Cerebral Autosomal Dominant Arteriopathy With Subcortical Infarcts And Leucoencephalopathy Patients Research Articles

The First Report of CADASIL in Peru: Olfactory Dysfunction on Initial Presentation.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is a rare, heritable, small vessel vascular disease caused by mutations in the Notch3 gene that is characterized by migraines, subcortical vascular events, cognitive decline, and mood disturbances. However, many CADASIL cases present with unusual symptoms such as status epilepticus, a movement disorder, or sensory dysfunction. This study describes the clinical, genetic, and radiologic characteristics of a Peruvian family with CADASIL in which multiple family members presented with severe olfactory deficits. Seven members of the family have symptoms suggestive of CADASIL, with genetic testing revealing R133C mutations in the two patients who underwent genetic testing. Cognitive testing and olfactory identification testing (Smell Identification Test) were performed in three CADASIL patients revealing total anosmia in two tested patients and severe hyposmia in the other. Olfactory dysfunction has been associated with various neurologic and psychiatric conditions, though few studies have linked it with neurovascular disorders such as CADASIL. This first reported case of CADASIL in Peru emphasizes that symptomatic olfactory dysfunction may be an unusual presentation of CADASIL and that olfactory dysfunction is important to evaluate in CADASIL patients.

Longitudinal changes of cortical morphology in CADASIL

In CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leucoencephalopathy), a genetic model of subcortical ischemic vascular dementia (SIVD), clinical status was previously found related to cortex morphology. In the present report, alterations of cortex morphology and their links to clinical worsening were investigated in 190 CADASIL patients followed during 24.4 months. Linear models were used to test relationships between: (1) clinical worsening and changes of depth of cortical sulci and of cortical thickness; (2) alterations of cortical morphology and changes of volume of white matter hyperintensities (WMHv) and of lacunar lesions (LLv). Reduction of sulcal depth was independently associated with increased time to complete trail making test A and B (p < 0.0001 and p = 0.004) and that of cortical thickness to increased disability (modified Rankin's scale, p = 0.008), while brain atrophy was only related to global cognitive worsening (Mattis dementia rating scale, p = 0.002). The impact of volume of lacunar lesions on cortical alterations was larger than that of volume of white matter hyperintensities. Cortical alterations, mainly related to lacunar lesions, evolve parallel to clinical worsening. These results further support the eventual role of cortical alterations in subcortical ischemic vascular dementia.

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leucoencephalopathy and Right-to-Left Shunt: Lack of Evidence for an Association in a Prevalence Study

Background /Aims: Up to more than 50% of cryptogenetic stroke patients and patients with migraine with aura (MA) are found to have a right-to-left shunt (RLS), which is usually due to a patent foramen ovale. Moreover, both MA and stroke are cardinal features of cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL). Notch3 mutations have been suggested to induce an abnormally high incidence of atrial septal defects in a family harbouring an Arg141Cys pathogenetic mutation. We sought to determine the prevalence of RLS in CADASIL patients with different Notch3 mutations, both with and without migraine as a clinical feature. Methods: Subjects with a molecular diagnosis of CADASIL were tested for the presence of an RLS by means of contrast-enhanced transcranial Doppler (TCD). The diagnosis of migraine was made according to the 2004 International Headache Classification. Results: Sixteen CADASIL patients were tested; 6 had MA. Four patients displayed an RLS on contrast-enhanced TCD examination. Three of these patients had MA. Both patients with Arg141Cys displayed a large RLS. Conclusion: We conclude that RLS is not necessarily linked to CADASIL as a comorbidity factor. Nevertheless, there could be a relation between RLS and specific Notch3 mutations, such as Arg141Cys.

