturbance of consciousness preceded by an acute-onset headache. During that time, we performed N-isopropyl-p-[123I] iodoamphetamine single-photon-emission computed tomography twice and found that the blood flow increased in different regions. Prolonged disturbance of consciousness following an encephalitic episode may be associated with repeated hyperperfusion in various regions resulting from mitochondrial dysfunction. NIID patients presenting with encephalitic episodes can recover gradually and spontaneously even after prolonged disturbances of consciousness.

Adult-onset neuronal intranuclear inclusion disease related retinal degeneration: a Chinese case series

Purpose

To evaluate adult-onset neuronal intranuclear inclusion disease (NIID)-related retinopathy with guanine-guanine-cytosine repeat expansions in NOTCH2NLC.

Materials and methods

Neuro-ophthalmic evaluations, including best-corrected visual acuity, slit-lamp biomicroscopy, intraocular pressure (IOP), ultrasound biomicroscopy, pupillometry, fundus photography, fundus autofluorescence (FAF), optical coherence tomography (OCT), Humphrey visual field, full-field electroretinography (ERG), and multifocal ERG (mf-ERG) were performed in patients with gene-proven NIID.

Results

Nine patients (18 eyes) were evaluated, with a median age of 62 years (55-68) and only one man was included in our study. Six patients presented with decreased visual acuity or night blindness, whereas the other three were asymptomatic. The visual acuity was measured from 20/200 to 20/20. Miosis was present in eight patients, four of whom had ciliary process hypertrophy and pronation, and three of whom had shallow anterior chambers. Fundus photography, FAF, and OCT showed consistent structural abnormalities mainly started from peripapillary areas and localized in the outer layer of photoreceptors and inner ganglion cell layer. ERG and mf-ERG also revealed retinal dysfunction in the corresponding regions.

Conclusion

Patients with NIID showed both structural and functional retinopathies which were unique and different from common cone-rod dystrophy or retinitis pigmentosa. Patients with miosis may have a potential risk of an angle-closure glaucoma attack. Neuro-ophthalmic evaluations is essential for evaluating patients with NIID, even without visual symptom.

Neuronal intranuclear inclusion disease with cortical involvement in left hemisphere: a case report

BACKGROUND

Neuronal intranuclear inclusion disease (NIID) is a rare highly heterogeneous disease. In this paper, we present a case of NIID featured in cortical involvement in left hemisphere of brain and the imaging changes in the process of the disease.

CASE PRESENTATION

A 57-year-old female was hospitalized due to recurrent attacks of headache with cognitive impairment and tremor for 2 years. The symptoms of headache episodes were reversible. The characteristic radiologic change was high intensity signal involving the grey matter-white matter junction on the brain diffusion-weighted imaging (DWI), which existed in the frontal lobe and then extended backwards. Atypical features on fluid-attenuated inversion recovery (FLAIR) sequences showing small patchy high signals in the cerebellar vermis. High signals and edema were detected on FLAIR images along the cortex of the left occipito-parieto-temporal lobes, expanding and gradually shrinking in the follow-up visit. Besides, cerebral atrophy and bilateral symmetrical leukoencephalopathy were also detected. Skin biopsy and genetic testing confirmed the diagnosis of NIID.

CONCLUSION

Except for typical radiological change strongly suggesting NIID, it is also necessary to notice the insidious symptoms of NIID combining with some atypical imaging features to make an early diagnosis. Skin biopsies or genetic testing should be carried out early in patients with highly suspected NIID.

Pathologic changes in neuronal intranuclear inclusion disease are linked to aberrant FUS interaction under hyperosmotic stress

CGG repeat expansion in NOTCH2NLC is the genetic cause of neuronal intranuclear inclusion disease (NIID). Previous studies indicated that the CGG repeats can be translated into polyglycine protein (N2CpolyG) which was toxic to neurons by forming intranuclear inclusions (IIs). However, little is known about the factors governing polyG IIs formation as well as its molecular pathogenesis. Considering that neurogenetic disorders usually involve interactions between genetic and environmental stresses, we investigated the effect of stress on the formation of IIs. Our results revealed that under hyperosmotic stress, N2CpolyG translocated from the cytoplasm to the nucleus and formed IIs in SH-SY5Y cells, recapitulating the pathological hallmark of NIID patients. Furthermore, N2CpolyG interacted/ co-localized with an RNA-binding protein FUS in the IIs of cellular model and NIID patient tissues, thereby disrupting stress granule formation in cytoplasm under hyperosmotic stress. Consequently, dysregulated expression of microRNAs was found both in NIID patients and cellular model, which could be restored by FUS overexpression in cultured cells. Overall, our findings indicate a mechanism of stress-induced pathological changes as well as neuronal damage, and a potential strategy for the treatment of NIID.

