Brain stem MRI signal abnormalities in CADASIL

Amyloid pathology and vascular risk are associated with distinct patterns of cerebral white matter hyperintensities: A multicenter study in 3132 memory clinic patients

INTRODUCTION

White matter hyperintensities (WMH) are associated with key dementia etiologies, in particular arteriolosclerosis and amyloid pathology. We aimed to identify WMH locations associated with vascular risk or cerebral amyloid-β1-42 (Aβ42)-positive status.

METHODS

Individual patient data (n = 3,132; mean age 71.5 ± 9 years; 49.3% female) from 11 memory clinic cohorts were harmonized. WMH volumes in 28 regions were related to a vascular risk compound score (VRCS) and Aß42 status (based on cerebrospinal fluid or amyloid positron emission tomography), correcting for age, sex, study site, and total WMH volume.

RESULTS

VRCS was associated with WMH in anterior/superior corona radiata (B = 0.034/0.038, p < 0.001), external capsule (B = 0.052, p < 0.001), and middle cerebellar peduncle (B = 0.067, p < 0.001), and Aß42-positive status with WMH in posterior thalamic radiation (B = 0.097, p < 0.001) and splenium (B = 0.103, p < 0.001).

DISCUSSION

Vascular risk factors and Aß42 pathology have distinct signature WMH patterns. This regional vulnerability may incite future studies into how arteriolosclerosis and Aß42 pathology affect the brain's white matter.

HIGHLIGHTS

Key dementia etiologies may be associated with specific patterns of white matter hyperintensities (WMH). We related WMH locations to vascular risk and cerebral Aβ42 status in 11 memory clinic cohorts. Aβ42 positive status was associated with posterior WMH in splenium and posterior thalamic radiation. Vascular risk was associated with anterior and infratentorial WMH. Amyloid pathology and vascular risk have distinct signature WMH patterns.

[Neuroimaging Characteristics of Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy (CADASIL) in Korean Based on Jeju Cohort: A Pictorial Essay]

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary small artery vasculopathy caused by mutations in the NOTCH3 gene on chromosome 19. Jeju Island has the highest reported prevalence of CADASIL patients in the world. Even though most studies on the neuroimaging characteristics of CADASIL have focused on Western populations, there are notable differences in Korean CADASIL patients compared to those in Western countries, which may impact their clinical manifestations and prognosis. Herein, this pictorial essay presents the neuroimaging patterns of CADASIL in patients in Korea, with an emphasis on the differences observed from previous reports based on a Western patient population.

Neuroimaging Pearls from the MDS Congress Video Challenge. Part 1: Genetic Disorders

We selected several "imaging pearls" presented during the Movement Disorder Society (MDS) Video Challenge for this review. While the event, as implicated by its name, was video-centered, we would like to emphasize the important role of imaging in making the correct diagnosis. We divided this anthology into two parts: genetic and acquired disorders. Genetic cases described herein were organized by the inheritance pattern and the focus was put on the imaging findings and differential diagnoses. Despite the overlapping phenotypes, certain described disorders have pathognomonic MRI brain findings that would provide either the "spot" diagnosis or result in further investigations leading to the diagnosis. Despite this, the diagnosis is often challenging with a broad differential diagnosis, and hallmark findings may be present for only a limited time.

CADASIL in Greece: Mutational spectrum and clinical characteristics based on a systematic review and pooled analysis of published cases

BACKGROUND

Differences have been noted in the clinical presentation and mutational spectrum of CADASIL among various geographical areas. The aim of the present study was to investigate the mode of clinical presentation and genetic mutations reported in Greece.

METHODS

After a systematic literature search, we performed a pooled analysis of all published CADASIL cases from Greece.

RESULTS

We identified 14 studies that reported data from 14 families comprising 54 patients. Migraine with aura was reported in 39%, ischemic cerebrovascular diseases in 68%, behavioral-psychiatric symptoms in 47% and cognitive decline in 60% of the patients. The mean (±SD) age of onset for migraine with aura, ischemic cerebrovascular diseases, behavioral-psychiatric symptoms and cognitive decline was 26.2 ± 8.7, 49.3 ± 14.6, 47.9 ± 9.4 and 42.9 ± 10.3, respectively; the mean age at disease onset and death was 34.6 ± 12.1 and 60.2 ± 11.2 years. With respect to reported mutations, mutations in exon 4 were the most frequently reported (61.5% of all families), with the R169C mutation being the most common (30.8% of all families and 50% of exon 4 mutations), followed by R182C mutation (15.4% of all families and 25% of exon 4 mutations).

