Adult-onset neuronal intranuclear inclusion disease presenting with typical MRI changes

NOTCH2NLC GGC intermediate repeat with serine induces hypermyelination and early Parkinson's disease-like phenotypes in mice

BACKGROUND

The expansion of GGC repeats (typically exceeding 60 repeats) in the 5' untranslated region (UTR) of the NOTCH2NLC gene (N2C) is linked to N2C-related repeat expansion disorders (NREDs), such as neuronal intranuclear inclusion disease (NIID), frontotemporal dementia (FTD), essential tremor (ET), and Parkinson's disease (PD). These disorders share common clinical manifestations, including parkinsonism, dementia, seizures, and muscle weakness. Intermediate repeat sizes ranging from 40 to 60 GGC repeats, particularly those with AGC-encoded serine insertions, have been reported to be associated with PD; however, the functional implications of these intermediate repeats with serine insertion remain unexplored.

METHODS

Here, we utilized cellular models harbouring different sizes of N2C variant 2 (N2C2) GGC repeat expansion and CRISPR-Cas9 engineered transgenic mouse models carrying N2C2 GGC intermediate repeats with and without serine insertion to elucidate the underlying pathophysiology associated with N2C intermediate repeat with serine insertion in NREDs.

RESULTS

Our findings revealed that the N2C2 GGC intermediate repeat with serine insertion (32G13S) led to mitochondrial dysfunction and cell death in vitro. The neurotoxicity was influenced by the length of the repeat and was exacerbated by the presence of the serine insertion. In 12-month-old transgenic mice, 32G13S intensified intranuclear aggregation and exhibited early PD-like characteristics, including the formation of α-synuclein fibers in the midbrain and the loss of tyrosine hydroxylase (TH)-positive neurons in both the cortex and striatum. Additionally, 32G13S induced neuronal hyperexcitability and caused locomotor behavioural impairments. Transcriptomic analysis of the mouse cortex indicated dysregulation in calcium signaling and MAPK signaling pathways, both of which are critical for mitochondrial function. Notably, genes associated with myelin sheath components, including MBP and MOG, were dysregulated in the 32G13S mouse. Further investigations using immunostaining and transmission electron microscopy revealed that the N2C intermediate repeat with serine induced mitochondrial dysfunction-related hypermyelination in the cortex.

CONCLUSIONS

Our in vitro and in vivo investigations provide the first evidence that the N2C-GGC intermediate repeat with serine promotes intranuclear aggregation of N2C, leading to mitochondrial dysfunction-associated hypermyelination and neuronal hyperexcitability. These changes contribute to motor deficits in early PD-like neurodegeneration in NREDs.

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.

Nerve conduction features may serve as a diagnostic clue for neuronal intranuclear inclusion disease

Neuronal intranuclear inclusion disease is a neurodegenerative disorder with a wide phenotypic spectrum, including peripheral neuropathy. This study aims to characterize the nerve conduction features and proposes an electrophysiological criterion to assist the diagnosis of neuronal intranuclear inclusion disease. In this study, nerve conduction studies were performed in 50 genetically confirmed neuronal intranuclear inclusion disease patients, 200 age- and sex-matched healthy controls and 40 patients with genetically unsolved leukoencephalopathy. Abnormal electrophysiological parameters were defined as mean values plus or minus two standardized deviations of the healthy controls or failure to evoke a response on the examined nerves. Compared to controls, neuronal intranuclear inclusion disease patients had significantly slower motor and sensory nerve conduction velocities, as well as lower amplitudes of compound motor action potentials and sensory nerve action potentials in all tested nerves (P < 0.05). Forty-eight of the 50 neuronal intranuclear inclusion disease patients (96%) had at least one abnormal electrophysiological parameter, with slowing of motor nerve conduction velocities being the most prevalent characteristic. The motor nerve conduction velocities of median, ulnar, peroneal and tibial nerves were 44.2 ± 5.5, 45.3 ± 6.1, 37.3 ± 5.3 and 35.6 ± 5.1 m/s, respectively, which were 12.4-13.6 m/s slower than those of the controls. The electrophysiological features were similar between neuronal intranuclear inclusion disease patients manifesting with CNS symptoms and those with PNS-predominant presentations. Thirteen of the 14 patients (93%) who underwent nerve conduction study within the first year of symptom onset exhibited abnormal findings, indicating that clinical or subclinical peripheral neuropathy is an early disease marker of neuronal intranuclear inclusion disease. We then assessed the feasibility of using motor nerve conduction velocity as a diagnostic tool of neuronal intranuclear inclusion disease and evaluated the diagnostic performance of various combinations of nerve conduction parameters using receiver operating characteristic curve analysis. The criterion of having at least two nerves with motor nerve conduction velocity ranging from 35 to 50 m/s in median/ulnar nerves and 30-40 m/s in tibial/peroneal nerves demonstrated high sensitivity (90%) and specificity (99%), with an area under the curve of 0.95, to distinguish neuronal intranuclear inclusion disease patients from healthy controls. The criterion's diagnostic performance was validated on an independent cohort of 56 literature reported neuronal intranuclear inclusion disease cases (area under the curve = 0.93, sensitivity = 87.5%, specificity = 99.0%), and in distinguishing neuronal intranuclear inclusion disease from genetically unresolved leukoencephalopathy cases (sensitivity = 90.0%, specificity = 80.0%). In conclusion, mildly to moderately decreased motor nerve conduction velocity in multiple nerves is a significant electrophysiological hallmark assisting the diagnosis of neuronal intranuclear inclusion disease, regardless of CNS- or PNS-predominant manifestations.

