Nerve conduction studies in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy

Small Fiber Pathology in CADASIL: Clinical Correlation With Cognitive Impairment

BACKGROUND AND OBJECTIVES

This study investigated the cutaneous small fiber pathology of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) and its clinical significance, that is, the NOTCH3 deposition in cutaneous vasculatures and CNS neurodegeneration focusing on cognitive impairment.

METHODS

Thirty-seven patients with CADASIL and 59 age-matched healthy controls were enrolled to evaluate cutaneous small fiber pathology by quantitative measures of intraepidermal nerve fiber density (IENFD), sweat gland innervation, and vascular innervation. Cognitive performance of patients with CADASIL was evaluated by a comprehensive neuropsychological assessment, and its association with small fiber pathology was tested using multivariable linear regression analysis adjusted for age and diabetes mellitus. We further assessed the relationships of IENFD with cutaneous vascular NOTCH3 ectodomain (NOTCH3ECD) deposition and biomarkers of neurodegeneration including structural brain MRI measures, serum neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), tau, and ubiquitin carboxy-terminal hydrolase L1.

RESULTS

Patients with CADASIL showed reduced IENFD (5.22 ± 2.42 vs 7.88 ± 2.89 fibers/mm, p = 0.0001) and reduced sweat gland (p < 0.0001) and vascular (p < 0.0001) innervations compared with age-matched controls. Reduced IENFD was associated with impaired global cognition measured by Mini-Mental State Examination (B = 1.062, 95% CI = 0.370-1.753, p = 0.004), and this association remained after adjustment for age and diabetes mellitus (p = 0.043). In addition, IENFD in patients with CADASIL was associated with mean cortical thickness (Pearson r = 0.565, p = 0.0023) but not white matter hyperintensity volume, total lacune count, or total microbleed count. Reduced IENFD was associated with cutaneous vascular NOTCH3ECD deposition amount among patients harboring pathogenic variants in exon 11 (mainly p.R544C) (B = -0.092, 95% CI = -0.175 to -0.009, p = 0.031). Compared with those with normal cognition, patients with CADASIL with cognitive impairment had an elevated plasma NfL level regardless of concurrent small fiber denervation, whereas only patients with both cognitive impairment and small fiber denervation showed an elevated plasma GFAP level.

DISCUSSION

Cutaneous small fiber pathology correlates with cognitive impairment and CNS neurodegeneration in patients with CADASIL, indicating a peripheral neurodegenerative process related to NOTCH3ECD aggregation.

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) as a model of small vessel disease: update on clinical, diagnostic, and management aspects

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is the most common and best known monogenic small vessel disease. Here, we review the clinical, neuroimaging, neuropathological, genetic, and therapeutic aspects based on the most relevant articles published between 1994 and 2016 and on the personal experience of the authors, all directly involved in CADASIL research and care. We conclude with some suggestions that may help in the clinical practice and management of these patients.

Clinical and radiological features in CADASIL and NOTCH3-negative patients: a multicenter study from Turkey

BACKGROUND

The diversity of clinical presentation and neuroimaging findings of CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) from different regions of the world has not yet been studied in depth. Here we investigated the variability of clinical, radiological and genetic data of 48 patients analyzed for NOTCH3 mutation in Turkey.

METHODS

Clinical evaluation was made according to a preformed questionnaire. Cranial neuroimaging findings were determined on the basis of T1, T2, FLAIR and proton-density magnetic resonance scans. For genetic analysis, polymerase chain reaction was performed with primers flanking exons 2-6 and 11 of NOTCH3 gene.

RESULTS

Twenty-five patients (52.1%) were diagnosed as CADASIL with NOTCH3 mutation, while 23 patients (47.9%) had no mutation (NOTCH3-negative patients). The mean age and age at stroke onset were lower in male CADASIL patients (p < 0.03). A family history of migraine (p = 0.012), stroke (p < 0.001), recurrent strokes (p = 0.020) and dementia (p = 0.012) was more common in CADASIL patients. Temporal pole involvement was more common in CADASIL patients (p = 0.004).

CONCLUSION

It is of clinical importance to identify the heterogeneity of CADASIL from different countries due to a low correlation of clinical and radiological data with respect to NOTCH3 mutation.

Diversity of stroke presentation in CADASIL: study from patients harboring the predominant NOTCH3 mutation R544C

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a single-gene disorder of the cerebral small blood vessels caused by mutations in the NOTCH3 gene. Several characteristic population-specific clinical phenotypes and neuroimaging features have been reported in CADASIL. This study investigated the clinical stroke presentation and cranial magnetic resonance imaging (MRI) findings in a group of patients with CADASIL. We reviewed the clinical stroke presentation and brain MRI findings in 73 consecutive Korean patients aged >18 years diagnosed with CADASIL between May 2004 and April 2009. Brain MRI images were also scored for lacunar infarction and cerebral microbleeds. Intracranial atherosclerosis (ICAS) was assessed by magnetic resonance angiography. Disability was measured with the modified Rankin scale (mRS) and classified as good (mRS score 0-2) or poor (mRS score 3-5). In this study, 65 of the 73 patients (90.3%) had the same R544C genotype. A total of 40 episodes of cerebral infarction were confirmed in 31 patients, with a mean age at onset of 58.8 ± 11.4 years (range, 38-76 years). Twelve patients (16.9%) had ICAS, and 5 of these patients had symptomatic stenoses. Intracerebral hemorrhage occurred in 9 patients (12.3%). Both intracerebral hemorrhage and ICAS were associated with poor clinical outcome. Our data demonstrate the diversity of clinical stroke presentation according to ethnicity and vascular risk factors.

