NOTCH基因与CADASIL的分子发生机制

CADASIL是伴有皮质下梗死和白质脑病的常染色体显性遗传性脑动脉病，近年来，有关该病的研究主要着眼于其分子遗传学的研究，并已经取得巨大的进步，本文就其基因定位、点突变和NOTCH基因家族在该病发病中的地位和作用进行踪述。     

不完全外显的遗传性痉挛性截瘫一家系临床与致病基因排除定位分析

目的 描述一个遗传了4代的不完全外显的遗传性痉挛性截瘫(hereditary spastic paraplegia,SPG)大家系的临床特征,并进行致病基因排除定位分析.方法 对SPG家系内11例患者的临床资料进行回顾性分析,并采用荧光多重PCR、毛细管凝胶电泳、Linkage软件包,选择对已定位常染色体显性遗传致病基因位点附近微卫星标记进行连锁分析.结果 该SPG家系的11例患者的发病年龄2～10岁,表现为缓慢进展的双下肢僵硬无力,四肢肌张力轻度增高,双上肢为主的腱反射亢进,剪刀步态和病理征阳性,无小便失禁或尿频、感觉障碍、眼震、痴呆等;遗传学分析该家系符合常染色体显性遗传,但外显不完全,连锁分析和突变分析发现该家系与已知的常染色体显性遗传SPG致病基因位点不连锁.结论 该SPG家系具有典型的"单纯型"痉挛性截瘫临床特点,发病年龄早,上肢体征较下肢明显,遗传学分析不支持该家系与已定位常染色体显性遗传位点相连锁,是一种新的SPG亚型.     

遗传性非息肉病性结直肠癌的家系和染色体脆性部位研究

目的：报道一个遗传性非息肉病性结直肠癌的家系和细胞遗传学特征。方法：家系调查通过查阅患者病历,走访经治医生和知情成员所获得。细胞遗传学研究采用了外周血淋巴细胞脆性部位培养技术和G显带分析方法。结果：该家族患者符合阿姆斯特丹诊断标准,先证者祖父母后代发病呈常染色体显性遗传,致病基因来源于先证者祖母。细胞遗传学研究显示9例成员染色体异常率高达55．6％,其中1例正常成员亦检到脆性部位,是重点监测和随访的末病对象;表现为显性遗传的先证者祖父母后代5例成员与5例患者染色体异常率均达80％（4／5）。结论：根据系谱中发病规律和患者很高的染色体脆性部位检出率为该家族成员的发病预测、筛查、早诊断、早治疗具有简便、实用、经济的特点和应用价值,可让部分家族成员避免反复检查的痛苦。     

Ⅰ型神经纤维瘤一家系4例的分析报告

目的 分析一个面部有巨大神经纤维瘤家系的临床表现及遗传方式.方法 根据美国国立卫生研究院(NIH)提出的神经纤维瘤诊断标准进行诊断,通过染色体检查和家系分析方法确定遗传方式.结果 家系12名成员中有3名患者表现出Ⅰ型神经纤维瘤的4项临床特征,染色体检查无异常,家系分析表现出常染色体显性遗传特点.结论 该家系为Ⅰ型神经纤维瘤家系,遗传方式为常染色体显性遗传.     

NOTCH基因与CADASIL的分子发生机制

CADASIL 是伴有皮质下梗死和白质脑病的常染色体显性遗传性脑动脉病 ,近年来 ,有关该病的研究主要着眼于其分子遗传学的研究 ,并已经取得巨大的进步 ,本文就其基因定位、点突变和 NOTCH基因家族在该病发病中的地位和作用进行综述。     

CADASIL研究新进展

伴有皮层下梗死和白质脑病的常染色体显性遗传性脑动脉病(cerebral autosome dominant arteriopathy with subcortical Infarcts and leukoencephalopathy,CADASIL)是近年来证实遗传因素参与脑血管病发病的重要进展之一.其主要临床特点为家族遗传方式起病、中年发病、逐渐进展的缺血样卒中样病程、进行性血管性痴呆、先兆症状的偏头痛发作和精神症状.MRI、CT检查可见多发性梗死、脑白质变性.脑组织活检示小血管玻璃样变、噬锇颗粒.分子遗传学研究发现19号染色体Notch3基因突变与本病有关.     