Comorbidity of Dementia: A Cross-Sectional Study of PUMCH Dementia Cohort

BACKGROUND

Comorbidities reduce quality of life for people with dementia and caregivers. Some comorbidities share a genetic basis with dementia.

OBJECTIVE

The objective of this study is to assess comorbidity in patients with different dementia subtypes in order to better understand the pathogenesis of dementias.

METHODS

A total of 298 patients with dementia were included. We collected some common comorbidities. We analyzed the differences in comorbidities among patients with dementia according to clinical diagnosis, age of onset (early-onset: < 65 and late-onset: ≥65 years old) and apolipoprotein (APOE) genotypes by using the univariate and multivariate approaches.

RESULTS

Among 298 participants, there were 183 Alzheimer's disease (AD), 40 vascular dementia (VaD), 37 frontotemporal dementia (FTLD), 20 Lewy body dementia (LBD), and 18 other types of dementia. Based on age of onset, 156 cases had early-onset dementia and 142 cases had late-onset dementia. The most common comorbidities observed in all dementia patients were hyperlipidemia (68.1%), hypertension (39.9%), insomnia (21.1%), diabetes mellitus (19.5%), and hearing impairment (18.1%). The prevalence of hypertension and cerebrovascular disease was found to be higher in patients with VaD compared to those with AD (p = 0.002, p < 0.001, respectively) and FTLD (p = 0.028, p = 0.004, respectively). Additionally, patients with late-onset dementia had a higher burden of comorbidities compared to those with early-onset dementia. It was observed that APOE ɛ4/ɛ4 carriers were less likely to have insomnia (p = 0.031).

CONCLUSIONS

Comorbidities are prevalent in patients with dementia, with hyperlipidemia, hypertension, insomnia, diabetes, and hearing impairment being the most commonly observed. Comorbidity differences existed among different dementia subtypes.

Utility of labial salivary gland biopsy in the histological diagnosis of neuronal intranuclear inclusion disease

BACKGROUND AND PURPOSE

Neuronal intranuclear inclusion disease (NIID) poses a diagnostic challenge because of its diverse clinical manifestations. Detection of intranuclear inclusions remains the primary diagnostic criterion for NIID. Skin biopsies have traditionally been used, but concerns exist regarding postoperative complications and scarring. We sought to investigate the diagnostic utility of labial salivary gland biopsy, a less invasive alternative.

METHODS

This study included a total of 19 patients and 11 asymptomatic carriers who underwent labial gland biopsies, while 10 patients opted for skin biopsies. All these individuals were confirmed to have pathogenic GGC repeat expansions in the NOTCH2NLC gene. The control group comprised 20 individuals matched for age and sex, all with nonpathogenic GGC repeat expansions, and their labial gland tissue was sourced from oral surgery specimens.

RESULTS

Labial gland biopsies proved to be a highly effective diagnostic method in detecting eosinophilic intranuclear inclusions in NIID patients. The inclusions showed positive staining for p62 and ubiquitin, confirming their pathological significance. The presence of uN2CpolyG protein in the labial gland tissue further supported the diagnosis. Importantly, all patients who underwent lip gland biopsy experienced fast wound healing without any noticeable scarring. In contrast, skin biopsies led to varying degrees of scarring and one instance of a localized infection.

CONCLUSION

Labial salivary gland biopsy emerged as a minimally invasive, efficient diagnostic method for NIID, with rapid healing and excellent sensitivity.

Diagnostic value of nerve conduction study in NOTCH2NLC-related neuronal intranuclear inclusion disease

BACKGROUND AND AIMS

Neuronal intranuclear inclusion disease (NIID) is a rare progressive neurodegenerative disorder mainly caused by abnormally expanded GGC repeats within the NOTCH2NLC gene. Most patients with NIID show polyneuropathy. Here, we aim to investigate diagnostic electrophysiological markers of NIID.

