Interrelated Pathogenesis? Neuronal Intranuclear Inclusion Disease Combining With Hemiplegic Migraine

Clinical and multimodal imaging features of adult-onset neuronal intranuclear inclusion disease

OBJECTIVES

This study aimed to analyze the clinical and multimodal imaging manifestations of adult-onset neuronal intranuclear inclusion disease (NIID) patients and to investigate NIID-specific neuroimaging biomarkers.

METHODS

Forty patients were retrospectively enrolled from the Qilu Hospital of Shandong University. We analyzed the clinical and imaging characteristics of 40 adult-onset NIID patients and investigated the correlation between these characteristics and genetic markers and neuropsychological scores. We further explored NIID-specific alterations using multimodal imaging indices, including diffusion tensor imaging (DTI), magnetic resonance spectroscopy (MRS), and brain age estimation. In addition, we summarized the dynamic evolution pattern of NIID by examining the changes in diffusion weighted imaging (DWI) signals over time.

RESULTS

The NIID patients' ages ranged from 31 to 77 years. Cognitive impairment was the most common symptom (30/40, 75.0%), while some patients (18/40, 45.0%) initially presented with episodic symptoms such as headache (10/40, 25.0%). Patients with cognitive impairment symptoms had more cerebral white matter damage (χ2 = 11.475, P = 0.009). The most prevalent imaging manifestation was a high signal on DWI in the corticomedullary junction area, which was observed in 80.0% (32/40) of patients. In addition, the DWI dynamic evolution patterns could be classified into four main patterns. Diffusion tensor imaging (DTI) revealed extensive thinning of cerebral white matter fibers. The estimated brain age surpassed the patient's chronological age, signifying advanced brain aging in NIID patients.

CONCLUSIONS

The clinical manifestations of NIID exhibit significant variability, usually leading to misdiagnosis. Our results provided new imaging perspectives for accurately diagnosing and exploring this disease's neuropathological mechanisms.

Familial adult-onset neuronal intranuclear inclusion disease: A case report and literature review

RATIONALE

Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disorder with highly variable clinical manifestations, making diagnosis challenging. Recent advancements in genetic and pathological testing, such as the identification of GGC repeat expansions in the NOTCH2NLC gene, have improved diagnostic accuracy, but familial cases remain underreported.

PATIENT CONCERNS

This report details 3 cases of familial adult-onset NIID in 2 sisters and 1 brother. The older sister experienced episodic encephalopathy and autonomic dysfunction for over 40 years, while the younger sister presented similar symptoms 5 years ago. The brother also developed episodic encephalopathy 5 years ago. Brain diffusion-weighted imaging (DWI) for all 3 patients revealed hyperintensity at the corticomedullary junction and corpus callosum. Skin biopsies from the older sister and brother confirmed the presence of p62 antibody-positive intranuclear inclusion bodies in sweat gland cells and fibroblasts. Genetic testing showed 146 and 133 GGC repeats in the NOTCH2NLC gene in the older sister and brother, respectively.

DIAGNOSES

All 3 patients were diagnosed with NIID based on clinical, radiological, and genetic findings.

INTERVENTIONS

The patients received hormonal therapy, circulation-enhancing treatments, and rehydration therapy during acute episodes.

OUTCOMES

All 3 patients showed significant improvement in symptoms following treatment, with a return to baseline function after hospital discharge.

LESSONS

Proper management of NIID includes prompt recognition of symptoms, adequate rest, and avoidance of triggers such as fatigue, infections, and stress, which may reduce the frequency of episodic attacks. Early diagnosis and targeted symptomatic treatment are essential for improving patient outcomes.

A Case Report of Hemiplegic Migraine with Mutation in the ATP1A2 Gene

Background

Hemiplegic migraine, a less common variant of migraine, is the focus of this paper. Within the scope of this study, we present a case of hemiplegic migraine that bears the potential for misdiagnosis, particularly as encephalitis.

Brief introduction to the Disease

The patient developed a right-sided headache a day prior to admission, accompanied by fever, nausea, vomiting, and left-sided limb weakness. On the fourth day, the patient experienced a grand mal epilepsy, marked by unconsciousness, leftward deviation of both eyes, limb convulsions, and foaming at the mouth. Cerebrospinal fluid analysis revealed no apparent abnormalities, Electroencephalography showed abnormal slow waves, imaging studies indicated swelling and meningeal thickening in the right cortex, and genetic testing identified a heterozygous mutation in the ATPIA2 gene. The diagnosis was hemiplegic migraine, and the patient received symptomatic supportive treatment, leading to improvement and subsequent discharge. Flunarizine and sodium valproate were prescribed post-discharge, and the patient achieved complete recovery after a one-month follow-up.