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.

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.

Rapidly progressive adult-onset neuronal intranuclear inclusion disease beginning with autonomic symptoms: a case report

Background

Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disease that can affect the nervous and other systems of the body. Its clinical manifestations are complex and easily misdiagnosed. Adult-onset NIID beginning with autonomic symptoms such as recurrent hypotension, profuse sweating, and syncope has not been reported.

Case presentation

An 81-year-old male was admitted to the hospital in June 2018 due to repeated episodes of hypotension, profuse sweating, pale complexion, and syncope for 3 years, and progressive dementia for 2 years. DWI was not possible due to the presence of metal residues in the body. Cutaneous histopathology revealed sweat gland cell nuclear inclusions and immunohistochemistry showed p62 nuclear immunoreactivity. Blood RP-PCR identified an abnormal GGC repeat expansion in the 5'UTR of the NOTCH2NLC gene. Accordingly, this case was diagnosed as adult-onset NIID in August 2018. The patient subsequently received vitamin C nutritional support, rehydration, and other vital signs maintenance treatments during hospitalization, but the above symptoms still recurred after discharge. With the development of the disease, lower extremity weakness, slow movement, dementia, repeated constipation, and vomiting appeared successively. In April 2019, he was hospitalized again for severe pneumonia, and died of multiple organ failure in June 2019.

Conclusion

The presented case exemplifies great clinical heterogeneity of NIID. Some patients may have neurological symptoms and other systemic symptoms simultaneously. This patient started with autonomic symptoms, including recurrent episodes of hypotension, profuse sweating, pallor, and syncope, which progressed rapidly. This case report provides new information for the diagnosis of NIID.

Unraveling rare form of adult-onset NIID by characteristic brain MRI features: A single-center retrospective review

Adult-onset neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disorder with high clinical heterogeneity. Previous studies indicated that the high-intensity signals in the corticomedullary junction on diffusion-weighted imaging (DWI) on brain MRI, known as the "ribbon sign," could serve as a strong diagnostic clue. Here we used the explorative approach to study the undiagnosed rate of adult-onset NIID in a single center in China via searching for the ribbon sign in picture archive and communication system (PACS) and report the clinical and radiological features of initially undiagnosed NIID patients. Consecutive brain MRI of 21,563 adult individuals (≥18 years) in the PACS database in 2019 from a tertiary hospital were reviewed. Of them, 4,130 were screened out using the keywords "leukoencephalopathy" and "white matter demyelination." Next, all 4,130 images were read by four neurologists. The images with the suspected ribbon sign were reanalyzed by two neuroradiologists. Those with the ribbon sign but without previously diagnosed NIID were invited for skin biopsy and/or genetic testing for diagnostic confirmation. The clinical features of all NIID patients were retrospectively reviewed. Five patients with high-intensity in the corticomedullary junction on DWI were enrolled. Three patients were previously diagnosed with NIID confirmed by genetic or pathological findings and presented with episodic encephalopathy or cognitive impairment. The other two patients were initially diagnosed with limb-girdle muscular dystrophy (LGMD) with rimmed vacuoles (RVs) and normal pressure hydrocephalus (NPH) in one each. Genetic analysis demonstrated GGC repeat expansion in the NOTCH2NLC gene of both, and skin biopsy of the first patient showed the presence of intranuclear hyaline inclusion bodies. Thus, five of the 21,563 adult patients (≥18 years) were diagnosed with NIID. The distinctive subcortical high-intensity signal on DWI was distributed extensively throughout the lobes, corpus callosum, basal ganglia, and brainstem. In addition, T2-weighted imaging revealed white matter hyperintensity of Fazekas grade 2 or 3, atrophy, and ventricular dilation. Distinctive DWI hyperintensity in the junction between the gray and white matter can help identify atypical NIID cases. Our findings highly suggest that neurologists and radiologists should recognize the characteristic neuroimaging pattern of NIID.