METHODS

In this retrospective dual-center study, we reviewed 96 patients with NOTCH2NLC-related NIID, 94 patients with genetically confirmed Charcot-Marie-Tooth (CMT) disease, and 62 control participants without history of peripheral neuropathy, who underwent nerve conduction studies between 2018 and 2022.

RESULTS

Peripheral nerve symptoms were presented by 53.1% of patients with NIID, whereas 97.9% of them showed peripheral neuropathy according to electrophysiological examinations. Patients with NIID were characterized by slight demyelinating sensorimotor polyneuropathy; some patients also showed mild axonal lesions. Motor nerve conduction velocity (MCV) of the median nerve usually exceeded 35 m/s, and were found to be negatively correlated with the GGC repeat sizes. Regarding the electrophysiological differences between muscle weakness type (n = 27) and non-muscle weakness type (n = 69) of NIID, nerve conduction abnormalities were more severe in the muscle weakness type involving both demyelination and axonal impairment. Notably, specific DWI subcortical lace sign was presented in only 33.3% of muscle weakness type, thus it was difficult to differentiate them from CMT. Combining age of onset, distal motor latency, and compound muscle action potential of the median nerve showed the optimal diagnostic performance to distinguish NIID from major CMT (AUC = 0.989, sensitivity = 92.6%, specificity = 97.4%).

INTERPRETATION

Peripheral polyneuropathy is common in NIID. Our study suggest that nerve conduction study is useful to discriminate NIID.

Skin biopsy and neuronal intranuclear inclusion disease

Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disease with variable clinical phenotypes. There is a considerable delay in the definite diagnosis, which primarily depends on postmortem brain pathological examination. Although CGG repeat expansion in the 5'-untranslated region of NOTCH2NLC has been identified as a disease-associated variant, the pathological diagnosis is still required in certain NIID cases. Intranuclear inclusions found in the skin tissue of patients with NIID dramatically increased its early detection rate. Skin biopsy, as a minimally invasive method, has become widely accepted as a routine examination to confirm the pathogenicity of the repeat expansion in patients with suspected NIID. In addition, the shared developmental origin of the skin and nerve system provided a new insight into the pathological changes observed in patients with NIID. In this review, we systematically discuss the role of skin biopsy for NIID diagnosis, the procedure of skin biopsy, and the pathophysiological mechanism of intranuclear inclusion in the skin.

A comprehensive study of clinicopathological and genetic features of neuronal intranuclear inclusion disease

BACKGROUND

The discovery of skin intranuclear inclusions and GGC repeat expansion of NOTCH2NLC has greatly promoted the diagnosis of neuronal intranuclear inclusion disease (NIID). With highly heterogeneous clinical manifestations, NIID patients tend to be underdiagnosed at early stages.

METHODS

This study comprehensively studied clinical manifestations, magnetic resonance imaging (MRI), and peripheral nerve conduction in 24 NIID and 166 other neurodegenerative disease (ND) subjects. The nomogram was plotted using the "rms" package, and the t-distributed stochastic neighbor embedding algorithm was performed. Associations between skin intranuclear inclusions and NOTCH2NLC GGC repeats were further analyzed.

RESULTS

The clinical, MRI, and peripheral nerve conduction features seriously overlapped in NIID and ND patients; they were assigned variables according to their frequency and specificity in NIID patients. A nomogram that could distinguish NIID from ND was constructed according to the assigned variables and cutoff values of the above features. The occurrence of skin intranuclear inclusions and NOTCH2NLC GGC repeats ≥ 60 showed 100% consistency, and intranuclear inclusion frequency positively correlated with NOTCH2NLC GGC repeats. A hierarchical diagnostic flowchart for definite NIID was further established.

CONCLUSION

We provide a novel nomogram with the potential to realize early identification and update the diagnostic flowchart for definitive diagnosis. Moreover, this is the first study to define the association between skin pathology and NOTCH2NLC genetics in NIID.

MRI features of neuronal intranuclear inclusion disease, combining visual and quantitative imaging investigations

OBJECTIVE

To observe the radiological characteristics of Neuronal Intranuclear Inclusion Disease (NIID) on lesion locations and diffusion property using quantitative imaging analysis.