CONCLUSIONS

The clinical presentation of CADASIL in Greece is in accordance with the phenotype encountered in Caucasian populations, but differs from the Asian phenotype, which is characterized by a lower prevalence of migraine and psychiatric symptoms. The genotype of Greek CADASIL pedigrees is similar to that of British pedigrees, exhibiting a high prevalence of exon 4 mutations, but differs from Italian and Asian populations, where mutations in exon 11 are frequently encountered.

An alternative mechanism of crossed vertical gaze palsy in unilateral mesodiencephalic infarction

Crossed vertical gaze palsy refers to a rare combination of elevation paresis in one eye and depression palsy in the fellow eye. It was once reported in a patient with unilateral infarction involving the mesodiencephalic junction, and was ascribed to selective disruption of the fibers projecting from the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) to the oculomotor nuclear complex. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a rare cause of ophthalmoplegia and crossed vertical gaze palsy has not been described in this disorder. Our patient with a circumscribed acute infarction involving the left mesodiencephalic junction due to CADASIL showed both upward and downward gaze palsy in both eyes, but more marked depression paresis in the ipsilesional eye and more conspicuous elevation deficit in the contralesional eye, which was consistent with crossed vertical gaze palsy. We provide alternate explanation for this rare phenotype of vertical gaze palsy. Selective disruption of riMLF fibers may cause crossed vertical gaze palsy in unilateral mesodiencephalic lesion.

Is the time ripe for new diagnostic criteria of cognitive impairment due to cerebrovascular disease? Consensus report of the International Congress on Vascular Dementia working group

BACKGROUND

Long before Alzheimer's disease was established as the leading cause of dementia in old age, cerebrovascular lesions were known to cause cognitive deterioration and associated disability. Since the middle of the last century, different diagnostic concepts for vascular dementia and related syndromes were put forward, yet no widely accepted diagnostic consensus exists to date.

DISCUSSION

Several international efforts, reviewed herein, are ongoing to define cognitive impairment due to cerebrovascular disease in its different stages and subtypes. The role of biomarkers is also being discussed, including cerebrospinal fluid proteins, structural and functional brain imaging, and genetic markers. The influence of risk factors, such as diet, exercise and different comorbidities, is emphasised by population-based research, and lifestyle changes are considered for the treatment and prevention of dementia.

CONCLUSION

To improve the diagnosis and management of vascular cognitive impairment, further progress has to be made in understanding the relevant pathomechanisms, including shared mechanisms with Alzheimer's disease; bringing together fragmented research initiatives in coordinated international programs; testing if known risk factors are modifiable in prospective interventional studies; and defining the pre-dementia and pre-clinical stages in line with the concept of mild cognitive impairment due to Alzheimer's disease.

Characterisation of endothelin-1-induced intrastriatal lesions within the juvenile and adult rat brain using MRI and 31P MRS

