NOTCH2NLC Intermediate‐Length Repeat Expansions Are Associated with Parkinson Disease

NOTCH2NLC GGC repeat expansions were recently identified in neuronal intranuclear inclusion disease (NIID); however, it remains unclear whether they occur in other neurodegenerative disorders. This study aimed to investigate the role of intermediate‐length NOTCH2NLC GGC repeat expansions in Parkinson disease (PD). We screened for GGC repeat expansions in a cohort of 1,011 PD patients and identified 11 patients with intermediate‐length repeat expansions ranging from 41 to 52 repeats, with no repeat expansions in 1,134 controls. Skin biopsy revealed phospho‐alpha‐synuclein deposition, confirming the PD diagnosis in 2 patients harboring intermediate‐length repeat expansions instead of NIID or essential tremor. Fibroblasts from PD patients harboring intermediate‐length repeat expansions revealed NOTCH2NLC upregulation and autophagic dysfunction. Our results suggest that intermediate‐length repeat expansions in NOTCH2NLC are potentially associated with PD. ANN NEUROL 2021;89:182–187     

NOTCH2NLC GGC Repeat Expansions Are Associated with Sporadic Essential Tremor: Variable Disease Expressivity on Long-Term Follow-up

We screened 662 subjects comprising 462 essential tremor (ET) subjects (285 sporadic, 125 with family history, and 52 probands from well-characterized ET pedigrees) and 200 controls and identified pathogenic NOTCH2NLC GGC repeat expansions in 4 sporadic ET patients. Two patients were followed up for >1 decade; one with 90 repeats remained an ET phenotype that did not evolve after 40 years, whereas another patient with 107 repeats developed motor symptoms and cognitive impairment after 8 to 10 years. Neuroimaging in this patient revealed severe leukoencephalopathy; diffusion-weighted imaging hyperintensity in the corticomedullary junction and skin biopsy revealed intranuclear inclusions suggestive of intranuclear inclusion body disease (NIID). No GGC repeats of >60 units were detected in familial ET cases and controls, although 4 ET patients carried 47 to 53 “intermediate” repeats. NOTCH2NLC GGC repeat expansions can be associated with sporadic ET. Carriers presenting with a pure ET phenotype may or may not convert to NIID up to 4 decades after initial tremor onset. ANN NEUROL 2020;88:614–618     

First detailed case report of a pediatric patient with neuronal intranuclear inclusion disease diagnosed by NOTCH2NLC genetic testing

IntroductionNeuronal intranuclear inclusion disease (NIID) is a rare neurodegenerative disease characterized clinically by eosinophilic hyaline intranuclear inclusions in neuronal and other somatic cells. Skin biopsies are reportedly useful in diagnosing NIID, and the genetic cause of NIID was identified as a GGC repeat expansion in NOTCH2NLC in recent years. The number of adult patients diagnosed via genetic testing has increased; however, there have been no detailed reports of pediatric NIID cases with GGC expansions in NOTCH2NLC. This is the first detailed report of a pediatric patient showing various neurological symptoms from the age of 10 and was ultimately diagnosed with NIID via skin biopsy and triplet repeat primed polymerase chain reaction analyses.Case reportThis was an 18-year-old female who developed cyclic vomiting, distal dominant muscle weakness, and sustained miosis at 10 years. Nerve conduction studies revealed axonal degeneration, and her neuropathy had slowly progressed despite several rounds of high-dose methylprednisolone and intravenous immunoglobulin therapy. At 13 years, she had an acute encephalopathy-like episode. At 15 years, brain MRI revealed slightly high-intensity lesions on diffusion-weighted and T2-weighted imaging in the subcortical white matter of her frontal lobes that expanded over time. At 16 years, esophagography, upper gastrointestinal endoscopy, and esophageal manometry revealed esophageal achalasia, and per-oral endoscopic myotomy was performed. At 18 years, we diagnosed her with NIID based on the findings of skin specimen analyses and a GGC repeat expansion in NOTCH2NLC.ConclusionNIID should be considered as a differential diagnosis in pediatric patients with various neurological symptoms.     