METHODS

Visual inspection and quantitative analyses were performed on MRI data from 31 retrospectively included patients with NIID. Frequency heatmaps of lesion locations on T2WI and DWI were generated using voxel-wise analysis. Gray matter volume (GMV), white matter volume (WMV) and diffusion property of apparent diffusion coefficient (ADC) values of patients were voxel-wisely compared with healthy controls. Moreover, the ADC values within the DWI-detected lesion were compared with those within the adjacent cortical gray matter and white matter. Voxel-based lesion symptom mapping (VLSM) techniques, were used to determine the relationship between DWI lesion location and disease durations.

RESULTS

By visual inspection on the imaging findings, we proposed an "cockscomb flower sign" for describing the radiological feature of DWI hyperintensity within the corticomedullary junction. A "T2WI-DWI mismatch of spatial distribution" pattern was also revealed with visual inspection and frequency heatmaps, for describing the feature of a wider lesion distribution covering white matter shown on T2WI than that on DWI. Voxel-based morphometry comparison revealed that wildly reduced GMV and WMV, both the lesion areas detected by DWI and T2WI demonstrated ADC increase in patients. Furthermore, the ADC values within the DWI-detected lesion were intermediate between the adjacent cortex and the deep white matter with highest ADC. VLSM analysis revealed that frontal lobe, parietal lobe and internal capsule damage were associated with higher NIID durations.

CONCLUSION

NIID features with "cockscomb flower-like" DWI hyperintensity in area of corticomedullary junction, based on a "T2WI-DWI mismatch of spatial distribution" of lesion locations. The pathological substrate of corticomedullary junction hyperintensity on DWI, can not be explained as diffusion restriction. These typical radiological features of brain MRI would be helpful for diagnosis of NIID.

The clinical characteristics of neuronal intranuclear inclusion disease and its relation with inflammation

BACKGROUND

Neuronal intranuclear inclusion disease (NIID) is a great imitator with a broad spectrum of clinical manifestations that include dementia, parkinsonism, paroxysmal symptoms, peripheral neuropathy, and autonomic dysfunction. Hence, it may also masquerade as other diseases such as Alzheimer's disease, Parkinson's disease, and Charcot-Marie-Tooth disease. Recent breakthroughs on neuroimaging, skin biopsy, and genetic testing have facilitated the diagnosis. However, early identification and effective treatment are still difficult in cases of NIID.

OBJECTIVE

To further study the clinical characteristics of NIID and investigate the relationship between NIID and inflammation.

METHODS

We systematically evaluated the clinical symptoms, signs, MRI and electromyographical findings, and pathological characteristics of 20 NIID patients with abnormal GGC repeats in the NOTCH2NLC gene. Some inflammatory factors in the patients were also studied.

RESULTS

Paroxysmal symptoms such as paroxysmal encephalopathy, stroke-like episodes, and mitochondrial encephalomyopathy lactic acidosis and stroke (MELAS)-like episode were the most common phenotypes. Other symptoms such as cognitive dysfunction, neurogenic bladder, tremor, and vision disorders were also suggestive of NIID. Interestingly, not all patients showed apparent diffusion-weighted imaging (DWI) abnormality or intranuclear inclusions, while abnormal GGC repeats of NOTCH2NLC were seen in all patients. And fevers were noticed in some patients during encephalitic episodes, usually with increasing leukocyte counts and neutrophil ratios. Both IL-6 (p = 0.019) and TNF-α (p = 0.027) levels were significantly higher in the NIID group than in normal controls.

CONCLUSION

Genetic testing of NOTCH2NLC may be the best choice in the diagnosis of NIID. Inflammation might be involved in the pathogenesis of NIID.

Intrafamilial phenotypic heterogeneity in GIPC1-related oculopharyngodistal myopathy type 2: a case report

Oculopharyngodistal myopathy (OPDM) is a rare adult-onset neuromuscular disease characterized by ocular, facial, bulbar and distal limb muscle weakness. Here, we presented a pair of siblings with OPDM2 displaying marked intrafamilial phenotypic heterogeneity. In addition to muscle weakness, the proband also demonstrated tremor and visual disturbance that have not been reported previously in OPDM2. Electrophysiological and pathological studies further suggested the presence of neurogenic impairment in the proband. Repeat-primed polymerase chain reaction (RP-PCR) and fluorescence amplicon length analysis polymerase chain reaction (AL-PCR) confirmed the molecular diagnosis of OPDM2 in the siblings. Given the rarity of the case, the association between OPDM2 and tremor, visual disturbance, or neurogenic impairment remained to be explored.

