一例女性Fabry病并发薄基底膜肾病及其家系调查

目的 了解具有两种遗传性疾病,即Fabry病并发薄基底膜肾病（TBMN）的临床病理和基因突变特点以及家系患病情况。 方法 总结分析本院收治的1例41岁女性Fabry病并发TBMN患者的临床病理特征和基因突变情况,同时对家系成员进行调查及相关检测。 结果 先证者呈现典型的Fabry病的肾外临床表现,包括皮疹、神经痛、眩晕、耳鸣、肥厚型心肌病等,同时亦有蛋白尿、镜下血尿及高血压等肾脏受累表现;肾活检光镜下病理改变为局灶性节段性肾小球硬化（FSGS）,部分足细胞空泡变性;电镜下肾小球脏层上皮细胞胞质内多数髓磷脂小体形成,肾小球基底膜（GBM）弥漫性变薄,厚度为（216±31） nm。家系调查及基因突变检测显示先证者女儿除有典型Fabry病肾外表现外,亦有以血尿为主的肾脏症状。先证者的1个妹妹仅表现为镜下血尿。先证者及其女儿α-半乳糖苷酶 A（α-Gal A）活性分别为33和75活性单位（正常参考值为100~500活性单位）,且2人均携带新发现的GLA基因突变——1208ins21 bp及COL4A3基因多态性——c:3627 G>A（p:M1209I）。仅表现为镜下血尿的先证者的妹妹仅携带COL4A3基因的c:3627 G>A（p:M1209I）多态性,α-Gal A活性正常,无GLA基因突变。 结论 对于Fabry肾病患者呈现血尿,尤其是表现为家族性血尿时,应考虑并认真排除并发TBMN的可能。     

11个Fabry病家系的α-半乳糖苷酶A活性及GLA基因检测

目的 建立Fabry病α-半乳糖苷酶A（α-gal A）酶活性及基因检测体系,并对基因型临床表型进行分析。方法 检测11个Fabry病家系先证者及家系成员外周血粒细胞α-gal A活性及GLA基因。酶活性检测采用底物荧光法,基因检测采用PCR直接测序法,并进行临床评估。结果 在11个Fabry病家系中检出9种GAL基因突变,包括5个错义突变（R301Q、I91T、G132R、F273L、D165Y）,2个无义突变（W236X、R342X）,1个单碱基缺失（1082delG）和1个大片段缺失（44 bp nt．1077）,其中4种为新突变（D165Y、F273L、1082delG、44 bp nt．1077）。11个家系中通过基因及酶活性检测,确诊男性半合子13例,女性杂合子12例。男性半合子α-gal A酶活性显著下降,女性杂合子α-gal A酶活性部分下降,1/4女性杂合子的α-gal A酶活性处于正常范围内。结论 确诊了11个Fabry病家系的GLA基因突变类型,并筛出所有家系中先证者以外的患者14例。外周血粒细胞α-gal A酶活性和GAL基因检测是筛查和诊断Fabry病的有效手段。     

Fabry病家系的α-半乳糖苷酶A基因突变研究

目的 通过检测3个Fabry病家系基因突变类型明确基因诊断,并进行家系成员的基因型检测.方法 通过PCR和直接测序的方法,对3个Fabry家系的先证者及部分家系成员外周血DNA进行α-半乳糖苷酶A编码GLA基因7个外显子及其相邻内含子的DNA序列检测.结果 （1）先证者1的GLA基因7号外显子内1142位点发生碱基缺失（1142delG）,1142位碱基G的缺失导致蛋白质翻译在390位氨基酸提前终止,该突变国内外均未见报道;（2）先证者2的GLA基因6号外显子内902位点存在1个错义突变,碱基G被A取代,导致其编码的第301位氨基酸由精氨酸变为谷氨酰胺（902G＞A,R301Q）;（3）先证者3的GLA基因3号外显子内484位点存在1个错义突变,碱基T被C取代,导致其编码的第142位氨基酸由半胱氨酸变为精氨酸（484T＞C,C142R）.在3个家系的部分成员中进行基因检测,检出GLA突变基因携带者共6例,其中男性半合子1例,女性杂合子5例,突变类型均与相应先证者符合.100条正常X染色体对照中均未发现上述位点异常.结论 本研究在3个Fabry病家系中检出3种GLA基因突变,其中1142delG为新发现的突变,并在3个家系的部分家系成员中检出男性半合子1例,女性杂合子5例.     