Conclusion

Apart from experiencing headaches, patients with hemiplegic migraine may exhibit additional symptoms like fever, epilepsy, and hemiplegia. These manifestations warrant clinical attention, and if deemed necessary, genetic testing should be conducted, and this is an autosomal dominant pattern.

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.

Photobiomodulation of Neurogenesis through the Enhancement of Stem Cell and Neural Progenitor Differentiation in the Central and Peripheral Nervous Systems

Photobiomodulation (PBM) is the regulation of biological processes using light energy from sources such as lasers or light-emitting diodes. Components of the nervous system, such as the brain and peripheral nerves, are important candidate PBM targets due to the lack of therapeutic modalities for the complete cure of neurological diseases. PBM can be applied either to regenerate damaged organs or to prevent or reduce damage caused by disease. Although recent findings have suggested that neural cells can be regenerated, which contradicts our previous understanding, neural structures are still thought to have weaker regenerative capacity than other systems. Therefore, enhancing the regenerative capacity of the nervous system would aid the future development of therapeutics for neural degeneration. PBM has been shown to enhance cell differentiation from stem or progenitor cells to near-target or target cells. In this review, we have reviewed research on the effects of PBM on neurogenesis in the central nervous system (e.g., animal brains) and the peripheral nervous system (e.g., peripheral sensory neural structures) and sought its potential as a therapeutic tool for intractable neural degenerative disorders.

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.

Hemiplegic Migraine

PURPOSE OF REVIEW

In this article, we review recent updates to the epidemiology, diagnostic testing, genetics, pathophysiology, and management of hemiplegic migraine.

RECENT FINDINGS

While three genes have been historically associated with hemiplegic migraine, recent studies suggest two additional genes may also be implicated including PPRT2 and SLC1A3. Hemiplegic migraine is a severe subset of migraine with aura with symptoms including reversible hemiparesis in addition to other aura symptoms such as visual, sensory, or speech. The exact pathophysiology of hemiplegic migraine is not clear, but it is thought that this phenomenon is due to neuronal and glial depolarization causing cortical spreading depression. Due to the severity of presentation as well as the numerous mimickers, it is important to know a comprehensive differential and work-up. Given the low prevalence of the disease, most studies regarding treatment are limited to case studies. There is still an important need for further and larger studies regarding management of these cases.

Clinical Features and Classification of Neuronal Intranuclear Inclusion Disease

Background and Objectives

Neuronal intranuclear inclusion body disease (NIID) is a neurodegenerative disease with highly heterogeneous clinical manifestations. The present study aimed to characterize clinical features and propose a classification system based on a large cohort of NIID in China.

Methods

The Chinese NIID registry was launched from 2017, and participants' demographics and clinical features were recorded. Brain MRI, skin pathologies, and the number of GGC repeat expansions in the 5′ untranslated region of theNOTCH2NLCgene were evaluated in all patients.

Results

In total, 223 patients (64.6% female) were recruited; the mean (SD) onset age was 56.7 (10.3) years. The most common manifestations were cognitive impairment (78.5%) and autonomic dysfunction (70.9%), followed by episodic symptoms (51.1%), movement disorders (50.7%), and muscle weakness (25.6%). Imaging markers included hyperintensity signals along the corticomedullary junction on diffusion-weighted imaging (96.6%), white matter lesions (98.1%), paravermis (55.0%), and focal cortical lesions (10.1%). The median size of the expanded GGC repeats in these patients was 115 (range, 70–525), with 2 patients carrying >300 GGC repeats. A larger number of GGC repeats was associated with younger age at onset (r= −0.329,p< 0.0001). According to the proposed clinical classification based on the most prominent manifestations, the patients were designated into 5 distinct types: cognitive impairment-dominant type (34.1%, n = 76), episodic neurogenic event-dominant type (32.3%, n = 72), movement disorder-dominant type (17.5%, n = 39), autonomic dysfunction-dominant type (8.5%, n = 19), and neuromuscular disease-dominant type (7.6%, n = 17). Notably, 32.3% of the episodic neurogenic event-dominant type of NIID has characteristic focal cortical lesions on brain MRI presenting localized cortical edema or atrophy. The mean onset age of the neuromuscular disease-dominant type was 47.2 (17.6) years, younger than the other types (p< 0.001). There was no significant difference in the sizes of GGC repeats among the patients in the 5 types (p= 0.547, Kruskal-Wallis test).