遗传性牙龈纤维瘤一家系临床特征及SOS1基因突变筛查

目的检测分析遗传性牙龈纤维瘤病(HGF)一家系患者的临床特点及致病基因。方法通过诊断HGF先证者,收集一个中国汉族非综合征性HGF家系,患者牙龈组织作HE和MASSON染色进行组织病理学分析。采集家族中患者及健康个体的外周血,提取基因组DNA,PCR扩增SOS1基因各外显子并作直接测序,同源性比较分析。结果该中国汉族HGF家系中共有四代10人,其中患者4人(男2人,女2人),符合常染色体显性遗传模式。患者牙龈组织病理显示牙龈黏膜上皮钉突延长,纤维结缔组织增生,MASSON染色显示胶原纤维异常增生。基因突变检测未在SOS1基因外显子区域发现突变点。结论该家系临床特征典型,符合常染色体显性遗传模式。HGF具有一定的遗传异质性,SOS1基因可能不是该中国汉族人HGF家系的致病基因。     

SPG4基因的遗传学研究

遗传性痉挛性截瘫(hereditary spastic paraplegia,HSP),又称为家族性Strümpell-Lorrain病,是一种具有临床及遗传高度异质性的神经系统遗传病,患病率为2/10万～9.6/10万,表现为缓慢进展的双下肢无力及痉挛性截瘫.根据遗传方式不同HSP可分为常染色体显性遗传、常染色体隐性遗传和X-连锁隐性遗传,以常染色体显性遗传最常见.目前已经发现40个HSP基因位点,已克隆19个疾病基因.其中spastin基因突变所致的遗传性痉挛性截瘫4型(spastic paraplegia-4,SPG4)约占常染色体显性遗传的HSP的40%.基因检测是诊断该病的金标准,有助于早期诊断、症状前诊断及产前诊断.动物模型的研究对揭示HSP的分子病理机制有重要作用,本文就SPG4基因的遗传学研究作一概述.     

九个家族性慢性良性天疱疮家系的临床和遗传特点分析

目的了解家族性慢性良性天疱疮(Hailey-Hailey disese,HHD)的临床表型和遗传学特点。方法对收集的9个HHD家系中患者的临床表型和遗传特点进行总结和分析。结果(1)HHD在家系中的传递符合常染色体显性遗传模式;(2)发病年龄多在20岁～30岁,好发于腹股沟、腋下、颈等部位;(3)临床表型特征为皮肤皱褶部位反复出现水疱和糜烂;(4)同一家系中不同患者的表现度不同;(5)少数患者可伴发尖锐湿疣、白癜风等皮肤病。结论HHD是一种具有高度外显率的常染色体显性遗传性皮肤病,临床表型以皮肤皱褶部位反复出现水疱和糜烂为特征,但不同患者表现度可存在差异。     

Goldenhar 综合征家系的临床表型和遗传学分析

目的分析1组Goldenhar综合征家系的临床表现及遗传学特征。方法我们随访到1组4代33人的Goldenhar综合征家系，对目前存活的29人进行了临床表型和遗传学的初步分析。结果家系内有Goldenhaar综合征患者5人．临床表现具高度多样性，累及眼、耳、脊柱、颜面、口腔等多个器官和系统的发育不良，在遗传方式上属于常染色体显性遗传。从细胞遗传学水平对家系中成员进行染色体检查，未发现核型异常。结论该Goldenhar综合征家系属常染色体显性遗传，染色体检查未发现核型异常。     

A novel mutation (C67Y)in the NOTCH3 gene in a Korean CADASIL patient

We report a 52-yr-old Korean woman with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) whose diagnosis was confirmed by skin biopsy and the presence of a novel mutation in the NOTCH3 gene. The patient's clinical features were rather unusual in that 1) clinical presentations were only two episodes of stroke and mild dementia unaccompanied by mood disturbances or migraine, and 2) there was no family history. Brain MRI showed T2 hyperintensities in both temporal pole areas in line with the recent suggestion by O'Sullivan et al. that the abnormality could be a radiologic marker of CADASIL. FDG-PET also showed a hypometabolism in the temporal pole areas with an abnormal finding on MRI in addition to the hypometabolism in cortical and subcortical regions. We could learn from this case that CADASIL may be included in the differential diagnoses in patients with vascular dementia associated with a small vessel disease, even in the absence of a family history, especially when there are no known stroke risk factors and when the MRI shows T2 hyperintensity in the temporal pole regions.     