一个Fabry病家系的基因突变和临床表型研究

目的对一个临床表现以肾脏损害为主的Fabry病家系进行调查,分析其基因突变和临床特点。探讨不同突变类型对临床表型的影响。方法收集该例先证者及其家族成员的临床资料。采集先证者及其姐姐和一名健康对照者的外周血,应用荧光底物法检测a半乳糖苷酶A（toga[A）的酶活性;提取血液基因组DNA,PCR分段扩增α—galA基因的7个外显子,产物纯化后进行DNA测序,检测是否存在突变位点。结果①临床调查患者家系发现5名男性患者,均发展至终末期肾脏疾病（endstage renaldisease,ESRD）,伴有肢端疼痛、皮肤血管胶质瘤及少汗等Fabry病典型表现;3名女性杂合子,临床表现各异;②regalA活性检测示先证者酶活性明显下降,其姐姐α-galA活性在正常范围;③基因检测发现先证者regalA基因第2外显子的第112个密码子上的碱基胞嘧啶（c）被胸腺嘧啶（T）替代,因此导致由原本翻译的精氨酸变成了半胱氨酸（p．R112C）,形成错义突变,从而导致α-galA酶活性的降低或缺乏。结论发现了一个新的Fabry病家系,并明确了该家系的基因突变特点。在此家族中,我们发现除了外胚层组织损害,α—galA基因错义突变p．R112C亦可导致中胚层组织（如肾脏）的严重损害。     

X连锁遗传性脑积水的L1CAM基因突变检测及产前诊断

目的探讨X连锁遗传性脑积水的L1CAM基因突变检测和产前诊断的可行性。方法应用PCR-直接序列测定法对一个X连锁遗传性脑积水家系进行L1CAM基因突变分析,并对孕妇进行了产前诊断。结果该家系先证者在L1CAM基因外显子28存在c.3581CT(p.S1194L)致病突变,患者的姐姐和母亲均为携带者,姨和表妹均未检测到该致病突变。对携带有该基因突变的姐姐先后进行了3次产前基因诊断(包括1例羊水检测,1例双胎羊水检测,1例绒毛检测),均证实为获得致病突变的男性胎儿。结论对于B超发现的男性脑积水胎儿,可以对其进行L1CAM基因突变筛查,有助于对下次妊娠的复发风险或携带者的妊娠风险进行评估;对携带突变基因的孕妇进行产前诊断,避免患儿的出生。     

法布里病精准治疗的研究进展

法布里病是一种X连锁遗传的溶酶体贮积症, 病因为编码α-半乳糖苷酶A(α-galactosidase, α-Gal A)的GLA基因突变, 导致α-Gal A酶活性下降或缺乏, 底物及其代谢物在细胞及组织中蓄积, 最终导致多脏器衰竭。近年来, 特异性治疗药物及基因技术的兴起, 推动了法布里病精准医疗的进展。酶替代治疗作为法布里病特异性治疗的里程碑事件, 可延缓疾病进展, 改善患者生活质量。但并非所有GAL基因突变携带者都需要积极干预, 需要甄别其中有适应证的患者, 并予以个体化治疗。酶增强治疗适用于有"适应性突变"的患者, 且存在一定的临床应用局限。一些新治疗方法, 如底物减少疗法、第2代酶替代治疗和基因治疗已在临床试验中, 有望为法布里病患者带来福音。该文综述了法布里病精准治疗的研究进展, 为法布里病患者的药物选择及其不良反应的防控提供依据, 期望未来的治疗策略进一步向精准型方向发展。     

汉族人群青少年特发性脊柱侧凸家系中存在复合型杂合DOCK9基因突变

目的探讨青少年特发性脊柱侧凸(AIS)家系中可能的致病基因突变。方法对一个汉族AIS家系的3名成员(先证者及其表型正常的父母)进行全基因组测序,筛选潜在的致病基因突变,并通过Sanger测序验证所有发现的突变。结果在AIS家系中发现DOCK9基因存在复合型杂合基因突变c.3259TC(p.F1087L)和c.2465AG(p.Y822C)。患者的父母是未出现AIS表型的突变基因携带者,父亲携带c2465AG突变,而母亲携带c.3259TC突变。结论复合型杂合DOCK9基因突变可能导致AIS的发生,其在AIS发生机制中的作用有待于进一步探索。     

Fabry病的肾脏表现及治疗进展

Fabry病属于溶酶体蓄积病，是一种罕见的X连锁遗传性疾病，系由于先天性溶酶体α-半乳糖苷酶A活性缺陷导致鞘糖脂代谢异常，进而在体内多系统包括肾脏、皮肤、角膜及心脏等部位的异常堆积致病。Fabry病属单基因遗传病，致病基因GLA基因位于Xq22，编码α-半乳糖苷酶A。以往调查显示在男性新生儿中发病率约为1／40000。     

E-钙黏素基因与遗传性胃癌的关系

例先证者肿瘤标本表现为启动子甲基化,5例先证者肿瘤标本中发现了6个突变,包括两个同义突变和4个错义突变,在正常组织未发现同样的种系突变;4例先证者表现为既有体细胞突变又有启动子甲基化;1例既没有体细胞突变也没有启动子甲基化;2例患者仅表现为启动子甲基化,1例仅发现体细胞突变.结论 CDH1种系突变在我国遗传性胃癌中可能并不常见,CDH1基因的体细胞突变和启动子甲基化可能协同的导致遗传性胃癌患者CDH1基因下调.     