Donepezil in patients with subcortical vascular cognitive impairment: a randomised double-blind trial in CADASIL

Cholinergic deficits might contribute to vascular cognitive impairment. Trials of cholinesterase inhibitors in patients with vascular dementia are difficult because of heterogeneous disease mechanisms and overlap between vascular and Alzheimer's disease (AD) pathology in the age-group recruited. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is a genetic form of subcortical ischaemic vascular dementia. It represents a homogeneous disease process, and because of CADASIL's early onset, comorbid AD pathology is rare. We did a multicentre, 18-week, placebo-controlled, double-blind, randomised parallel-group trial to determine whether the cholinesterase inhibitor donepezil improves cognition in patients with CADASIL. 168 patients with CADASIL (mean age 54.8 years) were assigned to 10 mg donepezil per day (n=86) or placebo (n=82) by a computer-generated randomisation protocol. Inclusion criteria included a mini-mental state examination (MMSE) score of 10-27 or a trail making test (TMT) B time score at least 1.5 SD below the mean, after adjustment for age and education. The primary endpoint was change from baseline in the score on the vascular AD assessment scale cognitive subscale (V-ADAS-cog) at 18 weeks. Secondary endpoints included scores on the ADAS-cog, MMSE, TMT A time and B time, Stroop, executive interview-25 (EXIT25), CLOX, disability assessment for dementia, and sum of boxes of the clinical dementia rating scale. Analysis was done by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00103948. 161 patients were analysed. There was no significant difference between donepezil (n=84) and placebo (n=77) in the primary endpoint. The least-squares mean change from baseline score was -0.81 (SE 0.59) in the placebo group and -0.85 (SE 0.57) in the donepezil group (p=0.956). There was a significant treatment effect favouring donepezil on the following secondary outcomes: TMT B time (p=0.023), TMT A time (p=0.015), and EXIT25 (p=0.022). Ten donepezil-treated patients discontinued treatment due to adverse events compared to seven placebo-treated patients. Donepezil had no effect on the primary endpoint, the V-ADAS-cog score in CADASIL patients with cognitive impairment. Improvements were noted on several measures of executive function, but the clinical relevance of these findings is not clear. Our findings may have implications for future trial design in subcortical vascular cognitive impairment.

Reduction of optic nerve fiber layer thickness in CADASIL

Our study aims to assess nerve fiber layer (NFL) thickness in patients affected by cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL). Six CADASIL patients (mean age 42 +/- 16 years, best corrected visual acuity >20/20 with refractive error between +/-3 diopters, intraocular pressure <18 mmHg) were enrolled. They were compared with 16 age-matched controls. In all subjects enrolled, NFL thickness was measured by optical coherence tomography (OCT). Three different measurements were taken in each quadrant (superior, inferior, nasal, and temporal) and averaged. The data from all quadrants (12 values averaged) were identified as NFL overall. In CADASIL eyes there was a reduction of NFL thickness in each quadrant and in the NFL overall evaluation compared with the values observed in control eyes. Our results suggest that in CADASIL patients there is a reduction of NFL thickness evaluated by OCT. This morphological abnormality could be ascribed to an impairment of the retinal vascular supply leading to a global neuroretinal involvement. These anatomical changes may precede the onset of the neurological clinical manifestations.

Blood pressure and haemoglobin A1c are associated with microhaemorrhage in CADASIL: a two-centre cohort study