Vasculopathic Changes of CADASIL Can Be Focal in Skin Biopsies

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a newly described cause of vascular dementia. Pathologic examination shows multiple small infarcts in the deep cerebral white matter together with a nonatherosclerotic, nonamyloid angiopathy involving the media of small cerebral arteries. Ultrastructurally, characteristic granular material is present in the basal lamina of vascular smooth muscle cells in cerebral and extracerebral blood vessels. The ultrastructural changes have also been demonstrated in skin biopsies of affected patients; consequently, some investigators have recently recommended skin biopsies for the diagnosis of CADASIL. This study describes a 54-year-old male with a family history for strokes who had clinical and radiological features suggestive of CADASIL. A skin biopsy was performed to confirm the diagnosis. Initially, the characteristic vasculopathic changes of CADASIL were not identified within small blood vessel walls. However, multiple deeper sections in other areas showed electron-dense material associated with vascular smooth muscle cells, characteristic of CADASIL. Subsequent genetic testing demonstrated a single nucleotide substitution at position 659 on chromosome 19p13.1 causing an amino-acid change (Cys Phe), a finding indicative of CADASIL. The involvement of blood vessels within the dermis makes skin biopsy a useful adjunct in the diagnosis of CADASIL. However, as illustrated by this case, the findings may be focal, requiring a thorough evaluation of the entire biopsy specimen.     

Vasculopathic Changes of CADASIL Can Be Focal in Skin Biopsies

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a newly described cause of vascular dementia. Pathologic examination shows multiple small infarcts in the deep cerebral white matter together with a nonatherosclerotic, nonamyloid angiopathy involving the media of small cerebral arteries. Ultrastructurally, characteristic granular material is present in the basal lamina of vascular smooth muscle cells in cerebral and extracerebral blood vessels. The ultrastructural changes have also been demonstrated in skin biopsies of affected patients; consequently, some investigators have recently recommended skin biopsies for the diagnosis of CADASIL. This study describes a 54-year-old male with a family history for strokes who had clinical and radiological features suggestive of CADASIL. A skin biopsy was performed to confirm the diagnosis. Initially, the characteristic vasculopathic changes of CADASIL were not identified within small blood vessel walls. However, multiple deeper sections in other areas showed electron-dense material associated with vascular smooth muscle cells, characteristic of CADASIL. Subsequent genetic testing demonstrated a single nucleotide substitution at position 659 on chromosome 19p13.1 causing an amino-acid change (Cys Phe), a finding indicative of CADASIL. The involvement of blood vessels within the dermis makes skin biopsy a useful adjunct in the diagnosis of CADASIL. However, as illustrated by this case, the findings may be focal, requiring a thorough evaluation of the entire biopsy specimen.     

常染色体显性遗传病伴皮质下梗死和白质脑病的临床研究进展

常染色体显性遗传病伴皮质下梗死和白质脑病(cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy,CADASIL)是一种临床上罕见的以中年人发病的遗传性微小动脉疾病,由19号染色体上Notch3基因突变所致的遗传性卒中疾病.该病患者初期多有偏头痛发作史,中年时反复发作短暂性脑缺血发作(transient ischemic attack, TIA)或缺血脑卒中,病程晚期患者可出现进行性加重的痴呆及精神症状.头颅磁共振成像(magnetic resonance imaging,MRI)检查显示双侧大脑半球多发的白质病变,为本病特征性的影像学表现.本文总结了该病临床研究进展,包括临床表现、神经影像学表现、CADASIL量表、病理学及分子遗传学,以加深对该病的认识,从而有助于早期诊断,减少误诊和漏诊.     

Genetic analysis of adult leukoencephalopathy patients using a custom‐designed gene panel

Leukoencephalopathies encompass all clinical syndromes that predominantly affect brain white matter. Genetic diagnosis informs clinical management of these patients, but a large part of the genetic contribution to adult leukoencephalopathy remains unresolved. To examine this genetic contribution, we analyzed genomic DNA from 60 Japanese patients with adult leukoencephalopathy of unknown cause by next generation sequencing using a custom‐designed gene panel. We selected 55 leukoencephalopathy‐related genes for the gene panel. We identified pathogenic mutations in 8 of the 60 adult leukoencephalopathy patients (13.3%): NOTCH3 mutations were detected in 5 patients, and EIF2B2, CSF1R, and POLR3A mutations were found independently in 1 patient each. These results indicate that cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) caused by NOTCH3 mutations is the most frequent adult leukoencephalopathy in our cohort. Moreover, brain imaging analysis indicates that CADASIL patients who do not present typical phenotypes may be underdiagnosed if not examined genetically.     