Discussion

This observational study of NIID establishes an overall picture of the disease regarding clinical, imaging, and genetic characteristics. The proposed clinical classification of NIID based on the most prominent manifestation divides patients into 5 types.

Characteristic cerebral perfusion pattern in neuronal intranuclear inclusion disease

Background

Neuronal intranuclear inclusion disease (NIID), which pathogenesis remains largely unclear, is a neurodegenerative disease caused by GGC repeat expansion in NOTCH2NLC gene. As case studies have reported dynamic cortical perfusion changes in NIID, this study aimed to explore the cerebral perfusion pattern in NIID patients.

Materials and methods

A total of 38 NIID patients and 34 healthy controls (HCs) were recruited, and 2 NIID patients who had had episodic symptoms within 2 months were excluded. Data on demographic characteristics and clinical features were collected. All participants underwent three-dimensional pseudo-continuous arterial spin labeling perfusion magnetic resonance imaging (MRI) scanning. Voxel-based comparisons of cerebral blood flow (CBF) were conducted.

Results

NIID patients showed decreased perfusion in the cortex but increased perfusion in the deep brain regions compared with HCs. The regions with significant hypoperfusion were distributed in the bilateral frontal, temporal, parietal, and occipital gyri, with the left frontal gyrus being the most prominent. The regions with significant hyperperfusion included the bilateral basal ganglia, midbrain, pons, para-hippocampal, and parts of the bilateral cerebellum, fusiform, lingual, rectus, orbital, and cingulum anterior gyri, which were adjacent to the midline (all FDR-corrected p <0.05). When comparing the mean CBF value of the whole brain, no significant differences were observed between NIID patients and HCs (28.81 ± 10.1 vs. 27.99 ± 5.68 ml/100 g*min, p = 0.666). Voxel-based analysis showed no significant difference in cerebral perfusion between NIID patients with and without episodic symptoms. The perfusion within the bilateral middle frontal and anterior cingulate gyri showed positive correlations with MMSE and MoCA scores using age, sex, and education as covariates (p <0.005 uncorrected).

Conclusion

NIID patients exhibited characteristic cortical hypoperfusion and deep brain hyperperfusion. The perfusion in the bilateral frontal lobe and cingulate gyrus was correlated with the severity of cognitive dysfunction. Cerebral perfusion change may be involved in NIID pathophysiology and serve as a potential indicator for monitoring NIID severity and progression.

Clinical features of NOTCH2NLC-related neuronal intranuclear inclusion disease

BACKGROUND

Abnormal expanded GGC repeats within the NOTCH2HLC gene has been confirmed as the genetic mechanism for most Asian patients with neuronal intranuclear inclusion disease (NIID). This cross-sectional observational study aimed to characterise the clinical features of NOTCH2NLC-related NIID in China.

METHODS

Patients with NOTCH2NLC-related NIID underwent an evaluation of clinical symptoms, a neuropsychological assessment, electrophysiological examination, MRI and skin biopsy.

RESULTS

In the 247 patients with NOTCH2NLC-related NIID, 149 cases were sporadic, while 98 had a positive family history. The most common manifestations were paroxysmal symptoms (66.8%), autonomic dysfunction (64.0%), movement disorders (50.2%), cognitive impairment (49.4%) and muscle weakness (30.8%). Based on the initial presentation and main symptomology, NIID was divided into four subgroups: dementia dominant (n=94), movement disorder dominant (n=63), paroxysmal symptom dominant (n=61) and muscle weakness dominant (n=29). Clinical (42.7%) and subclinical (49.1%) peripheral neuropathies were common in all types. Typical diffusion-weighted imaging subcortical lace signs were more frequent in patients with dementia (93.9%) and paroxysmal symptoms types (94.9%) than in those with muscle weakness (50.0%) and movement disorders types (86.4%). GGC repeat sizes were negatively correlated with age of onset (r=-0.196, p<0.05), and in the muscle weakness-dominant type (median 155.00), the number of repeats was much higher than in the other three groups (p<0.05). In NIID pedigrees, significant genetic anticipation was observed (p<0.05) without repeat instability (p=0.454) during transmission.