Improved non-invasive magnetic resonance (MR) characterisation of in vivo models of focal ischaemic insults such as transient ischaemic attack (TIA) and perinatal arterial ischaemic stroke (AIS) may assist diagnosis, outcome prediction and treatment design. The classic middle cerebral artery occlusion (MCAO) model of ischaemic stroke is well documented in MR studies but generates extensive and complex lesions involving an acute inflammatory response and de-occlusion that immediately restores circulation. By contrast, intrastriatal microinjection of the potent vasoconstrictor, endothelin-1 (ET-1), induces a focal, reversible and low-flow ischaemia in the absence of a typical inflammatory response, which gradually restores blood flow over several hours and may be more relevant to TIA and AIS pathology. This study presents the first comprehensive longitudinal MR characterisation of the real-time anatomical [T1-weighted (T1-w)/T2-weighted (T2-w)], pathophysiological [apparent diffusion coefficient (ADC), cerebral blood volume, gadolinium contrast imaging of blood-brain barrier (BBB) integrity] and metabolic [phosphorus magnetic resonance spectroscopy (31P MRS)] evolution of a purely ischaemic ET-1-induced lesion within the juvenile and adult rat brain. ET-1-induced cytotoxic oedema was visualised on T2-w magnetic resonance imaging (MRI), inconsistent with the conventional notion that it cannot be detected using anatomical MRI. There was no immunohistochemical evidence of an acute inflammatory response or loss of BBB integrity, thus excluding a vasogenic oedema contribution to the pathology. Maximal T2-w intensity correlated with the lowest ADC value in both age groups, re-emphasising the purely ischaemic nature of the lesion and the absence of vasogenic oedema. Furthermore, extensive acute T1-w hypointensity was observed in the presence of cytotoxic oedema-induced T2-w changes, whereas other authors have shown that increased T1 values following MCAO reflect vasogenic oedema. Intriguingly, the lesion border exhibited hyperintensity on T2-w and ADC MRI at later time points, and the former may be a consequence of phagocytosis-induced fatty droplet deposition by macrophages detected immunohistochemically. In spite of a chronically reduced ADC, typically associated with ischaemia-induced energy failure, a 31P MRS-detectable reduction in the phosphocreatine (PCr) to gamma adenosine triphosphate (γATP) ratio was not observed at any time point in either age group, suggesting dissociation of tissue water diffusion and metabolic changes within the ET-1-induced lesion.

Depressive symptoms in late life and cerebrovascular disease: the importance of intelligence and lesion location

BACKGROUND

The influence of white matter lesions on depressive symptoms in healthy ageing populations remains unclear. In this study, we examined the relationship between depressive symptoms and magnetic resonance imaging (MRI) detected cerebrovascular disease in a normal population living independently in the community, and measured the influence of location of brain abnormalities, fluid intelligence, living alone, and sex.

METHODS

Prospective cohort: 497 community dwelling individuals all born in 1936, who took part in the Scottish Mental Survey of 1947, were followed up in 2000 and at biannual intervals in a longitudinal study of health and cognitive aging. Two hundred forty-four volunteered for brain MRI in 2004-2006. Suitable data were available in 219/244, of whom 115 were men. Brain hyperintensities in lobar white matter, basal ganglia , periventricular, and infratentorial regions were measured using Scheltens' scale. Depressed mood was assessed using the Hospital Anxiety and Depression Scale (HADS) on three biannual intervals. Relationships between Scheltens' scores, HADS-D scores, fluid intelligence, living alone, and sex were assessed using general linear modeling.

RESULTS

The main predictor of depressive symptom scores was poorer fluid intelligence (partial η(2) =0.023-0.028, P < .05). Ischemic change in the brainstem (partial η(2) = 0.026, P ≤.05) and basal ganglia (partial η(2) =0.018, P ≤ .05) also predicted HADS-D scores. There was no relationship with sex or living alone.

CONCLUSIONS

Hyperintensities in the brainstem and basal ganglia are associated with depressive symptoms. Higher fluid intelligence is associated with lower depressive symptoms in this normal, ageing population.

Acetazolamide for the prophylaxis of migraine in CADASIL: a preliminary experience

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited microangiopathy caused by NOTCH3 mutations. It is characterized by migraine, with or without aura, ischemic events, psychiatric and cognitive disturbances. There is no approved treatment for migraine prophylaxis in CADASIL, but acetazolamide has been anecdotally reported to be effective. We retrospectively reviewed our database of patients with a genetic diagnosis of CADASIL to identify how many of them were treated with acetazolamide for the prophylaxis of migraine. The efficacy and the tolerability of this treatment were checked looking at the clinic reports. Acetazolamide was prescribed in seven patients; the mean duration of treatment was 6 months, and the daily dose ranged from 125 to 500 mg. Three patients had a total and sustained remission, while in two patients a reduction in attacks and an improvement of the headache intensity were recorded. In one of these, acetazolamide was deliberately taken only during the migraine attack and the beneficial effect started 1 h after administration. In two patients, the drug did not produce any beneficial effect. Mild side effects were recorded in two patients. Our preliminary experience expands previous reports and confirms the possible efficacy of acetazolamide in CADASIL migraine. Based on these data, a randomized controlled trial seems worthy to be carried out to test the efficacy and safety of this drug.