Novel heterozygous NOTCH3 pathogenic variant found in two Chinese patients with CADASIL

NOTCH3 mutations have been described to cause cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Here, we report 2 CADASIL patients from a Chinese family. Whole genome sequencing was performed on the two CADASIL patients. The novel variant c.128G>C in exon 2 of NOTCH3 was identified and confirmed through PCR-Sanger sequencing (Human Genome Variation Society nomenclature: HGVS: NOTCH3 c.128G>C; p.Cys43Ser). The heterozygous NOTCH3 variant cause a cysteine to serine substitution at codon 43. According to the variant interpretation guideline of American College of Medical Genetics and Genomics (ACMG), this variant was classified as “pathogenic”. Other variants in HTRA1, COL4A1 and COL4A2 were also found, they were classified as “benign”.     

Population-specific spectrum of <Emphasis Type="Italic">NOTCH3</Emphasis> mutations,MRI features and founder effect of CADASIL in Chinese

Background and purpose   Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary disorder caused by NOTCH3 mutations and characterized by recurrent subcortical infarctions, dementia and leukoencephalopathy. So far, most clinical, molecular and neuroimaging information has come from Caucasians. Therefore, we investigated the spectrum of NOTCH3 mutations and MRI features in CADASIL patients of Chinese origin on Taiwan. Methods   Mutational analysis of NOTCH3 exons 2 to 23 by direct nucleotide sequencing was performed in patients with clinically suspected CADASIL. MRI findings were retrospectively evaluated and scored using a modified Schelten’s scale. Results   Nine different point mutations of NOTCH3 were identified in 21 unrelated patients. Intriguingly, 47.6 % were in exon 11, and 19 % in each of exon 4 and 18. R544C was very common and present in all patients with a mutation in exon 11. Many patients with NOTCH3 R544C share the same haplotype linked to the mutation using markers D19S929 and D19S411, which flank the NOTCH3. The sensitivity of T2-weighted MRI detecting anterior temporal abnormality was only 42.9 %. Furthermore, the neuroimaging evidence of intracerebral hemorrhage (ICH) was present in 23.8 % of the 21 patients. Conclusions   A population-specific mutational spectrum of CADASIL was found in the Chinese patients on Taiwan. The Chinese patients carrying NOTCH3 R544C may descend from a common ancestor. Anterior temporal hyperintensity on T2-weighted MRI may not be a sensitive marker for CADASIL. ICH is a relatively common manifestation of CADASIL in East Asians, especially in the presence of hypertension.     

Mitochondrial DNA sequence variation and mutation rate in patients with CADASIL

Mutations in the NOTCH3 gene cause cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), which is clinically characterised by recurrent ischemic strokes, migraine with aura, psychiatric symptoms, cognitive decline and dementia. We have previously described a patient with CADASIL caused by a R133C mutation in the NOTCH3 gene and with a concomitant myopathy caused by a 5650G>A mutation in the MTTA gene in mitochondrial DNA (mtDNA). We assume that the co-occurrence of the two mutations is not coincidental and that mutations in the NOTCH3 gene may predispose the mtDNA to mutations. We therefore examined the nucleotide variation in the mtDNA coding region sequences in 20 CADASIL pedigrees with 77 affected patients by conformation-sensitive gel electrophoresis and sequencing. The sequence variation in mtDNA was then compared with that among 192 healthy Finns. A total of 180 mtDNA coding region sequence differences were found relative to the revised Cambridge reference sequence, including five novel synonymous substitutions, two novel nonsynonymous substitutions and one novel tRNA substitution. We found that maternal relatives in two pedigrees differed from each other in their mtDNA. Furthermore, the average number of pairwise differences in sequences from the 41 unrelated maternal lineages with CADASIL was higher than that expected among haplogroup-matched controls. The numbers of polymorphic sites and polymorphisms that were present in only one sequence were also higher among the CADASIL sequences than among the control sequences. Our results show that mtDNA sequence variation is increased within CADASIL pedigrees. These findings suggest a relationship between NOTCH3 and mtDNA.An erratum to this article can be found at     

Diagnostic criteria for adult‐onset leukoencephalopathy with axonal spheroids and pigmented glia due to CSF1R mutation

Background and purpose

To establish and validate diagnostic criteria for adult‐onset leukoencephalopathy with axonal spheroids and pigmented glia (ALSP) due to colony‐stimulating factor 1 receptor (CSF1R) mutation.