CONCLUSIONS

NIID is not rare; however, it is usually misdiagnosed as other diseases. Our results help to extend the known clinical spectrum of NOTCH2NLC-related NIID.

Recurrent headache and visual symptoms in a young man: a rare neuronal intranuclear inclusion disease case report

Background

Neuronal intranuclear inclusion disease (NIID) is a progressive neurodegenerative disease. Patients with NIID may present with heterogeneous clinical symptoms, including episodic encephalopathy, dementia, limb weakness, cerebellar ataxia, and autonomic dysfunction. Among the NIID cases reported in China, patients often have complicated and severe manifestations. Therefore, many clinicians do not consider the disease when the patient presents with relatively minor complaints.

Case presentation

We present the case of a 39-year-old man showing migraine-aura-like symptoms for the past 3 years. Brain magnetic resonance imaging (MRI) revealed hyperintense signals in the splenium of the corpus callosum and corticomedullary junction on diffusion-weighted imaging (DWI) over time. In addition, brain atrophy that was not concomitant with the patient’s age was detected while retrospectively reviewing the patient’s imaging results. Genetic analysis and skin biopsy confirmed a diagnosis of NIID. The patient was treated with sibelium, and the symptoms did not recur.

Discussion and Conclusions

Migraine-aura-like symptoms may be the predominant clinical presentation in young patients with NIID. Persistent high-intensity signals on DWI in the brain and early-onset brain atrophy might be clues for the diagnosis of NIID.

Clinical and mechanism advances of neuronal intranuclear inclusion disease

Due to the high clinical heterogeneity of neuronal intranuclear inclusion disease (NIID), it is easy to misdiagnose this condition and is considered to be a rare progressive neurodegenerative disease. More evidence demonstrates that NIID involves not only the central nervous system but also multiple systems of the body and shows a variety of symptoms, which makes a clinical diagnosis of NIID more difficult. This review summarizes the clinical symptoms in different systems and demonstrates that NIID is a multiple-system intranuclear inclusion disease. In addition, the core triad symptoms in the central nervous system, such as dementia, parkinsonism, and psychiatric symptoms, are proposed as an important clue for the clinical diagnosis of NIID. Recent studies have demonstrated that expanded GGC repeats in the 5′-untranslated region of the NOTCH2NLC gene are the cause of NIID. The genetic advances and possible underlying mechanisms of NIID (expanded GGC repeat-induced DNA damage, RNA toxicity, and polyglycine-NOTCH2NLC protein toxicity) are briefly summarized in this review. Interestingly, inflammatory cell infiltration and inflammation were observed in the affected tissues of patients with NIID. As a downstream pathological process of NIID, inflammation could be a therapeutic target for NIID.

A Case Report of Neuronal Intranuclear Inclusion Disease Presenting With Recurrent Migraine-Like Attacks and Cerebral Edema: A Mimicker of MELAS

Background

Neuronal intranuclear inclusion disease (NIID) is a progressive neurodegenerative disease associated with the GGC repeats in the 5'-untranslated region (5'UTR) of NOTCH2NLC. NIID exhibits a wide range of clinical manifestations. However, patients presenting with recurrent migraine-like attacks and cerebral edema have only rarely been reported.

Case Presentation

A Chinese female suffered probable migraines with aura for 10 years. At age of 51, aggravating migraine-like attacks co-occurred with a sudden encephalopathy-like episode. Brain MRI showed right cerebral edema and cortical enhancement. Serum lactic acid level was elevated at rest and significantly increased after a simplified serum lactic acid exercise test. The initial diagnosis was MELAS, while NIID was suspected after faint DWI high-intensity signals in the corticomedullary junction was retrospectively recognized. Mitochondrial genome sequencing and gene panel analysis of nuclear genes related to mitochondrial diseases failed to find any causative variants. Repeat-primed PCR and fluorescence amplicon length PCR of NOTCH2NLC gene identified an abnormal expansion of 118 GGC repeats in the 5'UTR of NOTCH2NLC gene.