Exome sequencing reveals an unexpected genetic cause of disease: NOTCH3 mutation in a Turkish family with Alzheimer's disease

Alzheimer's disease (AD) is a genetically complex disorder for which the definite diagnosis is only accomplished postmortem. Mutations in 3 genes (APP, PSEN1, and PSEN2) are known to cause AD, but a large number of familial cases do not harbor mutations in these genes and several unidentified genes that contain disease-causing mutations are thought to exist. We performed whole exome sequencing in a Turkish patient clinically diagnosed with Alzheimer's disease from a consanguineous family with a complex history of neurological and immunological disorders and identified a mutation in NOTCH3 (p.R1231C), previously described as causing cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). Complete screening of NOTCH3 in a cohort of 95 early onset AD cases and 95 controls did not reveal any additional pathogenic mutations. Although the complex history of disease in this family precluded us to establish segregation of the mutation found with disease, our results show that exome sequencing is a rapid, cost-effective and comprehensive tool to detect genetic mutations, allowing for the identification of unexpected genetic causes of clinical phenotypes. As etiological based therapeutics become more common, this method will be key in diagnosing and treating disease.     

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL)

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) is a recently described neurovascular disease affecting young to middle age individuals. The disease is caused by mutations in the Notch3 gene located in the short arm of chromosome 19. Clinically, the disease is characterized by migrainous headaches (with or without aura), mood disturbances, focal neurologic deficits, transient ischemic attacks, strokes, and dementia. Pathologically, the disease is characterized by a stereotypic degeneration of the arterial walls (especially in the intracranial compartments) with deposition in the media of a nonatheromatous, nonamyloidotic substance that under the electron microscope (EM) appears as a granular osmiophilic material (GOM), pathognomonic for the disease. The nature of the GOM is undetermined and the pathogenesis remains to be elucidated. A review of current literature in English language is presented on the clinical, radiologic, pathologic, and genetic features of CADASIL.     

Quantitative Vascular Pathology and Phenotyping Familial and Sporadic Cerebral Small Vessel Diseases

We quantified vascular changes in the frontal lobe and basal ganglia of four inherited small vessel diseases (SVDs) including cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), pontine autosomal dominant microangiopathy and leukoencephalopathy (PADMAL), hereditary multi‐infarct dementia of Swedish type (Swedish hMID), and hereditary endotheliopathy with retinopathy, nephropathy, and stroke (HERNS). Vascular pathology was most severe in CADASIL, and varied with marginally greater severity in the basal ganglia compared to the frontal lobe. The overall sclerotic index values in frontal lobe were in the order CADASIL ≥ HERNS > PADMAL > Swedish hMID > sporadic SVD, and in basal ganglia CADASIL > HERNS > Swedish hMID > PADMAL> sporadic SVD. The subcortical white matter was almost always more affected than any gray matter. We observed glucose transporter‐1 (GLUT‐1) protein immunoreactivities were most affected in the white matter indicating capillary degeneration whereas collagen IV (COL4) immunostaining was increased in PADMAL cases in all regions and tissue types. Overall, GLUT‐1 : COL4 ratios were higher in the basal ganglia indicating modifications in capillary density compared to the frontal lobe. Our study shows that the extent of microvascular degeneration varies in these genetic disorders exhibiting common end‐stage pathologies but is the most aggressive in CADASIL.     

Multi-organ investigation in 16 CADASIL families from central Italy sharing the same R1006C mutation

Cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) may involve many target organs with relevant variability among affected individuals. We performed a multi-organ assessment tapping nervous system, skeletal muscle and cardiovascular system in thirty-nine individuals belonging to 16 families from Central Italy sharing the same R1006C CADASIL mutation. Stroke prevalence was larger in female patients (66.7%) than in males (23.8%); high levels of CKemia were quite frequent (21.6%) and were related to a myopathy without mitochondrial alterations; several individuals had atrial septal aneurysm (10.3%). No specific relationships between common cardiovascular risk factors and clinical manifestations were found. The present systematic study thus identified several gender-related, myopathic and cardiovascular peculiarities of R1006C mutation. This kind of comprehensive approach is necessary to define clinical course, prognosis and treatment options for a multi-organ disease such as CADASIL.