Magnetic resonance imaging in cerebral small vessel disease and its use as a surrogate disease marker

Cerebral small vessel disease is an important cause of vascular cognitive impairment and dementia. On brain imaging, discrete lacunar infarcts and/or more diffuse regions of white matter hyperintensities or leucoaraiosis are seen. Magnetic resonance imaging plays a crucial role in diagnosis, and advanced magnetic resonance imaging techniques are providing new information on disease mechanisms and offering potential as surrogate disease markers. Longitudinal studies have demonstrated detectable progression of lesion load over short time periods, and weak correlations with cognition. Stronger correlations with cognition have been found with diffusion tensor imaging, which is more sensitive to white matter tract structure, supporting a role for disconnection in the pathogenesis of cognitive impairment. Brain volume also consistently correlates with cognition in asymptomatic small vessel disease, sporadic small vessel disease, and Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy. Gradient echo magnetic resonance imaging identifies microbleeds in a significant proportion of patients with small vessel disease, although their role in clinical management remains to be determined. Surrogate markers to monitor disease progression and evaluate new therapies would have major clinical use. The greater sensitivity of diffusion tensor imaging parameters and brain volume to change, and the stronger correlation of these parameters with cognition, suggest that they may be more powerful surrogates. However, data from longitudinal and intervention studies are required to determine if this is indeed the case. In this systematic review, we describe the use of both conventional and advanced magnetic resonance imaging techniques in patient groups with the full spectrum of clinical small vessel disease, from normal populations with WMH to patients groups with lacunar stroke and dementia.

Migraine is associated with an increased risk of deep white matter lesions, subclinical posterior circulation infarcts and brain iron accumulation: the population-based MRI CAMERA study

Previous studies have suggested that migraine is a risk factor for brain lesions, but methodological issues hampered drawing definite conclusions. Therefore, we initiated the magnetic resonance imaging (MRI) ‘CAMERA’ (Cerebral Abnormalities in Migraine, an Epidemiological Risk Analysis) study. We summarize our previously published results. A total of 295 migraineurs and 140 controls were randomly selected from a previously diagnosed population-based sample (n = 6039), who underwent an interview, physical examination and a brain MRI scan. Migraineurs, notably those with aura, had higher prevalence of subclinical infarcts in the posterior circulation [odds ratio (OR) 13.7; 95% confidence interval (CI) 1.7, 112]. Female migraineurs were at independent increased risk of white matter lesions (WMLs; OR 2.1; 95% CI 1.0, 4.1), and migraineurs had a higher prevalence of brainstem hyperintense lesions (4.4% vs. 0.7%, P = 0.04). We observed a higher lifetime prevalence of (frequent) syncope and orthostatic insufficiency in migraineurs; future research needs to clarify whether autonomic nervous system dysfunction could explain (part of) the increased risk of WMLs in female migraineurs. Finally, in migraineurs aged < 50 years, compared with controls, we found evidence of increased iron concentrations in putamen (P = 0.02), globus pallidus (P = 0.03) and red nucleus (P = 0.03). Higher risks in those with higher attack frequency or longer disease duration were found consistent with a causal relationship between migraine and lesions. This summary of our population-based data illustrates that migraine is associated with a significantly increased risk of brain lesions. Longitudinal studies are needed to assess whether these lesions are progressive and have relevant (long-term) functional correlates.

CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a dominantly inherited small artery disease that leads to dementia and disability in mid-life. The clinical presentation of CADASIL is variable between and within affected families and is characterized by symptoms including migraine with aura, subcortical ischemic events, mood disturbances, apathy, and cognitive impairment. The mean age at onset of symptoms is 45 years, with variable duration of the disease ranging from 10 to 40 years. In 1996, linkage studies mapped and identified mutations in the NOTCH3 gene on chromosome 19 as causative in CADASIL. Head magnetic resonance imaging (MRI) is always abnormal in participants with NOTCH3 mutations after age 35. Magnetic resonance imaging shows on T2-weighted images or fluid attenuation inversion recovery (FLAIR) sequence, widespread areas of increased signal in the white matter associated with focal hyperintensities in basal ganglia, thalamus, and brainstem. The pathologic hallmark of CADASIL is the presence of electron-dense granules in the media of arterioles that can be identified by electron microscopic evaluation of skin biopsies.