Expression of expanded GGC repeats within NOTCH2NLC causes cardiac dysfunction in mouse models

BACKGROUND

Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disorder characterized by widespread intranuclear inclusions in the nervous system as well as multiple visceral organs. In 2019, expanded GGC repeats within the 5' untranslated region of the NOTCH2NLC gene was identified as the causative factor. NIID is a heterogeneous disorder with variable clinical manifestations including cognitive impairment, cerebellar ataxia, parkinsonism, paroxysmal symptoms, autonomic dysfunction, and muscle weakness. Although NIID primarily affects the central and peripheral nervous systems, growing evidence suggests potential cardiac abnormalities in NIID. However, the link between expanded GGC repeats within NOTCH2NLC and cardiac dysfunction remains uncertain.

RESULTS

In this study, we utilized two transgenic mouse models, expressing NOTCH2NLC-(GGC)98 ubiquitously or specifically in cardiomyocytes, and identified p62 (also known as sequestosome 1, SQSTM1)-positive intranuclear NOTCH2NLC-polyG inclusions in cardiomyocytes in two mouse models. We observed that both models exhibited cardiac-related pathological and echocardiographic changes, albeit exhibiting varying degrees of severity. Transcriptomic analysis revealed shared downregulation of genes related to ion channels and mitochondria in both models, with the cardiomyocyte-specific mice showing a more pronounced downregulation of mitochondria and energy metabolism-related pathways. Further investigations revealed decreased expression of mitochondria-related genes and electron transport chain activity. At last, we conducted a retrospective review of cardiac-related examination results from NIID patients at our hospital and also identified some cardiac abnormalities in NIID patients.

CONCLUSIONS

Our study provided the first in vivo evidence linking GGC repeat expansions within NOTCH2NLC to cardiac abnormalities and highlighted the contribution of mitochondrial dysfunction in the development of cardiac abnormalities.

Not your usual neurodegenerative disease: a case report of neuronal intranuclear inclusion disease with unconventional imaging patterns

Background

Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative illness with characteristic brain magnetic resonance imaging (MRI) manifestations: diffuse symmetric white-matter hyperintensities in lateral cerebral ventricle areas in fluid-attenuated inversion recovery (FLAIR) and high-intensity signals along the corticomedullary junction of the frontal-parietal-temporal lobes in diffusion weighted imaging (DWI). Here, we report a case of adult-onset NIID who was misdiagnosed with Susac syndrome (SS) due to unusual corpus callosum imaging findings.

Case presentation

A 39-year-old man presented with chronic headache, blurred vision, tinnitus, and numbness in the hands as initial symptoms, accompanied by cognitive slowing and decreased memory. Brain MRI revealed round hypointense lesions on T1-weighted imaging (T1WI) and hyperintense lesions on T2WI/FLAIR/DWI in the genu and splenium of the corpus callosum. An initial diagnosis of SS was made based on the presence of the SS-typical symptoms and SS-characteristic radiology changes. Furthermore, the patient's symptoms improved upon completion of a combined pharmacotherapy plan. However, no significant changes were evident 18 months after the brain MRI scan. Eventually, the patient was then diagnosed with NIID based on a skin biopsy and detection of expanded GGC (guanine, guanine, cytosine) repeats in the NOTCH2NLC gene.

Conclusion

The present NIID case in which there was simultaneous onset of altered nervous and visual system functioning and atypical imaging findings, the atypical imaging findings may reflect an initial change of NIID leukoencephalopathy.

Clinical phenotypic diversity of NOTCH2NLC-related disease in the largest case series of inherited peripheral neuropathy in Japan

BACKGROUND

NOTCH2NLC GGC repeat expansions have been associated with various neurogenerative disorders, including neuronal intranuclear inclusion disease and inherited peripheral neuropathies (IPNs). However, only a few NOTCH2NLC-related disease studies in IPN have been reported, and the clinical and genetic spectra remain unclear. Thus, this study aimed to describe the clinical and genetic manifestations of NOTCH2NLC-related IPNs.