A Case of Acute Reversible Encephalopathy with Neuronal Intranuclear Inclusion Disease Diagnosed by a Brain Biopsy: Inferring the Mechanism of Encephalopathy from Radiological and Histological Findings

A 75-year-old man presented with headache and disturbance of consciousness. Magnetic resonance imaging revealed edema localized mainly in the cortex and linear contrast enhancement. A brain biopsy revealed numerous astrocytes with inclusion, and genetic testing demonstrated prolonged GGC repeats in NOTCH2NLC. The present case provided two novel insights into the mechanism underlying encephalopathy associated with neuronal intranuclear inclusion disease. First, the histological findings at a site with contrast enhancement on magnetic resonance imaging did not demonstrate any organic association, such as the presence of inflammation or ischemic changes. Second, the imaging and cerebrospinal fluid findings demonstrated increased cerebral blood flow and opening of the blood-brain barrier, indicating the cause of the cerebral swelling.

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.

Adult-onset neuronal intranuclear inclusion disease, with both stroke-like onset and encephalitic attacks: a case report

Background

Neuronal intranuclear inclusion disease (NIID) is a neurodegenerative disease, the clinical manifestations of which are complex and easily misdiagnosed. NIID clinical characteristics are varied, affecting the central and peripheral nervous systems and autonomic nerves. In this study, we present an NIID case with both stroke-like onset and encephalitic attacks, which is a rare case report.

Case presentation

A 68-year-old Chinese female presented with sudden aphasia and limb hemiplegia as the first symptoms, as well as fever, cognitive impairment and mental irritability from encephalitic attacks. During hospitalization, a brain magnetic resonance imaging (MRI) examination detected high signal intensity from diffusion-weighted imaging (DWI) of the bilateral frontal grey matter-white matter junction. Electrophysiological tests revealed the main site of injury was at the myelin sheath in the motor nerves. A skin biopsy revealed eosinophilic spherical inclusion bodies in the nuclei of small sweat gland cells, fibroblasts and fat cells, whilst immunohistochemistry revealed that p62 and ubiquitin antibodies were positive. From genetic analyses, the patient was not a carrier of the fragile X mental retardation 1 (FMR1) permutation, but repeated GGC sequences in the NOTCH2NLC gene confirmed an NIID diagnosis. Through antipsychotic and nutritional support therapy, the patient’s symptoms were completely relieved within 3 weeks.

Conclusions

This report of an NIID case with both stroke-like onset and encephalitic attacks provides new information for NIID diagnoses, and a comprehensive classification of clinical characteristics.

Neuronal intranuclear inclusion disease mimicking acute cerebellitis: A case report

BACKGROUND

Neuronal intranuclear inclusion disease (NIID) is an unusual autosomal dominant, chronic progressive neurodegenerative disease. The clinical manifestations of NIID are complex and varied, complicating its clinical diagnosis. To the best of our knowledge, this report is the first to document sporadic adult-onset NIID mimicking acute cerebellitis (AC) that was finally diagnosed by imaging studies, skin biopsy, and genetic testing.

CASE SUMMARY

A 63-year-old man presented with fever, gait unsteadiness, dysarthria, and an episode of convulsion. His serum levels of white blood cells and C-reactive protein were significantly elevated. T2-weighted brain magnetic resonance imaging and fluid attenuation inversion recovery sequences showed bilateral high-intensity signals in the medial part of the cerebellar hemisphere beside the vermis. While we initially considered a diagnosis of AC, the patient’s symptoms improved significantly without special treatment, prompting our consideration of NIID. Diffusion-weighted imaging showed hyperintensity in the corticomedullary junction. Skin biopsy revealed eosinophilic inclusions positive for anti-p62 in epithelial sweat-gland cells. GGC repeat expansions in the Notch 2 N-terminal like C gene confirmed the diagnosis of NIID.