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is a hereditary arteriopathy caused by mutations of the Notch3 gene. The risk factors for cerebral microhaemorrhages (CM), their relationship to other MRI lesions in the disease and their potential clinical impact have not been previously defined. Our purpose was to examine the frequency, number and location of microhaemorrhages in a multicentre cohort study, defining predisposing factors and associated radiographic markers in CADASIL patients. We collected clinical data from 147 consecutive patients enrolled in an ongoing prospective cohort study. Degree of neurological disability and cognitive impairment were assessed by standardized scales. T(1)-weighted, FLAIR and T2*-weighted gradient-echo (GE) MRI sequences were performed. Volume and location of lacunar infarcts and white matter hyperintensity (WMH) were assessed. Number and location of CM were recorded. CM were present in 35% patients, most commonly occurring in the thalamus, brainstem and basal ganglia. The location of CM qualitatively differed from areas of lacunar infarction and WMH. There was a significant association between the presence of CM and a history of hypertension (P = 0.005), systolic blood pressure (SBP) (P = 0.014), haemoglobin A1c (HbA1c) (P = 0.004) and the volume of lacunar infarcts (P = 0.010) and WMHs (P = 0.046). The number of CM was independently associated with SBP (P = 0.005), the diagnosis of hypertension (P = 0.0004), volume of WMH (P = 0.0005) and lacunar infarcts (P = 0.004). In contrast, no association was found between blood pressure or HbA1c and the load of WMH or lacunar infarcts. The presence of CM was independently associated with increased modified Rankin scores. CM are independently associated with blood pressure and HbA1c as well as with lacunar infarct and WMH volume in CADASIL. Both the vascular risk factors and regional distribution of CM appear distinct from those associated with other MRI markers, suggesting a distinct pathological process. These lesions have a potential clinical impact in CADASIL. These findings further suggest that modulation of blood pressure and glucose levels might influence the course of the disease.

Is inadequate family history a barrier to diagnosis in CADASIL?

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) has typical clinical features that include stroke, migraine, mood disturbances and cognitive decline. However, misdiagnosis is common. We hypothesized that family history is poorly elicited in individuals presenting with features of CADASIL and that enquiry into family history of all four cardinal manifestations of CADASIL is superior to elicitation of family history of premature stroke alone in raising the diagnostic possibility of CADASIL. Retrospective review of family histories at presentation in 40 individuals with confirmed CADASIL was performed through structured interview in a Neurovascular Genetics clinic (182 first-degree and 242 second-degree relatives identified). Family history obtained from structured interview was compared to family history initially documented at presentation. At initial presentation, 30% of individuals were inaccurately documented to have no family history of significant neurological illness. Thirty-five per cent of patients had an initial alternative diagnosis. Initial inaccurate documentation of negative family history was more frequent in individuals with an initial alternative diagnosis. After structured interviews, 34% of 182 first-degree and 35% of 242 second-degree relatives of CADASIL patients had history of stroke (16% of first-degree relatives had stroke before the age of 50 years). Forty-three per cent of first-degree and 28% of second-degree relatives had migraine, mood disturbance or cognitive decline. A false-negative family history was commonly documented in individuals presenting with features of CADASIL and was associated with initial misdiagnosis. Restriction of family history to premature stroke alone is probably inadequate to identify affected CADASIL pedigrees.

Peripheral neuropathy in CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is a hereditary cerebral microangiopathy associated with mutations in the Notch 3 gene. The clinical phenotype is characterized by cerebral impairment even though typical microvascular changes are diffuse. To assess peripheral neuropathy in patients with CADASIL. We enrolled eleven CADASIL patients with variable phenotype including clinical signs of peripheral nerve involvement. In all patients electromyography and nerve conduction velocities were performed. Peripheral nerve biopsy was performed in three cases. We found sensory motor neuropathy in 7/11 patients. Nerve biopsy revealed axonal and demyelinated findings. Our findings suggest that peripheral neuropathy may be part of the CADASIL phenotype.

Skin biopsy immunostaining with a Notch3 monoclonal antibody for CADASIL diagnosis

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy) is a small-artery disease of the brain caused by NOTCH3 mutations that lead to an abnormal accumulation of NOTCH3 within the vasculature. We aimed to establish whether immunostaining skin biopsy samples with a monoclonal antibody specific for NOTCH3 could form the basis of a reliable and easy diagnostic test. We compared the sensitivity and specificity of this method in two groups of patients suspected of having CADASIL with complete scanning of mutation-causing exons of NOTCH3 (in a retrospective series of 39 patients) and with limited scanning of four exons that are mutation hotspots (prospective series of 42 patients). In the retrospective series skin biopsy was positive in 21 (96%) of the 22 CADASIL patients examined and negative in all others; in the prospective series, seven of the 42 patients had a positive skin biopsy whereas only four had a mutation detected by limited NOTCH3 scanning. Our immunostaining technique is highly sensitive (96%) and specific (100%) for diagnosis of CADASIL.