Conclusion

NIID should be taken into account for differential diagnosis of migraines and MELAS-like episodes. Besides the corticomedullary hyperintensity on DWI, cortical enhancement in contrast-enhanced brain MRI may also be a brain image marker for the differential diagnosis between MELAS and NIID with MELAS-like episodes.

Neuronal intranuclear inclusion disease presented with recurrent vestibular migraine-like attack: a case presentation

Background

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disorder characterized by dementia, tremor, episodic encephalopathy and autonomic nervous dysfunction. To date, vestibular migraine (VM)-like attack has never been reported in cases with NIID. Here, we describe an 86-year-old patient with NIID who presented with recurrent vertigo associated with headache for more than 30 years.

Case presentation

An 86-year-old Chinese woman with vertigo, headache, weakness of limbs, fever, and disturbance of consciousness was admitted to our hospital. She had suffered from recurrent vertigo associated with headache since her 50 s,followed by essential tremor and dementia. On this admission, brain magnetic resonance imaging revealed high intensity signals along the corticomedullary junction on diffusion weighted imaging (DWI). Peripheral neuropathy of the extremities was detected through electrophysiological studies. We diagnosed NIID after detecting eosinophilic intranuclear inclusions in the ductal epithelial cells of sweat glands and identifying an abnormal expansion of 81 GGC repeats in the 5’UTR of NOTCH2NLC gene.

Conclusions

VM-like attack may be associated with NIID.

The Value of NOTCH2NLC Gene Detection and Skin Biopsy in the Diagnosis of Neuronal Intranuclear Inclusion Disease

The clinical manifestations of neuronal intranuclear inclusion disease (NIID) are heterogeneous, and the premortem diagnosis is mainly based on skin biopsy findings. Abnormal GGC repeat expansions in NOTCH2NLC was recently identified in familial and sporadic NIID. The comparison of diagnostic value between abnormal GGC repeat expansions of NOTCH2NLC and skin biopsy has not been conducted yet. In this study, skin biopsy was performed in 10 suspected adult NIID patients with clinical and imaging manifestations, and GGC repeat size in NOTCH2NLC was also screened by repeat primed-PCR and GC-rich PCR. We found that five cases had ubiquitin-immunolabelling intranuclear inclusion bodies by skin biopsy, and all of them were identified with abnormal GGC repeat expansions in NOTCH2NLC, among whom four patients showed typical linear hyperintensity at corticomedullary junction on DWI. Five (5/10) NIID patients were diagnosed by combination of NOTCH2NLC gene detection, skin biopsy or combination of NOTCH2NLC, and typical MRI findings. The diagnostic performance of NOTCH2NLC gene detection was highly consistent with that of skin biopsy (Kappa = 1). The unexplained headache was firstly reported as a new early phenotype of NIID. These findings indicate that NOTCH2NLC gene detection is needed to be a supplement in the diagnose flow of NIID and also may be used as an alternative method to skin biopsy especially in Asian population.

Genetic origin of sporadic cases and RNA toxicity in neuronal intranuclear inclusion disease

BACKGROUND

GGC repeat expansion in NOTCH2NLC has been recently linked to neuronal intranuclear inclusion disease (NIID) via unknown disease mechanisms. Herein, we explore the genetic origin of the sporadic cases and toxic RNA gain-of-function mechanism in NIID.

METHODS

Multiple genetic screenings were performed on NIID individuals and their available family members. Methylation status of blood DNA, NOTCH2NLC mRNA level from muscle biopsies and RNA foci from skin biopsies of NIID individuals or asymptomatic carriers were evaluated and compared.

RESULTS

In two sporadic NIID families, we identified two clinically and pathologically asymptomatic fathers carrying large GGC repeat expansion, above 300 repeats, with offspring repeat numbers of 172 and 148, respectively. Further evaluation revealed that the GGC repeat numbers in the sperm from two asymptomatic fathers were only 63 and 98, respectively. The CpG island in NOTCH2NLC of the asymptomatic carriers was hypermethylated, and accordingly, the NOTCH2NLC mRNA levels were decreased in the asymptomatic fathers. GGC repeat expansion RNA formed RNA foci and sequestered RNA binding proteins into p62 positive intranuclear inclusions in NIID individuals but not in the control or asymptomatic carrier.

