A Chinese pedigree of cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL): Clinical and radiological features

Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is a rare hereditary cerebral vascular disease thought to be confined to Japan. This paper reports a Chinese pedigree of CARASIL in which two patients exhibited all of the typical clinical features of the disease. The radiological features are also discussed and compared with those of CADASIL. These cases illustrate the unique clinical and radiological features of CARASIL and challenge the idea that CARASIL is limited to the Japanese population.     

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”.     

Single gene disorders causing ischaemic stroke

Abstract 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.     

Histopathologic features of an autopsied patient with cerebral small vessel disease and a heterozygous HTRA1 mutation

Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is a hereditary cerebral small vessel disease (CSVD) caused by homozygous or compound heterozygous mutations of the high temperature requirement A serine peptidase 1 gene (HTRA1). Affected patients suffer from cognitive impairment, recurrent strokes, lumbago and alopecia. Recently, clinical studies have indicated that some patients with heterozygous mutations in HTRA1 may also suffer CSVD. Here, we report the histopathologic features of an autopsied 55‐year‐old male patient who had shown cognitive impairment and multiple cerebral infarcts, and was found to have a heterozygous missense mutation (p.R302Q) in the HTRA1 gene. Histologically, small vessels in the brain and spinal cord showed intimal proliferation, splitting of the internal elastic lamina, and degeneration of smooth muscle cells in the tunica media. Thus, although less severe, the features were quite similar to those of patients with CARASIL, indicating that patients with heterozygous mutations develop CSVD through underlying pathomechanisms similar to those of CARASIL.     

NOTCH3 mutation involving three cysteine residues in a family with typical CADASIL.

Mutations in NOTCH3 are the cause of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a hereditary angiopathy causing stroke and vascular dementia. All CADASIL mutations identified so far result in the loss or gain of one cysteine residue within epidermal growth factor (EGF)-like repeat domains. Here an in-frame deletion causing a loss of three cysteine residues within EGF repeat 6 is reported. These data are consistent with the hypothesis that the change toward an odd number of cysteine residues within a given EGF repeat and therefore an unpaired, reactive cysteine residue is the common and critical molecular event in CADASIL.     

Genotype–phenotype correlations of heterozygous HTRA1-related cerebral small vessel disease: case report and systematic review

neurogenetics - Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is caused by biallelic HTRA1 pathogenic variants. Recent studies have shown...     

常染色体显性遗传性脑动脉病伴皮层下梗死和白质脑病研究进展

常染色体显性遗传性脑动脉病伴皮层下梗死和白质脑病（Cerebral autosomal dominantarteriopathy with subcortical infarcts and leukoencephalopathy,CADASIL）是一种在成人时发病且以显性方式遗传的小动脉血管病变。它的临床特征主要为反复性的脑皮质下梗死及痴呆症,在少数的患者身上同时可见先兆性偏头痛及精神疾病方面的症状。它的致病基因是NOTCH3。CADASIL是最常见的因为单基因变异所造成的遗传性脑血管病变。该文简单介绍CADASIL的临床症状、分子遗传致病机制、诊断方法、在台湾的现况以及治疗与预防建议。     

Extensive loss of arterial medial smooth muscle cells and mural extracellular matrix in cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL)

Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is a distinctive clinicopathologic entity characterized by young adult‐onset non‐hypertensive vasculopathic encephalopathy accompanied by alopecia and disco‐vertebral degeneration. CARASIL arteriopathy is histopathologically characterized by intense arteriosclerosis without the deposition of granular osmiophilic materials. Until now, the obliterative arteriosclerosis is the presumptive cause of subcortical ischemia in CARASIL; however, a detailed vascular pathology leading to diffuse leukoencephalopathy remains unclear. In this study, we examined two autopsied CARASIL brains in comparison with an autopsy case of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Intensity of arterial sclerotic changes of CARASIL was evaluated by sclerotic index analysis. Immunohistochemical investigations were performed using a battery of primary antibodies, which recognized vascular cellular and extracellular components. As a result, sclerotic changes were disclosed to be mild and infrequent in CARASIL, in contrast to CADASIL that showed severe obliterative arterial changes. In CARASIL, conversely, most of the arteries were centrifugally enlarged and some were collapsed. We further revealed that arterial medial smooth muscle cells (SMCs) in patients with CARASIL were extensively lost, even in arteries without sclerotic changes. Arterial adventitia in CARASIL was conspicuously thin and immunoreactivities for type I, III, and VI collagens and fibronectin were appreciably weak in this region, indicating a reduction in the mural extracellular matrix (ECM). Because of the medial and adventitial degeneration, CARASIL brains likely receive marked fluctuations in blood flow because of deviations in the structural and functional basis of autoregulation mechanisms. We thus consider that diffuse leukoencephalopathy in CARASIL may be caused by arterial medial SMC loss with mural ECM reduction. We speculate that the abnormalities in the ECM are causatively related to the SMC degeneration, since the ECM is a crucial signal determining the biophysiological properties of arterial SMCs.     