Genetically confirmed CADASIL in a pediatric patient

A 17-year-old girl presented with migraine with prolonged aura and aura without headache. Neurologic examination was normal. Her mother, who did not have a history of migraine, developed right-face and -arm numbness at the age of 45. Evaluation revealed white matter changes consistent with CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy), and genetic testing showed a Notch3 gene mutation consistent with CADASIL. Our patient's MRI revealed white matter changes and the same Notch3 gene mutation. Low-dose aspirin was started in an attempt to prevent stroke. CADASIL is considered a degenerative disease of adult onset that leads to progressive neurologic deterioration. Onset of symptoms is in the third decade. Migraine, one of its most common manifestations, can develop in childhood. Evaluation for secondary causes is warranted in select pediatric patients who present with atypical migraine, when there is a family history of CADASIL or atypical patterns such as aura without headache, or in the presence of white matter abnormalities. The pathophysiology of CADASIL is poorly understood, and there is no proven effective therapy. Patients require genetic counseling and close follow-up. It is not known if interventions such as antiplatelet therapy are beneficial if instituted early in the course of the disease. Screening of family members at risk for CADASIL, even in the pediatric population, should be considered and offered to patients with CADASIL and their families. CADASIL has rarely been described in the pediatric population. This case report expands our current understanding of the disorder in children.

Cadasil

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) is the most common heritable cause of stroke and vascular dementia in adults. Clinical and neuroimaging features resemble those of sporadic small-artery disease, although patients with CADASIL have an earlier age at onset of stroke events, an increased frequency of migraine with aura, and a slightly variable pattern of ischaemic white-matter lesions on brain MRI. NOTCH3 (Notch homolog 3), the gene involved in CADASIL, encodes a transmembrane receptor primarily expressed in systemic arterial smooth-muscle cells. Pathogenetic mutations alter the number of cysteine residues in the extracellular domain of NOTCH3, which accumulates in small arteries of affected individuals. Functional and imaging studies in cultured cells, genetically engineered mice, and patients with CADASIL have all provided insights into the molecular and vascular mechanisms underlying this disease. A recent multicentre trial in patients with cognitive impairment emphasises the feasibility of randomised trials in patients with CADASIL. In this Review, we summarise the current understanding of CADASIL, a devastating disorder that also serves as a model for the more common forms of subcortical ischaemic strokes and pure vascular dementia.

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited autosomal dominant condition characterized by migrane, recurrent stroke, subcortical dementia, and pseudobulbar palsy. It begins with migraine with aura in -33% of patients. CADASIL is commonly overlooked or misdiagnosed owing to its recent identification. The pathological hallmark of angiopathy is the presence of multiple, small, deep cerebral infarcts, leucoencephalopathy, and nonatherorosclerotic, nonamyloid angiopathy involving mainly small, deep perforating cerebral arteries. Changes also are present in vascular smooth muscle cells and consist in the presence of granular osmiophilic material (GOM). The defective gene in CADASIL is Notch 3, which encodes a large transmembrane receptor. Magnetic resonance imaging shows high intensity signal lesions, often confluent, and areas of cystic degeneration of subcortical white matter and basal ganglia. Diagnostic strategies in CADASIL are matter of discussions because the electron microscopic demonstration of GOM was reported in 100% of symptomatic patients of French authors, but only in 45% of a British study. GOMs are not present in presymptomatic patients.

Neuropsychiatric manifestations in CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited small-artery disease of mid-adulthood caused by mutations of the NOTCH3 gene. The disease is responsible for widespread white-matter lesions associated with lacunar infarctions in various subcortical areas. The disease is responsible for migraine with aura and ischemic strokes, and is associated with various degrees of cognitive impairment and with mood disturbances. CADASIL is considered as a unique model to investigate what is known as "subcortical ischemic vascular dementia." Recent data suggest that the number of lacunar infarctions and severity of cerebral atrophy are the main magnetic resonance imaging markers associated with cognitive and motor disabilities in this disorder. Mood disturbances are reported in 10% to 20% of patients, most often in association with cognitive alterations. Their exact origin remains unknown; the presence of ischemic lesions within the basal ganglia or the frontal white matter may promote the occurrence of these symptoms. Further studies are needed to better understand the relationships between cerebral lesions and both cognitive and psychiatric symptoms in this small-vessel disease of the brain.