Update of pharmacologic management of behavioral disturbances in Alzheimer's disease

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy) is commonly overlooked or misdiagnosed owing to its recent identification and its variable mode of presentation. The defective gene in CADASIL is Notch3, which encodes a large transmembrane receptor. To set up a diagnostic test and to delineate the NotchS domains involved in CADASIL, we undertook mutations analysis in this gene in a group of CADASIL patients.50 unrelated patients with CADASIL and 100 healthy controls were screened for mutations along the entire Notch3 sequence, by means of single-strand conformation polymorphism, heteroduplex, and sequence analysis.Strongly stereotyped mis-sense mutations, located within the epidermal-growth-factor-like (EGF-like) repeats, in the extracellular domain of Notch3, were detected in 45 patients. Clustering of mutations within the two exons encoding the first five EGF-like repeats was observed (32 patients). All these mutations lead to loss or gain of a cysteine residue and therefore to an unpaired number of cysteine residues within a given EGF domain. None of these mutations was found in the 100 controls.Because of the strong clustering and highly stereotyped nature of the pathogenetic mutations detected in CADASIL patients, an easy and reliable diagnostic test for CADASIL is feasible. The findings suggest that aberrant dimerisation of NotchS, due to abnormal disulphide bridging with another NotchS molecule or with another protein, may be involved in the pathogenesis of this disorder.

Endothelial changes in muscle and skin biopsies in patients with CADASIL.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is characterized by the deposition of granular osmiophilic material in association with vascular smooth muscle cells in many different organs. However, the cause of the subsequent destruction of smooth muscle cells that are surrounded by granular osmiophilic material is unclear. In the present study, the ultrastructural changes that occur in endothelial cells in CADASIL have been evaluated by examining blood vessels in six skin biopsies and seven muscle biopsies belonging to three different CADASIL pedigrees. The appearances have been compared with five skin biopsies and five muscle biopsies from age-matched controls without vascular disease. The most striking features observed in vessels in the skin of CADASIL patients were attenuation of endothelial cells and increased density of endothelial cytoplasm, accompanied by the presence of compact bundles of microfilaments within the cytoplasm of endothelial cells. Endothelial cells in muscle biopsies from CADASIL patients, on the other hand, were swollen until destruction of tight junctions were observed. These findings suggest that impaired permeability of vascular endothelium may play a role in the destruction of vascular smooth muscle cells in CADASIL. Furthermore, the results of this study suggest that further fine structural investigation of blood vessel endothelium and underlying smooth muscle may lead to a better understanding of the pathophysiology of CADASIL.

Strong clustering and stereotyped nature of Notch3 mutations in CADASIL patients

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy) is commonly overlooked or misdiagnosed owing to its recent identification and its variable mode of presentation. The defective gene in CADASIL is Notch3, which encodes a large transmembrane receptor. To set up a diagnostic test and to delineate the Notch3 domains involved in CADASIL., we undertook mutations analysis in this gene in a group of CADASIL patients. 50 unrelated patients with CADASIL and 100 healthy controls were screened for mutations along the entire Notch3 sequence, by means of single-strand conformation polymorphism, heteroduplex, and sequence analysis. Strongly stereotyped mis-sense mutations, located within the epidermal-growth-factor-like (EGF-like) repeats, in the extracellular domain of Notch3, were detected in 45 patients. Clustering of mutations within the two exons encoding the first five EGF-like repeats was observed (32 patients). All these mutations lead to loss or gain of a cysteine residue and therefore to an unpaired number of cysteine residues within a given EGF domain. None of these mutations was found in the 100 controls. Because of the strong clustering and highly stereotyped nature of the pathogenetic mutations detected in CADASIL patients, and easy and reliable diagnostic test for CADASIL is feasible. The findings suggest that aberrant dimerisation of Notch3, due to abnormal disulphide bridging with another Notch3 molecule or with another protein, may be involved in the pathogenesis of this disorder.