Methods

We developed diagnostic criteria for ALSP based on a recent analysis of the clinical characteristics of ALSP. These criteria provide ‘probable’ and ‘possible’ designations for patients who do not have a genetic diagnosis. To verify its sensitivity and specificity, we retrospectively applied our criteria to 83 ALSP cases who had CSF1R mutations (24 of these were analyzed at our institutions and the others were identified from the literature), 53 cases who had CSF1R mutation‐negative leukoencephalopathies and 32 cases who had cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) with NOTCH3 mutations.

Results

Among the CSF1R mutation‐positive cases, 50 cases (60%) were diagnosed as ‘probable’ and 32 (39%) were diagnosed as ‘possible,’ leading to a sensitivity of 99% if calculated as a ratio of the combined number of cases who fulfilled ‘probable’ or ‘possible’ to the total number of cases. With regard to specificity, 22 cases (42%) with mutation‐negative leukoencephalopathies and 28 (88%) with CADASIL were correctly excluded using these criteria.

Conclusions

These diagnostic criteria are very sensitive for diagnosing ALSP with sufficient specificity for differentiation from CADASIL and moderate specificity for other leukoencephalopathies. Our results suggest that these criteria are useful for the clinical diagnosis of ALSP.     

Genotypic and phenotypic spectrum of CADASIL in Japan: the experience at a referral center in Kumamoto University from 1997 to 2014

This study elucidates the genotypic and phenotypic spectrum and histopathological findings related to cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) in Japan. For this single-center retrospective observational study, we enrolled 215 patients who were clinically suspected of having CADASIL and were examined at Kumamoto University from 1997 to 2014, and we diagnosed CADASIL in 70 patients. We found 19 different NOTCH3 mutations in the patients, with the NOTCH3 Arg133Cys mutation being found most frequently. We also found the Arg75Pro mutation, a cysteine-sparing NOTCH3 mutation. CADASIL patients with this Arg75Pro mutation were frequently found throughout Japan, and fewer patients with the Arg75Pro mutation showed MRI hyperintensity in the anterior temporal pole compared with patients with other NOTCH3 mutations. Significantly more CADASIL patients with the NOTCH3 Arg133Cys mutation had hyperintensity in the external capsule compared with CADASIL patients with the other mutations not including the NOTCH3 Arg75Pro mutation. We also showed postmortem pathological findings of the first Japanese CADASIL case with the NOTCH3 Arg133Cys mutation, and histopathological findings of fresh frozen skin biopsy specimens of CADASIL patients. In conclusions, the spectrum of NOTCH3 mutations in Japanese CADASIL patients may be partially explained by founder effects. Genotype–phenotype correlations may exist in CADASIL, which should be considered so as to make an accurate diagnosis of CADASIL in each population. Fresh frozen skin biopsy specimens may aid detection of Notch3 deposits on vascular walls for an improved diagnosis of CADASIL.     

NOTCH2NLC-related repeat expansion disorders: an expanding group of neurodegenerative disorders

Neurological Sciences - The NOTCH2NLC gene 5′ untranslated region (UTR) GGC repeat expansion mutations were identified as a genetic contributor of neuronal intranuclear inclusion disease...     