Formes pauci symptomatiques de CADASIL après 60 ans

INTRODUCTION

CADASIL is a hereditary cerebral arteriopathy leading to progressive disability and dementia usually observed at 60 years.

OBSERVATION

We report four patients aged>60 years with typical Notch3 mutations leading to CADASIL who did not have dementia or disability. Three of them presented with only transient neurological manifestations. MRI results showed extensive hyperintense signals in the white-matter on T2-weighted images contrasting with very few lacunar infarcts.

CONCLUSION

These observations suggest that silent or symptomatic infarcts, which were rare in the present cases may be responsible for the clinical severity in this disorder.

Single gene disorders causing ischaemic stroke

Stroke is the third most common cause of death and the leading cause of long-term neurological disability in the world. Conventional vascular risk factors for stroke contribute approximately to only forty to fifty percent of stroke risk. Genetic factors may therefore contribute to a significant proportion of stroke and may be polygenic, monogenic or multi-factorial. Monogenic (single gene) disorders may potentially account for approximately one percent of all ischaemic stroke. Monogenic stroke disorders include conditions such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) and hereditary endotheliopathy, retinopathy, nephropathy and stroke (HERNS). In addition, other monogenic conditions such as sickle cell and Fabry disease also lead to stroke. These monogenic disorders cause either small vessel or large vessel stroke (or a combination of both) and serve as useful models for understanding and studying conventional stroke and cerebrovascular disease and its accompaniments such as vascular dementia.

A chemical shift imaging study on regional metabolite distribution in a CADASIL family

A chemical shift imaging (CSI) study was performed to directly assess relative concentrations of N-acetylaspartate (NAA), Cho and Cr metabolites in normal- and abnormal-appearing brain tissue of asymptomatic and symptomatic members of a single family with a neuropathologic, genetic and electrophysiological confirmed diagnosis of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy. The aim of the investigation was to evaluate clinical findings and metabolite abnormalities as early appearance of axonal injury in this syndrome. The main findings related statistically significant decreases in the mean metabolite ratios for NAA/Cr, NAA/Cho and Cho/Cr in the anterior parts in comparison with the posterior parts of the centrum semiovale in symptomatic and asymptomatic patients. The effect was considerably greater in the symptomatic patients, indicating a strong correlation between CSI and pathology results. No differences were found between the two areas in the control group. Although lactate signals were hardly detectable in individual spectra, there was a trend toward increased Lac/Cr values in the anterior parts with respect to the posterior parts in the patient group, with the effect particularly evident in the asymptomatic subjects with the gene mutation.

Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephaloapthy (CADASIL)

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is an inherited cerebrovascular disease characterized by recurrent subcortical ischemic strokes starting in the third or fourth decade as a result of mutations in the Notch3 gene. Granular osmiophilic material (GOM) deposition around the vascular smooth muscle cells is a specific feature and electron microscopic observations of skin biopsies are useful for this diagnosis. A 39-year-old female with dizziness, abnormal visual fields, and hemiplegia, and a 42-year-old male with tinnitus and dizziness, were suspected of suffering from CADASIL based on MRI findings. Both cases were shown to have characteristic deposits of GOM, 200 to 800 nm in diameter, around the vascular smooth muscle cells of small arteries in the deep dermis, and thus the diagnoses of CADASIL were made, although there was no family history of cerebrovascular disorders or dementia. Dermatologists should be aware of these ultra-structural findings because this disease may occur sporadically and might be more common than initially thought.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) in a Chinese family: clinical, radiological and skin biopsy features

We describe the clinical, radiological, genetic and skin biopsy findings of the first Chinese family with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Of the 43-member family tree extending over three generations, eight had typical clinical features of CADASIL with recurrent ischemic stroke. In the three surviving affected family members, brain MRI showed extensive leukoaraiosis. Genotyping revealed heterozygous C to T mutation at nucleotide 406 in exon 3. Unusual clinical features were cerebellar infarction as a presenting complaint and a late age of onset with mild symptoms at age 69. A novel finding is the suggestion of a direct correlation between clinical disease severity and the quantity of ultrastructural pathognomonic granular osmophilic material (GOM) seen on skin biopsy.

