Neuronal Intranuclear Inclusion Disease: A Rare Etiology for Rapidly Progressive Dementia

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.

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.

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.

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.

Case report: Neuronal intranuclear inclusion disease presenting with acute encephalopathy

Neuronal intranuclear inclusion disease (NIID), a neurodegenerative disease previously thought to be rare, is increasingly recognized despite heterogeneous clinical presentations. NIID is pathologically characterized by ubiquitin and p-62 positive intranuclear eosinophilic inclusions that affect multiple organ systems, including the brain, skin, and other tissues. Although the diagnosis of NIID is challenging due to phenotypic heterogeneity, a greater understanding of the clinical and imaging presentations can improve accurate and early diagnosis. Here, we present three cases of pathologically proven adult-onset NIID, all presenting with episodes of acute encephalopathy with protracted workups and lengthy time between symptom onset and diagnosis. Case 1 highlights challenges in the diagnosis of NIID when MRI does not reveal classic abnormalities and provides a striking example of hyperperfusion in the setting of acute encephalopathy, as well as unique pathology with neuronal central chromatolysis, which has not been previously described. Case 2 highlights the progression of MRI findings associated with multiple NIID-related encephalopathic episodes over an extended time period, as well as the utility of skin biopsy for antemortem diagnosis.

Adult-onset neuronal nuclear inclusion disease presenting with mental and behavioral disorders: A case report and literature review

Neuronal nuclear inclusion disease (NIID) is a rare and chronic progressive neurological degenerative disease. We presented a 68-year-old man with paroxysmal orientation disorder 1 year prior, mental and behavioral disorders for 2 days, and confirmed the diagnosis of NIID with skin biopsy. We suggest that patients with atypical clinical symptoms showed characteristic high signal in the dermatomedullary junction on DWI; NIID should be considered.

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.

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.

Expanding the clinical spectrum of adult-onset neuronal intranuclear inclusion disease

Neuronal intranuclear inclusion disease (NIID) is a heterogeneous neurodegenerative disease with multiple clinical subtypes. Recent breakthroughs on neuroimaging, skin biopsy and genetic testing have facilitated the diagnosis. We aim to investigate the clinical characteristics of Chinese NIID patients to further refine the spectrum. We analyzed the clinical features of 25 NIID patients from 24 unrelated families and performed skin biopsy and/or sural nerve biopsy on 24 probands. Repeat-primed PCR and fluorescence amplicon length PCR were conducted to detect GGC repeats of NOTCH2NLC. Onset age ranged from 24 to 72 years old, and the disease duration ranged from 12 h to 25 years with the mode of onset characterized as acute, recurrent or chronic progressive type. Tremor was a common phenotype, often observed in the early stages, next to dementia and paroxysmal encephalopathy. Symptoms infrequently reported such as oromandibular dystonia, recurrent vomiting, dizziness and headache of unknown origin, as well as pure peripheral neuropathy were also suggestive of NIID. Reversible leukoencephalopathy following encephalitic episodes and the absence of apparent DWI abnormality were noticed. Two genetically confirmed NIID patients failed to be identified intranuclear inclusions, and one patient was simultaneously found significant mitochondrial swelling and fingerprint profiles depositing in lysosomes. All the patients were identified abnormal GGC repeats of NOTCH2NLC. We identify some atypical clinicopathological features and consider that pathological examinations combined with genetic testing is the gold standard for diagnosis. Whether lysosomal and mitochondrial dysfunction is involved in the pathogenesis of NIID deserves further study.