CONCLUSION

For patients with clinical manifestations mimicking AC, the possibility of underlying NIID should be considered along with prompt rigorous examinations.

Neuronal intranuclear inclusion disease with mental abnormality: a case report

Background

Neuronal intranuclear inclusion disease (NIID) is a chronic progressive neurodegenerative disease that is characterized by the discovery of eosinophilic hyaline intranuclear inclusions in the central and peripheral nervous systems and visceral organs. In this paper, we report a case of an adult-onset neuronal intranuclear inclusion disease presenting with mental abnormality in China.

Case presentation

A 62-year-old woman presented with mental abnormality and forgetfulness for 3 months before she was admitted to our hospital. There were prodromal symptoms of fever before she had the mental disorder. Encephalitis was first suspected, and the patient underwent lumbar puncture and brain magnetic resonance imaging (MRI). A cerebrospinal fluid (CSF) examination indicated normal pressure, a normal white blood cell count, and slightly elevated protein and glucose levels. Coxsackie B virus, enterovirus, and cytomegalovirus tests showed normal results. Bacterial culture and Cryptococcus neoformans test results were negative. The contrast-enhanced MRI of the brain was normal. The brain diffusion-weighted imaging (DWI) showed a symmetrically distributed strip-shaped hyperintensity signal of the corticomedullary junction in the bilateral frontal, parietal, and temporal lobes. We considered the diagnosis of the NIID, and therefore, skin biopsy was performed. The electron microscopy revealed that intranuclear inclusions in the nucleus of fibrocytes existed and were composed of filaments.

Conclusions

NIID is a rare neurodegenerative disease with diverse clinical manifestations. In clinical work, when a patient presents with abnormal mental behavior and exhibits hyperintensity signals on DWI images of the corticomedullary junction, it is crucial to consider the diagnosis 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.

A Case Report of Sporadic Adult Neuronal Intranuclear Inclusion Disease (NIID) With Stroke-Like Onset

Background: Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disease. The clinical manifestations of NIID are complex and easily misdiagnosed. Based on the current knowledge of this disease, it is usually chronic, with almost no acute cases. Stroke-like disease is an extremely rare type of NIID.

Case Presentation: A 61-year-old woman was admitted to our hospital with sudden left limb weakness. Diffusion magnetic resonance imaging (MRI) demonstrated high signal intensity in the skin-medullary junction area. Tissue pathology showed eosinophilic inclusions in the nuclei of the sweat gland cells and fat cells of the skin. Subsequent genetic analysis of the fragile X chromosome mental retardation gene 1 (FMR1) gene showed that the CGG repeat number was in the normal range, excluding fragile X-related tremor/ataxia syndrome (FXTAS). After 3 weeks of hospitalization, the patient's condition improved, and the left limb muscle strength recovered. Her symptoms were almost completely diminished after 3 months.

Conclusion: This case demonstrates the strong clinical heterogeneity of NIID. NIID can manifest as acute hemiplegia and a stroke-like attack. This case study provides new information for the diagnosis of NIID and the classification of the clinical characteristics.

Adult-onset neuronal intranuclear inclusion disease presenting with typical MRI changes

BACKGROUND

This study aims to analyze the clinical, imaging, electrophysiological, and dermatopathological features of a patient with adult-onset neuronal intranuclear inclusion disease (NIID) and to explore the diagnostic methods of adult-onset NIID.

CASE PRESENTATION

We here report a 63-year-old male with recurrent acute encephalopathy syndrome and autonomic nervous system damage syndrome characterized by sexual dysfunction and urinary and fecal dysfunction. Cranial diffusion-weighted magnetic resonance imaging (DWI) demonstrated symmetrically distributed strip-shaped high-intensity signal in bilateral fronto-occipital-parietal cortical-medullary junction. Electrophysiological test revealed that the main site of injury was myelin sheath in both motor and sensory nerves. Skin biopsy revealed eosinophilic spherical inclusion bodies in the nucleus of sweat gland epithelial cells.

CONCLUSION

This case suggests that adult NIID is a chronic neurodegenerative disease with high clinical heterogeneity. Subcortical strip-shaped high-intensity signal on DWI has high diagnostic significance. Eosinophilic intranuclear inclusion bodies detected by skin biopsy contribute to diagnosis.