Cerebral arterial pathology of CADASIL and CARASIL (Maeda syndrome)

Two familial cerebro‐vascular diseases characterized by different cerebral arterial pathologies and presenting in non‐hypertensive young and middle‐aged adults are described. Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is characterized by the deposition of smudged periodic acid–Schiff (PAS)‐positive granules known as granular osmiophilic materials (GOM) in the media of small arteries and arterioles. The medial smooth muscle cells are completely lost, and intense adventitial fibrosis is present. Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL), or Maeda syndrome, is characterized by intense arteriolosclerosis without GOM deposition. Fibrous intimal proliferation, hyaline degeneration of the media, thickening and splitting of the internal elastic lamina, and concentric narrowing of the lumen are characteristic features. In PAS preparation, small arteries are occasionally stained homogeneously due to exudative changes, but never exhibit granular appearance in CARASIL (Maeda syndrome). Each of the small arterial changes is intense in the cerebral medullary and leptomeningeal arteries, leading to multifocal, confluent, or diffuse ischemic changes in the cerebrum. The authors suggest that CARASIL be referred to as ‘Maeda syndrome’ or ‘CARASIL (Maeda syndrome)’ to avoid confusion with CADASIL.     

Report of a patient with CADASIL having a novel missense mutation of the Notch 3 gene--association with alopecia and lumbar herniated disk]

We report a 52-year-old man with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) presenting dementia, alopecia and lumbar herniated disk. He had an episode of stroke and migraine-like headache lasting for 5 minutes. A lot of members had cerebral infarction in this family. Brain magnetic resonance imaging demonstrated, on T2-weighted images, numerous hyperintense lesions suggestive of small infarcts in the basal ganglia and diffuse hyperintense lesions in the cerebral white matter. The clinical symptoms, the family history and the MRI findings suggested the diagnosis of CADASIL. However, the patient also showed alopecia and lumbar herniated disk, both are characteristic features of cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL). The DNA analysis of the Notch 3 gene identified a novel missense mutation Cys174Phe in this patient. Our case report indicated the importance of the DNA analysis for the diagnosis of CADASIL.     

Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL): A challenging diagnosis and a rare multiple sclerosis mimic

Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is an extremely rare hereditary cerebral small vessel disease caused by homozygous or compound heterozygous mutations in the gene coding for high-temperature requirement A serine peptidase 1 (HtrA1). Given the rare nature of the disease, delays in diagnosis and misdiagnosis are not uncommon. In this article, we reported the first case of CARASIL from Saudi Arabia with a novel homozygous variant c.1156C>T in exon 7 of the HTRA1 gene. The patient was initially misdiagnosed with primary progressive multiple sclerosis and treated with rituximab. CARASIL should be considered in the differential diagnosis of patients with suspected atypical progressive multiple sclerosis who have additional signs such as premature scalp alopecia and low back pain with diffuse white matter lesions in brain MRI. Genetic testing is important to confirm the diagnosis.     

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy syndrome mutations increase susceptibility to spreading depression

Migraine with aura is often the first manifestation of cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy syndrome (CADASIL), a disorder caused by NOTCH3 gene mutations expressed predominantly in vascular smooth muscle. Here, we report that cortical spreading depression (CSD), the electrophysiological substrate of migraine aura, is enhanced in mice expressing a vascular Notch 3 CADASIL mutation (R90C) or a Notch 3 knockout mutation. The phenotype was stronger in Notch 3 knockout mice, implicating both loss of function and neomorphic mutations in its pathogenesis. Our results link vascular smooth muscle Notch 3 mutations to enhanced spreading depression susceptibility, implicating the neurovascular unit in the development of migraine aura.     

A Case of Leukoencephalopathy and Small Vessels Disease Caused by a Novel HTRA1 Homozygous Mutation

Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) is a heritable, rare small vessel disease, which is caused by HTRA1 mutations and mostly reported Japanese and Chinese population. CARASIL is an orphan disease, which presents with progressive motor and cognitive impairment, alopecia, and spondylosis. The disease typically starts with lumbago at early twenties. Ischemic strokes start at mid-twenties. Patients have no cardiovascular or any other risk factors. Multiple lacunar infarcts and leukoencephalopathy cause progressive neurologic involvement. Leukoencephalopathy and small vessel disease without any risk factors is a significant finding for the differential diagnosis of HTRA1 gene pathology. This report presents clinical and genetic features of a rare case of typical CARASIL from Turkey who was followed with uncertain diagnoses for years.     