Cognitive Dysfunction in Repeat Expansion Diseases: A Review

With the development of the sequencing technique, more than 40 repeat expansion diseases (REDs) have been identified during the past two decades. Moreover, the clinical features of these diseases show some commonality, and the nervous system, especially the cognitive function was affected in part by these diseases. However, the specific cognitive domains impaired in different diseases were inconsistent. Here, we survey literature on the cognitive consequences of the following disorders presenting cognitive dysfunction and summarizing the pathogenic genes, epidemiology, and different domains affected by these diseases. We found that the cognitive domains affected in neuronal intranuclear inclusion disease (NIID) were widespread including the executive function, memory, information processing speed, attention, visuospatial function, and language. Patients with C9ORF72-frontotemporal dementia (FTD) showed impairment in executive function, memory, language, and visuospatial function. While in Huntington's disease (HD), the executive function, memory, and information processing speed were affected, in the fragile X-associated tremor/ataxia syndrome (FXTAS), executive function, memory, information processing speed, and attention were impaired. Moreover, the spinocerebellar ataxias showed broad damage in almost all the cognitive domains except for the relatively intact language ability. Some other diseases with relatively rare clinical data also indicated cognitive dysfunction, such as myotonic dystrophy type 1 (DM1), progressive myoclonus epilepsy (PME), Friedreich ataxia (FRDA), Huntington disease like-2 (HDL2), and cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS). We drew a cognitive function landscape of the related REDs that might provide an aspect for differential diagnosis through cognitive domains and effective non-specific interventions for these diseases.

Perfusion abnormality in neuronal intranuclear inclusion disease with stroke-like episode: A case report

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A patient with NIID developed stroke-like symptoms.

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The perfusion abnormality may be one of the causes of acute episodes in NIID.

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NIID should be considered as a stroke mimic.

Neuronal intranuclear inclusion disease (NIID) is a slowly progressive neurodegenerative disease. Some patients with NIID occasionally present with acute symptoms. However, its mechanism remains unclear. We report a patient with NIID who presented with a stroke-like episode. Arterial spin labeling magnetic resonance imaging revealed hypoperfusion in the focal cerebral region at the onset while no apparent arterial occlusion was observed. The abnormal perfusion area was normalized 6 days after admission. Therefore, the perfusion abnormality was likely the main cause of acute neurologic deficits in NIID. NIID should be considered in the differential diagnosis of stroke mimics.

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.

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.

Neuronal intranuclear inclusion disease presenting with dysphagia: a report of three cases

Neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disease that is pathologically characterized by the presence of eosinophilic hyaline intranuclear inclusions in neurons, astrocytes, and specific somatic cells. Previously reported cases of NIID displayed various neurological symptoms, including dementia, muscle weakness, ataxia, etc. However, dysphagia associated with NIID have rarely been reported. Here, we report on three cases of NIID with dysphagia. Bolus mastication and transport were impaired in all three cases. Delay of the initiation of pharyngeal swallowing and silent aspiration was observed in two cases. Combined with the brain magnetic resonance imaging (MRI) findings, oropharyngeal dysphagia associated with NIID was suggested to be attributed to diffuse subcortical lesions.

Identifying patients with neuronal intranuclear inclusion disease in Singapore using characteristic diffusion-weighted MR images

PURPOSE

Adult-onset neuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disorder described mainly in the Japanese population, with characteristic DWI abnormalities at the junction between gray and white matter. We identify possible cases of NIID in the picture archive and communication system (PACS) of a tertiary neurological referral hospital in Singapore and describe their radiological features.

METHODS

The neuroradiology imaging database was reviewed using keyword search of radiological reports to identify patients who had "subcortical U fibre" abnormalities on DWI. MRI were retrospectively reviewed, and those fulfilling inclusion criteria were invited for skin biopsy to detect nuclear inclusions by light and electron microscopy.

RESULTS

Twelve Chinese patients (nine female; median age 70.5 years) were enrolled. Seven patients were being assessed for dementia and five for other neurological indications. In all patients, DWI showed distinctive subcortical high signal with increased average apparent diffusion coefficient (ADC), involving frontal, parietal, and temporal more than occipital lobes; the corpus callosum and external capsule were affected in some patients. On T2-weighted images, cerebral and cerebellar atrophy and white matter hyperintensity of Fazekas grade 2 and above were seen in all patients. Three patients underwent skin biopsy; all were positive for intranuclear hyaline inclusion bodies on either p62 staining or electron microscopy, which are pathognomonic for NIID.

CONCLUSION

Previously undiagnosed patients with NIID can be identified by searching for abnormalities at the junction between gray and white matter on DWI in PACS and subsequently confirmed by skin biopsy. Radiologists should recognize the distinctive neuroimaging pattern of this dementing disease.