Skin and sural nerve biopsies: ultrastructural findings in the first genetically confirmed cases of CADASIL in Serbia

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited vascular disorder caused by Notch3 gene mutations. The main histopathological hallmark is granular osmiophilic material (GOM) deposited in the close vicinity of vascular smooth muscle cells (VSMCs). The authors report the first 7 ultrastructurally and genetically confirmed cases of CADASIL in Serbia. Samples of skin and sural nerve were investigated by transmission electron microscopy. GOM deposits were observed around degenerated VSMCs in all the skin biopsies examined. Sural nerve biopsies revealed severe alterations of nerve fibers, endoneurial blood vessels with GOM deposits, endoneurial fibroblasts, and perineurial myofibroblasts. Total genomic DNA was extracted from peripheral blood leukocytes, and exons 2-6 of the Notch3 gene were amplified by PCR and subsequently sequenced. Four different mutations in exons 2 (Cys65Tyr), 3 (Gly89Cys and Arg90Cys), and 6 (Ala319Cys), which determine the CADASIL disease, were detected among all described patients. A novel missense mutation Gly89Cys involving exon 3 was detected. Due to the difficulties in the determination of the Notch3 mutations, these data suggest that electron microscopic analysis for GOMs in dermal vessel wall provides a rapid and reliable screening method for this disease.

Neurological features of Fabry disease: clinical, pathophysiological aspects and therapy

Fabry disease is a multisystem, X-linked, lysosomal storage disorder caused by a mutation in the GLA gene on chromosome Xq22 resulting in alpha-galactosidase A enzyme (α-Gal A) deficiency. Neurological manifestations other than cerebrovascular accidents include small fibre neuropathy and dysautonomic disorders, which may be the presenting clinical features in a proportion of patients. An atypical disease onset may be misdiagnosed until the emergence of a more typical clinical picture, characterized by chronic renal and cardiac failure. Thus, neurologists should consider Fabry disease in differential diagnosis and provide an appropriate diagnostic work up. This review focuses on central and peripheral nervous system involving available diagnostic tools and diagnostic work up in Fabry disease. It also covers the most recent evidence regarding enzyme replacement therapy.

Effects of lacunar infarctions on cognitive impairment in patients with cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy

Background and Purpose

Cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited microangiopathy caused by mutations in the Notch3 gene. Although previous studies have shown an association between lacunar infarction and cognitive impairment, the relationship between MRI parameters and cognition remains unclear. In this study we investigated the influence of MRI parameters on cognitive impairment in CADASIL.

Methods

We applied a prospective protocol to 40 patients. MRI analysis included the normalized volume of white-matter hyperintensities (nWMHs), number of lacunes, and number of cerebral microbleeds. Cognition was assessed with the aid of psychometric tests [Mini-Mental State Examination (MMSE), Alzheimer's Disease Assessment Scale-cognition (ADAS-cog), Trail-Making Test, and Stroop interference (Stroop IF)].

Results

A multivariate regression analysis revealed that the total number of lacunes influenced the performance in the MMSE, ADAS-cog, and Stroop IF, while nWMHs had a strong univariate association with ADAS-cog and Stroop IF scores. However, this association disappeared in the multivariate analysis.

Conclusions

These findings demonstrate that the number of lacunes is the main predictive factor of cognitive impairment in CADASIL.

Screening for NOTCH3 gene mutations among 151 consecutive Korean patients with acute ischemic stroke

BACKGROUND

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a single-gene disorder of cerebral small blood vessels caused by mutations in the NOTCH3 gene. The initial detection of CADASIL may be more difficult among Asian populations because common clinical phenotypes and neuroimaging findings are not frequently found in these populations. The purpose of this study was to screen the NOTCH3 gene for mutations among consecutive patients with acute ischemic stroke from our region in Korea.

METHODS

Between April 2008 and March 2009, 151 consecutive patients with acute ischemic stroke were screened for NOTCH3 mutations. All patients underwent a detailed clinical examination and structured interview for clinical symptoms and family history. We reviewed brain magnetic resonance imaging data from stroke patients to assess the severity of white-matter hyperintensity lesions, the number of cerebral microbleeds, and the number of lacunar infarctions. Polymerase chain reaction was used to screen exons 3, 4, 6, 11, and 18 of the NOTCH3 gene.

RESULTS

Among 151 consecutive patients with acute ischemic stroke, 6 patients (4.0%; 95% confidence interval [CI] 0.9-7.1) possessed a NOTCH3 gene mutation. All patients exhibited the same R544C mutation in exon 11. Four of these 6 patients presented with large artery atherosclerosis. The prevalence of CADASIL in patients with neuroimaging features consistent with advanced small-vessel disease was 36.0% (95% CI 8.0-64.8).

CONCLUSIONS

In this region, NOTCH3 gene mutations are frequently found in acute stroke patients who present with neuroimaging features consistent with advanced small-vessel disease.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy: a genetic cause of cerebral small vessel disease

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a single-gene disorder of the cerebral small blood vessels caused by mutations in the Notch3 gene. The exact prevalence of this disorder was unknown currently, and the number of reported CADASIL families is steadily increasing as the clinical picture and diagnostic examinations are becoming more widely known. The main clinical manifestations are recurrent stroke, migraine, psychiatric symptoms, and progressive cognitive impairment. The clinical course of CADASIL is highly variable, even within families. The involvement of the anterior temporal lobe and the external capsule on brain magnetic resonance imaging was found to have high sensitivity and specificity in differentiating CADASIL from the much more common sporadic cerebral small-vessel disease (SVD). The pathologic hallmark of the disease is the presence of granular osmiophilic material in the walls of affected vessels. CADASIL is a prototype single-gene disorder that has evolved as a unique model for studying the mechanisms underlying cerebral SVD. At present, the incidence and prevalence of CADASIL seem to be underestimated due to limitations in clinical, neuroradiological, and genetic diagnoses of this disorder.