Young-adult-onset hereditary subcortical vascular dementia: cerebral autosomal recessive arteriosclerosis with subcortical infarcts and leukoencephalopathy (CARASIL)]

The clinical features of a probably autosomal recessive syndrome ("CARASIL"), yet to be confined in Japan and characterized by prematurity of vascular dementia, alopecia and spondylosis deformans are reviewed through comparison with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), which has been reported in Europe and North America, and recently in Japan. These two syndromes have many common features, such as familiality, encephalopathy of Binswanger type, and absence of vascular risk factors. There exists, however, a number of differences as follows: (1) Onset of encephalopathy is 32 years of age in "CARASIL" vs. 45 in CADASIL. (2) Male to female ratio is 3.2: 1 vs. 2:1.(3) Two thirds of "CARASIL" patients show stroke and/or stepwise deterioration, while almost all CADASIL patients have stroke. (4) Associated psychiatric features are euphoria, emotional lability and loss of spontaneity vs. severe mood disorders. (5) Migraine is a cardinal feature of CADASIL and vasospasm may occur during cerebral angiography. (6) White matter lesions on MRI are diffuse and homogeneous vs. punctuated and nodular. The latter four differences may mirror the difference in the pathology of arteriopathies. "CARASIL" is clearly different from CADASIL and reflect a second genetic condition with a seemingly direct effect upon the cerebral vasculature.     

Two Unique Mutations in HTRA1-Related Cerebral Small Vessel Disease in North America and Africa and Literature Review

ObjectiveTo describe and compare two cases of North American and African patients who were diagnosed with HTRA1-related cerebral small vessel disease (CSVD) with homozygous and heterozygous mutations, respectively, in the linker domain of the HTRA1 gene.Materials and methodsCase reports and literature review.ResultsA 49-year-old man from Mexico presented with recurrent lacunar strokes and memory loss. A 46-year-old woman from Eritrea presented with progressive memory loss. Neither patient had alopecia. MRI of the brain and spine in both patients showed leukoencephalopathy, microbleeds and spondylosis. Microbleeds along the subpial surfaces of the brainstem were only seen in the Mexican man. Genetic sequencing of HTRA1 gene revealed a novel homozygous mutation of p.A173S in the Mexican man supporting cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL). A heterozygous mutation of p.V175M was detected in the African woman, which has not been reported in patients of African ethnicity. In reviewing literature, CARASIL patients with mutation in the linker domain are older at neurological symptom onset and more frequently presented with stroke compared to patients with non-linker domain mutations. In patients of HTRA1-CSVD from heterozygous mutations, male is more common.ConclusionsHTRA1-related CSVD may be seen in patients of non-Asian ethnicity without alopecia. These case reports extend the clinical and radiographic spectrum of HTRA1-related CSVD.     

CADASIL presenting with a movement disorder: a clinical study of a Chilean kindred.

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a hereditary vascular disease that usually begins with migraine, followed by repeated strokes and progressive dementia. We describe an unusual clinical presentation of this condition in members of a Chilean family with an established NOTCH3 mutation. We report early clinical, neuropsychological, transcranial ultrasound, magnetic resonance imaging (MRI), cerebral blood flow, and skin biopsy findings on these patients. Of the patients, 2 presented with facial dystonia, 1 of whom had abnormal single photon emission computed tomography and transcranial ultrasound studies after normal brain MRI scans. Our report emphasizes that CADASIL must be considered in the study of patients with secondary dystonia.     

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.     

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.     

Sporadic vascular dementia as clinical presentation of a new missense mutation within exon 7 of NOTCH3 gene

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a genetic disease characterized by ischemic stroke with early onset, migraine, seizures, and vascular dementia. CADASIL is associated with mutations within NOCT3 gene, mainly clustered in exons 3 and 4. We report a case of CADASIL presenting progressive subcortical dementia in the sixth decade. Neither family history, nor acute ischemic events were present. MRI findings were typical for CADASIL. NOTCH3 analysis disclosed a new missense mutation within exon 7, leading to the substitution of cysteine 366 with a tryptophan (Cys366Trp). Our finding suggests CADASIL diagnosis must be considered in patients with vascular dementia also in absence of stroke-like events and of family history.     

Genetic determinants of juvenile stroke

Stroke is a heterogeneous multifactorial disorder. Although epidemiological data from twin and family studies provide substantial evidence for a genetic basis for stroke, the contribution of genetic factors identified so far is small. Large progress has been made in single-gene disorders associated with ischemic stroke, particularly at young age. The identification of NOTCH3 mutations in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL) and of TREX1 mutations in retinal vasculopathy with cerebral leukodystrophy (RVCL) have led to new insights on lacunar stroke and small-vessel disease. Studies of sickle-cell disease have drawn attention to the importance of modifier genes and of gene-gene interactions in determining stroke risk, while there is now evidence that Fabry disease is an underdiagnosed cause of stroke. Furthermore, stroke is a well-known complication of several heritable connective tissue disorders, including Marfan's syndrome (FBN1 mutations) and Ehlers-Danlos syndrome type IV (COL3A1 mutations), which predispose to cervical artery dissection, the most frequent cause of cerebral ischemia at young age. By contrast, little is known about the genes associated with multifactorial stroke. The reported genome-wide association studies of ischemic stroke have shown that no single common genetic variant imparts major risk. Pharmacogenomic studies have uncovered genetic determinants of response to warfarin, statins and clopidogrel. Larger studies with samples numbering in the thousands are ongoing to identify common variants with smaller effects on risk. This approach will contribute to the identification of additional genes, novel pathways, and eventually novel therapeutic approaches to cerebrovascular disorders.