CADASIL: Extended polymorphisms and mutational analysis of the NOTCH3 gene

CADASIL is a cerebrovascular disease caused by mutations in the NOTCH3 gene. Most mutations result in a gain or loss of cysteine residue in one of the 34 epidermal growth factor‐like repeats in the extracellular domain of the Notch3 protein, thus sparing the number of cysteine residues. To date, more than 130 different mutations in the NOTCH3 gene have been reported in CADASIL patients, of which 95% are missense point mutations. Many polymorphisms have also been identified in the NOTCH3 coding sequence, some of them leading to amino acid substitutions. The aim of the present study was to analyze the NOTCH3 gene in a large group of patients affected by leukoencephalopathy and to investigate the presence of genetic variants. The molecular analysis revealed several nucleotide alterations. In particular, we identified 20 different mutations, 22 polymorphisms, and 8 genetic variants of unknown pathological significance never reported previously. We hope that this NOTCH3 gene mutational analysis, performed in such a significant number of unrelated and related patients affected by leukoencephalopathy, will help in molecular screening for the NOTCH3 gene, thus contributing to enlargement of the NOTCH3 gene variation database. © 2008 Wiley‐Liss, Inc.     

Characteristics of ocular findings of patients with neuronal intranuclear inclusion disease

Neurological Sciences - This study aimed to explore the ocular characteristics of neuronal intranuclear inclusion disease (NIID), caused by GGC repeat expansion in the NOTCH2NLC gene, combined with...     

First report of a pathogenic mutation on exon 24 of the <Emphasis Type="Italic">NOTCH3</Emphasis> gene in a CADASIL family

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a genetically transmitted small vessel disease clinically characterized by migraine, recurrent subcortical strokes, and cognitive and mood disorders. Pathogenic mutations are located on any of the exons of the NOTCH3 gene coding for epidermal-growth factor (EGF)-like repeats of the extracellular domain of the NOTCH3 receptor. Because the gene is large and the mutations cluster on some exons, many laboratories restrict the analysis to these exons. We report the first missense mutation involving exon 24 and causing CADASIL in a 64-year-old man. The patient was admitted to the hospital for a loss of consciousness accompanied by profuse sweating. On examination, some parkinsonian features were present. Over the last 4 years, he had developed postural instability and gait disturbances with repeated falls, behavioral disorders, and cognitive impairment. A diagnostic hypothesis of atypical parkinsonism had been advanced. The presence of multiple subcortical lacunar infarcts and leukoencephalopathy extended to the external capsule on cerebral MRI suggested the presence of CADASIL. The diagnosis was confirmed by finding a heterozygous mutation leading to a cysteine substitution on exon 24 of the NOTCH3 gene. One proband’s brother, who had progressive gait disturbances, unilateral action tremor and bradykinesia, and an asymptomatic niece also resulted affected. This report underlines that when CADASIL is suspected the genetic analysis should be performed on all the NOTCH3 exons coding for EGF-like repeats including exon 24 and confirms that CADASIL may have heterogeneous phenotypes.     

Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts and Leukoencephalopathy Associated With a Novel In-Frame Mutation in the NOTCH3 Gene in a Japanese Patient

Here, we report a case involving a 67-year-old Japanese woman with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) associated with a novel in-frame complex rearrangement in the NOTCH3 gene. The patient had gradually developed cognitive impairment since the occurrence of an ischemic stroke at the age of 53 years. Her mother had a history of stroke and dementia. Fluid-attenuated inversion recovery magnetic resonance imaging of the brain showed hyperintense lesions in the bilateral temporal poles, external capsules, and periventricular white matter accompanied by multiple cerebral microbleeds on T2*-weighted gradient-echo imaging. A novel in-frame mutation (c.598_610delinsAGAACCC) resulting in the loss of Cys201 in the fifth epidermal growth factor-like repeat of NOTCH3 was identified; this led to a diagnosis of CADASIL. In summary, we report a novel pathogenic mutation (NOTCH3 c.598_610delinsAGAACCC; p.Pro200_Ser204delinsArgThrPro) associated with CADASIL. Further investigations should elucidate the genotype-phenotype correlations in patients with this in-frame complex rearrangement.     

Is the SHRPS strain a suitable model of spontaneous CADASIL?