CONCLUSION

Our study suggested the GGC repeat expansion in NOTCH2NLC might have a disease-causing number ranging from ~41 to ~300 repeats. The contraction of GGC repeat expansion in sperm could be a possible mechanism for the paternal-biased origin in some sporadic or recessive inherited NIID individuals. The toxic RNA gain-of-function mechanism was identified to be involved in the pathogenicity of this disease.

Neuronal intranuclear inclusion disease: recognition and update

Neuronal intranuclear inclusion disease (NIID) used to be considered as a neurodegenerative disease. Due to the availability of skin biopsy, the diagnostic efficiency of the disease has been greatly improved. Recently, researchers have successfully identified that the GGC repeat expansion in the 5'-untranslated region of the NOTCH2NLC gene is the causative mutation of NIID. Besides the typical phenotype of brain degeneration, peripheral neuropathy, and autonomic disturbance, the gene mutation is also associated with Alzheimer's disease, frontotemporal dementia, Parkinson's disease, multiple system atrophy, essential tremor, adult leukoencephalopathy, and oculopharyngodistal myopathy. However, it still needs more studies to elucidate whether those variable NIID phenotypes can categorize into NOTCH2NLC repeat expansion related disorders. We update the discovery milestone, clinical phenotype, laboratory examinations, as well as new insight into the diagnosis and treatment of NIID. NIID is an unusual degenerative disease that can involve multiple systems, especially involves the nervous system. Originally, it is named after the pathological characteristics with extensive intranuclear eosinophilic inclusions in central and peripheral nervous tissues, as well as in multiple other organs (Sone et al., Brain 139:3170-3186, 2016). In 2019, several research teams from China and Japan have simultaneously identified that the GGC repeat expansion in the 5'-untranslated region (5'UTR) of the NOTCH2NLC gene is the pathogenic mutation of NIID (Ishiura et al., Nat Genet 51:1222-1232, 2019; Deng et al., J Med Genet 56:758-764, 2019; Sone et al., Nat Genet 51:1215-1221, 2019; Sun et al., Brain 143:222-233, 2020; Tian et al., Am J Hum Genet 105:166-176, 2019). Since then, the number of reported NIID cases is rapidly increasing, and the spectrum of NOTCH2NLC repeat expansion related disorders is significantly broadening (Westenberger and Klein, Brain 143:5-8, 2020). However, the NIID associated with GGC repeat expansion of the NOTCH2NLC gene might be account for a part of patients, probably more frequently in the Asian population, because this expansion has not been identified in an European series with postmortem confirmed NIID cases (Chen et al., Ann Clin Transl Neurol 2020). In order to better understand of the disease, we need to revisit the current state of NIID in combination with the findings based on our experiences in recent years and update the concepts about the clinical and pathogenic progression of NIID.

Clinical and pathological features in adult-onset NIID patients with cortical enhancement

BACKGROUND

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disease characterized by eosinophilic hyaline intranuclear inclusions in multiple organs. On conventional MRI, high signals on diffused weight image (DWI) along the corticomedullary junction have demonstrated great diagnostic values for adult-onset NIID. However, changes of contrast MRI in the acute period of the encephalopathy-like episode have rarely been investigated.

METHODS

Patients with enhanced lesions were retrieved in our database including 35 patients with adult-onset NIID between October 2017 and December 2019. Conventional and contrast MRI were conducted in all patients. Standard procedures of skin biopsy were performed in all patients. Repeat-primed PCR and amplicon length PCR were used to screen the GGC expansion in the 5'UTR of the NOTCH2NLC gene.

RESULTS

Four of 35 patients (11.4%) were identified to have a cortical enhancement in this study. The enhanced lesions were selectively spread along the surface of posterior cortex and were clinically associated with encephalopathy-like episodes. These patients had a younger age of onset, shorter duration of disease, and a higher incidence of a headache than those without enhancement. Typical p62-postive intranuclear inclusions were observed in all patients, while patient 1 simultaneously had many nuclei full of abnormal substance immunopositive to p62, as well as short-curly filament materials on electron microscopy. All patients were identified to have GGC repeat expansion in the NOTCH2NLC gene.

CONCLUSION

Post-contrast MRI should be routinely performed in the adult-onset NIID patients. Some patients with adult-onset NIID showed cortical enhancement and edema along the surface of posterior cortex, indicating that dehydrate and anti-inflammatory drugs might be potential therapies for these patients.