METHOD

Among 2692 Japanese patients clinically diagnosed with IPN/Charcot-Marie-Tooth disease (CMT), we analysed NOTCH2NLC repeat expansion in 1783 unrelated patients without a genetic diagnosis. Screening and repeat size determination of NOTCH2NLC repeat expansion were performed using repeat-primed PCR and fluorescence amplicon length analysis-PCR.

RESULTS

NOTCH2NLC repeat expansions were identified in 26 cases of IPN/CMT from 22 unrelated families. The mean median motor nerve conduction velocity was 41 m/s (range, 30.8-59.4), and 18 cases (69%) were classified as intermediate CMT. The mean age of onset was 32.7 (range, 7-61) years. In addition to motor sensory neuropathy symptoms, dysautonomia and involuntary movements were common (44% and 29%). Furthermore, the correlation between the age of onset or clinical symptoms and the repeat size remains unclear.

CONCLUSIONS

These findings of this study help us understand the clinical heterogeneity of NOTCH2NLC-related disease, such as non-length-dependent motor dominant phenotype and prominent autonomic involvement. This study also emphasise the importance of genetic screening, regardless of the age of onset and type of CMT, particularly in patients of Asian origin, presenting with intermediate conduction velocities and dysautonomia.

A case of unusual renal manifestation in a patient with neuronal intranuclear inclusion disease treated with steroids

Neuronal intranuclear inclusion disease (NIID) is a progressive neurodegenerative disorder characterized by intranuclear inclusions. Kidney injury involvement and successful treatment for NIID have rarely been reported. A NIID patient developed crescentic IgA nephropathy. Steroid therapy resolved digestive symptoms and recovered renal function. Steroids are considered for concomitant symptoms of NIID.

Adult-onset leukodystrophies: a practical guide, recent treatment updates, and future directions

Adult-onset leukodystrophies though individually rare are not uncommon. This group includes several disorders with isolated adult presentations, as well as several childhood leukodystrophies with attenuated phenotypes that present at a later age. Misdiagnoses often occur due to the clinical and radiological overlap with common acquired disorders such as infectious, immune, inflammatory, vascular, metabolic, and toxic etiologies. Increased prevalence of non-specific white matter changes in adult population poses challenges during diagnostic considerations. Clinico-radiological spectrum and molecular landscape of adult-onset leukodystrophies have not been completely elucidated at this time. Diagnostic approach is less well-standardized when compared to the childhood counterpart. Absence of family history and reduced penetrance in certain disorders frequently create a dilemma. Comprehensive evaluation and molecular confirmation when available helps in prognostication, early initiation of treatment in certain disorders, enrollment in clinical trials, and provides valuable information for the family for reproductive counseling. In this review article, we aimed to formulate an approach to adult-onset leukodystrophies that will be useful in routine practice, discuss common adult-onset leukodystrophies with usual and unusual presentations, neuroimaging findings, recent advances in treatment, acquired mimics, and provide an algorithm for comprehensive clinical, radiological, and genetic evaluation that will facilitate early diagnosis and consider active treatment options when available. A high index of suspicion, awareness of the clinico-radiological presentations, and comprehensive genetic evaluation are paramount because treatment options are available for several disorders when diagnosed early in the disease course.

Longitudinal course of hyperintensity on diffusion weighted imaging in adult-onset neuronal intranuclear inclusion disease patients

Background

High signals on diffusion weighted imaging along the corticomedullary junction (CMJ) have demonstrated excellent diagnostic values for adult-onset neuronal intranuclear inclusion disease (NIID). However, the longitudinal course of diffusion weighted imaging high intensities in adult-onset NIID patients has rarely been investigated.

Methods

We described four NIID cases that had been discovered using skin biopsy and NOTCH2NLC gene testing, after diffusion weighted imaging exhibiting the distinctive corticomedullary junction high signals. Then using complete MRI data from NIID patients, we analyzed the chronological diffusion weighted imaging alterations of those individuals that had been published in Pub Med.