A number of features of the pathology occurring in spontaneously hypertensive stroke prone rats (SHRSPs), such as MRI brain signal abnormalities, the presence of high protein content in cerebrospinal fluid and vessel wall thickening, seem to indicate that this strain is a suitable model for cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). To explore this hypothesis, we sought the human diagnostic hallmarks of the disease [the accumulation of granular osmiophilic material (GOM) deposits in vessel walls and NOTCH3 gene mutations] in SHRSPs. Male SHRSPs fed a permissive diet were sacrificed 3 days after the first MRI visualisation of brain abnormalities. Whole blood and kidney samples were respectively collected for molecular and electron microscopy evaluations. Automated sequence analysis of exons and intron–exon boundaries did not reveal any genetic variation in the NOTCH3 gene, and electron microscopy excluded the presence of GOM. The findings of this study exclude SHRSPs as a possible model for CADASIL.     

Status epilepticus no convulsivo como manifestación inicial en una familia con arteriopatía autosómica dominante cerebral con infartos subcorticales y leucoencefalopatía (CADASIL)

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an autosomal dominant small-vessel disease caused by mutations of the NOTCH3 gene. It typically presents with migraine, recurrent brain ischaemia, and cognitive disorders. Seizures rarely present as the initial manifestation, with non-convulsive status epilepticus being even less frequent. We present a series of 3 related patients with this arteriopathy, 2 of whom presented status epilepticus as a manifestation of the disease.     

Pericytes as a new target for pathological processes in CADASIL

CADASIL is a generalized angiopathy caused by mutations in NOTCH 3 gene leading to degeneration and loss of vascular smooth muscle cells (VSMC) in small arteries and arterioles. Since the receptor protein encoded by NOTCH 3 gene is expressed not only on VSMC but also on pericytes, pericytes and capillary vessels can be damaged by CADASIL. To check this hypothesis we examined microvessels in autopsy brains and skin‐muscle biopsies of CADASIL patients. We found degeneration and loss of pericytes in capillary vessels. Pericytes were shrunken and their cytoplasm contained numerous vacuoles, big vesicular structures and complexes of enlarged pathological mitochondria. Degenerative changes were also observed within endothelial‐pericytic connections, especially within peg‐and‐socket junctions. Nearby pericyte cell membranes or inside infoldings, deposits of granular osmiophilic material (GOM) were usually seen. In the affected capillaries endothelial cells revealed features of degeneration, selective death or swelling, leading to narrowing or occlusion of the capillary lumen. Our findings indicate that in CADASIL not only VSMC but also pericytes are severely damaged. Pericyte involvement in CADASIL can result in increased permeability of capillary vessels and disturbances in cerebral microcirculation, leading to white matter injury. Since in capillaries pericytes regulate vessel contractility, their degeneration can also cause defective vasomotor reactivity, the phenomenon observed very early in CADASIL, before development of histopathological changes in vessel walls.     

The CADASIL Scale-J,A Modified Scale to Prioritize Access to Genetic Testing for Japanese CADASIL-Suspected Patients

Background: Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is definitely diagnosed by genetic testing. Such testing involves the analysis of exons 2-24 of NOTCH3, which encode the epidermal growth factor-like repeat domain, where CADASIL mutations are localized. We previously reported clinical diagnostic criteria for screening CADASIL-suspected Japanese patients prior to genetic testing. Because of its high sensitivity but low specificity, most patients need to undergo genetic testing. In this study, we aimed to develop the CADASIL scale-J, a modified scale to prioritize access to genetic testing for CADASIL-suspected Japanese patients. Methods: We modified the CADASIL scale reported by Pescini et al based on clinical features of 126 CADASIL patients and 53 NOTCH3-negative CADASIL-like patients diagnosed up until March 2016 (Phase 1). For validation, we recruited 69 consecutive patients for genetic testing of NOTCH3 from April 2016 to March 2017 (Phase 2). Results: We developed the CADASIL scale-J with a score ranging from 0 to 25 and the cut-off value of 16, using 8 items: hypertension, diabetes, young onset (≤50 years old), pseudobulbar palsy, stroke/TIA, family history, subcortical infarction, and temporal pole lesion. The sensitivity and specificity of the CADASIL scale-J were 78.9% and 85.7%, respectively. In Phase 2, we obtained a positive predictive value of 70.0% and a negative predictive value of 89.2%. In this study, we identified 54 mutations, 7 of which were novel. Conclusions: The CADASIL scale-J is helpful to prioritize access to genetic testing for CADASIL-suspected Japanese patients.     