Lessons from CADASIL

Vascular dementia (VaD) includes several different vascular mechanisms and changes in the brain. Among VaD, CADASIL is an inherited angiopathy caused by mutations in the Notch3 gene. The pathological hallmark of CADASIL is a granular osmiophilic material deposit (GOM) that is not only found in the brain, but also in the peripheral vascular tree. Consequently, a window into the brain was opened from a strictly neurological disease with tremendous consequences thanks to a skin biopsy. The latter was and continues to be used as a diagnostic tool for CADASIL, despite an immunohistochemical test that is now available. The skin biopsy first used as a diagnostic tool revealed the existence of numerous other VaDs presenting systemic vascular changes. Later, skin biopsy became a research tool, and a morphological skin vessel change classification was proposed on 300 patients. Interestingly, similar skin vessel lesions appear to be related to the same biological modifications. In addition, an early destruction of the medial muscle cells was noticed in 74% of cases. Because vascular smooth muscle cells secrete a powerful endothelial permeability factor (VEGF), their destruction could lead to a decrease in vascular permeability. Cocultures of endothelial cells with vascular muscle cells showed that their presence doubled vascular permeability. Thus, alteration or the loss of vascular muscle cells likely results in hypopermeability, in addition to vessel wall hypotonia and a watershed hypoperfusion. The wealth of information brought forth by knowledge of CADASIL provided new tools for research and clues for understanding the consequences of vascular impairments in dementia.

Nocturnal blood pressure dip in CADASIL

The influence of a nocturnal blood pressure dip on cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) has not yet been clarified. We attempted to examine a correlation with the nocturnal blood pressure dip and CADASIL. We monitored circadian blood pressure patterns by the use of a portable blood pressure monitoring device in five patients with CADASIL and 10 age- and sex-matched control subjects. Based on nocturnal fall in mean arterial blood pressure (MABP), we classified patients into extreme dippers (nocturnal reduction of MABP > or =20%), dippers (> or =10% but <20%), nondippers (<10% but > or =0%), and inverted dippers (<0%). Three patients revealed non-dipper and two inverted dipper. Nighttime MABP fall was significantly lower in patients compared with control subjects (P<0.01). This study suggests that a lower nocturnal blood pressure fall may be partly associated with incidence and/or worsening of deep white matter lesions in CADASIL.

Distribution of cranial MRI abnormalities in patients with symptomatic and subclinical CADASIL

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a rare, inherited cause of early stroke and dementia, with a poor prognosis. This study was performed to clarify lesion appearance and pattern of lesion distribution in CADASIL. 20 members of a single family were tested for the CADASIL gene mutation and studied with cranial MRI. Scans were evaluated for lesion load and pattern of lesion distribution. 19 patients had cranial MRI, of whom 11 had normal MRI scans, were clinically unaffected and tested negative for the CADASIL gene mutation. The remaining eight patients had abnormal cranial MRI scans: seven patients were positive for the CADASIL gene mutation and one (untested) patient was severely clinically affected. Three of the patients who tested positive for the CADASIL gene mutation were clinically unaffected at the time of imaging. All eight patients with abnormal cranial MRI had subcortical white matter abnormalities, mostly in frontal and temporal lobes. Lesions involving the corpus callosum were present on sagittal T2 weighted images in four of five clinically affected and one of three clinically unaffected patients. Lesions involving the deep grey nuclei and the brain stem were common. On T1 weighted images, lesions were either poorly defined (confluent white matter hypointensity) or well defined (cystic infarcts or enlarged perivascular spaces). Atrophy was infrequent. Familiarity with the range of cranial MRI appearances may aid diagnosis of CADASIL. Recognition of cranial imaging features in asymptomatic CADASIL patients could prompt earlier diagnosis.