Results

We discussed 135 NIID cases with comprehensive MRI data, including our four cases, of whom 39 had follow-up outcomes. The following are the four primary diffusion weighted imaging dynamic change patterns: (1) high signal intensities in the corticomedullary junction were negative on diffusion weighted imaging even after an 11-year follow-up (7/39); (2) diffusion weighted imagings were initially negative but subsequently revealed typical findings (9/39); (3) high signal intensities vanished during follow-up (3/39); (4) diffusion weighted imagings were positive at first and developed in a step-by-step manner (20/39). We discovered that NIID lesions eventually damaged the deep white matter, which comprises the cerebral peduncles, brain stem, middle cerebellar peduncles, paravermal regions, and cerebellar white matter.

Conclusion

The longitudinal dynamic changes in NIID of diffusion weighted imaging are highly complex. We find that there are four main patterns of dynamic changes on diffusion weighted imaging. Furthermore, as the disease progressed, NIID lesions eventually involved the deep white matter.

Heterogenous Genetic, Clinical, and Imaging Features in Patients with Neuronal Intranuclear Inclusion Disease Carrying NOTCH2NLC Repeat Expansion

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disorder that is caused by the abnormal expansion of non-coding trinucleotide GGC repeats in NOTCH2NLC. NIID is clinically characterized by a broad spectrum of clinical presentations. To date, the relationship between expanded repeat lengths and clinical phenotype in patients with NIID remains unclear. Thus, we aimed to clarify the genetic and clinical spectrum and their association in patients with NIID. For this purpose, we genetically analyzed Japanese patients with adult-onset NIID with characteristic clinical and neuroimaging findings. Trinucleotide repeat expansions of NOTCH2NLC were examined by repeat-primed and amplicon-length PCR. In addition, long-read sequencing was performed to determine repeat size and sequence. The expanded GGC repeats ranging from 94 to 361 in NOTCH2NLC were found in all 15 patients. Two patients carried biallelic repeat expansions. There were marked heterogenous clinical and imaging features in NIID patients. Patients presenting with cerebellar ataxia or urinary dysfunction had a significantly larger GGC repeat size than those without. This significant association disappeared when these parameters were compared with the total trinucleotide repeat number. ARWMC score was significantly higher in patients who had a non-glycine-type trinucleotide interruption within expanded poly-glycine motifs than in those with a pure poly-glycine expansion. These results suggested that the repeat length and sequence in NOTCH2NLC may partly modify some clinical and imaging features of NIID.

Characteristics of autonomic dysfunction in neuronal intranuclear inclusion disease

Background

This study aimed to investigate the features of autonomic dysfunction (AutD) in a large cohort of patients with neuronal intranuclear inclusion disease (NIID).

Methods

A total of 122 patients with NIID and 122 controls were enrolled. All participants completed the Scales for Outcomes in Parkinson's Disease-Autonomic Questionnaire (SCOPA-AUT) and genetic screening for GGC expanded repeats within the NOTCH2NLC gene. All patients underwent neuropsychological and clinical assessments. SCOPA-AUT was performed to compare AutD between patients and controls. The associations between AutD and disease-related characteristics of NIID were studied.

Results

94.26% of patients had AutD. Compared with controls, patients had more severe AutD in total SCOPA-AUT, gastrointestinal, urinary, cardiovascular, thermoregulatory, pupillomotor and sexual domains (all p < 0.05). The area under the curve (AUC) value for the total SCOPA-AUT (AUC = 0.846, sensitivity = 69.7%, specificity = 85.2%, cutoff value = 4.5) was high in differentiating AtuD of patients with NIID from controls. The total SCOPA-AUT was significantly and positively associated with age (r = 0.185, p = 0.041), disease duration (r = 0.207, p = 0.022), Neuropsychiatric Inventory (NPI) (r = 0.446, p < 0.01), and Activities of Daily Living (ADL) (r = 0.390, p < 0.01). Patients with onset-of-AutD had higher SCOPA-AUT scores than patients without onset-of-AutD (p < 0.001), especially in the urinary system (p < 0.001) and male sexual dysfunction (p < 0.05).

Conclusion

SCOPA-AUT can be used as a diagnostic and quantitative tool for autonomic dysfunction in NIID. The high prevalence of AutD in patients suggests that NIID diagnosis should be considered in patients with AutD, especially in those with unexplained AutD alone. AutD in patients is related to age, disease duration, impairment of daily living ability, and psychiatric symptoms.