Parkinsonism in a pair of monozygotic CADASIL twins sharing the R1006C mutation: a transcranial sonography study

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), the most common hereditary cerebral small vessel disease, is caused by mutations in the NOTCH3 gene on chromosome 19. Clinical manifestations of CADASIL include recurrent transient ischemic attacks, strokes, cognitive defects, epilepsy, migraine and psychiatric symptoms. Parkinsonian features have variably been reported in CADASIL patients, but only a few patients showed a clear parkinsonian syndrome. We studied two patients, a pair of monozygotic twins, carrying the R1006C mutation of the NOTCH3 gene and affected by a parkinsonian syndrome. For the first time in CADASIL patients, we used transcranial sonography (TCS) to assess basal ganglia abnormalities. TCS showed a bilateral hyperechogenic pattern of substantia nigra in one twin, and a right hyperechogenic pattern in the other. In both patients, lenticular nuclei showed a bilateral hyperechogenic pattern, and the width of the third ventricle was slightly increased. The TCS pattern found in our CADASIL patients is characteristic neither for Parkinson’s disease, nor for vascular parkinsonism and seems to be specific and related to the disease-specific pathological features.     

COL4A2 mutation causing adult onset recurrent intracerebral hemorrhage and leukoencephalopathy

Type IV collagen α1 and α2 chains form heterotrimers that constitute an essential component of basement membranes. Mutations in COL4A1, encoding the α1 chain, cause a multisystem disease with prominent cerebrovascular manifestations, including porencephaly, bleeding-prone cerebral small vessel disease, and intracranial aneurysms. Mutations in COL4A2 have only been reported in a few porencephaly families so far. Herein, we report on a young adult patient with recurrent intracerebral hemorrhage, leukoencephalopathy, intracranial aneurysms, nephropathy, and myopathy associated with a novel COL4A2 mutation. We extensively investigated a 29-year-old male patient with recurrent deep intracerebral hemorrhages causing mild motor and sensory hemisyndromes. Brain MRI showed deep intracerebral hemorrhages of different age, diffuse leukoencephalopathy, multiple cerebral microbleeds and small aneurysms of the carotid siphon bilaterally. Laboratory work-up revealed significant microscopic hematuria and elevation of creatine-kinase. Genetic testing found a de novo glycine mutation within the COL4A2 triple helical domain. The presented case completes the spectrum of cerebral and systemic manifestations of COL4A2 mutations that appears to be very similar to that in COL4A1 mutations. Therefore, we emphasize the importance of screening both COL4A1 and COL4A2 in patients showing recurrent intracerebral hemorrhage of unknown etiology, particularly if associated with leukoencephalopathy.     

A new Spanish family with CADASIL associated with 346C>T mutation of NOTCH3 gene

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an adult-onset inherited condition characterized by migraine, recurrent strokes, and subcortical dementia. Other manifestations as psychiatric disturbances, seizures, hypoacusia or learning disorders have been reported. CADASIL may be suspected based on clinical syndrome, a positive family history, and a typical cranial magnetic resonance image with T2/FLAIR hyperintense signals in the temporopolar white matter or the external capsule. Bilateral white matter abnormalities are invariably seen and often small subcortical infarcts are also present. Accumulation of the granular osmiophilic material on skin biopsy may help in diagnosis. Mutations in the NOTCH3 gene localized in chromosome 19 are involved in its pathogenesis. Only 11 families from Spain have been reported. Here we describe two members of a family with clinical symptoms and neuroimaging of CADASIL. The skin biopsy was negative. In both patients 346C>T mutation in exon 3 of NOTCH3 gene was found. There is the first Spanish family reported with CADASIL, caused by the 346C > T mutation in NOTCH3 gene which was frequently described in the European series.