中国人恶性高热家系蓝尼定受体-1基因的筛查

目的 筛查中国人恶性高热(MH)家系的蓝尼定受体-1(RYR1)基因.方法 提取确诊为MH的先证者及家系其他成员外周血白细胞的基因组DNA,采用PCR扩增先证者RYR1基因的部分外显子,并进行直接测序,采用Fok Ⅰ限制酶分析验证先证者及家系其他成员基因突变情况.结果 先证者RYR1基因第6 724位碱基C突变为T(c.6724 C＞T),所编码第2 206位氨基酸由苏氨酸变为甲硫氨酸(p.T 2206 M),此突变在白种人已报道;先证者的4个子女中有2个为该错义突变携带者,为MH易感者.结论 中国人MH易感者携带与白种人MH易感者相同的RYR1基因突变.     

A Novel Small Insertion Mutation,C.1030_1031ins (T) in α-Galactosidase A Leads to Renal Variant Fabry Disease

Fabry disease is a rare X-linked recessive glycosphingolipid storage disease that is caused by a deficiency of the lysosomal α-galactosidase A (GLA) enzyme, encoded by the GLA gene. This deficiency leads to the accumulation of glycosphingolipids throughout the body, which, in turn, causes multisystem diseases associated with renal, cardiovascular, and cerebrovascular complications. Recent molecular studies of GLA have demonstrated the existence of atypical variants in Fabry disease, suggesting significant genotype–phenotype correlations. In this study, we describe a renal variant of Fabry disease caused by a novel small insertion mutation in the GLA gene.     

Anderson–Fabry disease: a case-finding study among male kidney transplant recipients in Austria

The diagnosis of Anderson–Fabry disease is often delayed or even missed. As severe renal manifestations are a hallmark of alfa-galactosidase A (AGAL) deficiency, we tested the hypothesis that Anderson–Fabry disease is under-recognized among male kidney transplant recipients. This nation-wide study in Austria enrolled 1306 patients (ca 65% of all kidney transplanted males) from 30 kidney centers. AGAL activity was determined from filter paper dried blood spots by a fluorescence assay. A positive screening test was defined by an AGAL activity below 1.5 nmol/h/ml. In patients with a positive blood spot-screening test, AGAL activity was re-examined in peripheral blood leukocytes. Genetic testing for mutations in the GLA gene was performed by sequencing to confirm the diagnosis of Anderson–Fabry disease. Two previously not recognized cases with Anderson–Fabry disease were identified. Our study is the first showing that a diagnosis of Anderson–Fabry disease can be missed even in patients who undergo kidney transplantation. Case-finding strategies may be considered a useful tool for diagnosis of this rare disease that may be somewhat more prevalent among kidney transplant recipients compared with dialysis populations.     

Henoch-Schoenlein nephritis in adults-clinical features and outcomes in Finnish patients

Fabry disease, an X-linked lysosomal storage disease, results from the deficient activity of the enzyme alpha-galactosidase A (alpha-Gal A) and the progressive accumulation of globotriaosylceramide (GL-3) and related glycosphingolipids. In classically affected males with this inherited nephropathy, early and marked GL-3 deposition in the podocytes leads to proteinuria in childhood or adolescence. With increasing age, GL-3 deposition in renal microvascular endothelial cells, and to a lesser extent in interstitial and mesangial cells, leads to renal insufficiency in the third to fifth decades of life. Recently identified "renal variants" who lack the classical disease manifestations of acroparesthesias, angiokeratoma, hypohidrosis, and characteristic corneal/lenticular opacities also develop renal failure. In contrast, "cardiac variants" who also lack the classical phenotype, develop proteinuria in adulthood, but survive a normal lifespan without developing renal failure. Here, we review the renal involvement and pathology in the classical, renal and cardiac variant phenotypes, and present highlights of the preclinical studies and clinical trials that demonstrated the safety and effectiveness of recombinant alpha-Gal A replacement for this inherited nephropathy.     

A novel small insertion mutation, C.1030_1031ins (T) in α-galactosidase A leads to renal variant fabry disease

Fabry disease is a rare X-linked recessive glycosphingolipid storage disease that is caused by a deficiency of the lysosomal α-galactosidase A (GLA) enzyme, encoded by the GLA gene. This deficiency leads to the accumulation of glycosphingolipids throughout the body, which, in turn, causes multisystem diseases associated with renal, cardiovascular, and cerebrovascular complications. Recent molecular studies of GLA have demonstrated the existence of atypical variants in Fabry disease, suggesting significant genotype-phenotype correlations. In this study, we describe a renal variant of Fabry disease caused by a novel small insertion mutation in the GLA gene.     

Progressive podocyte injury and globotriaosylceramide (GL-3) accumulation in young patients with Fabry disease

Progressive renal failure often complicates Fabry disease, the pathogenesis of which is not well understood. To further explore this we applied unbiased stereological quantitative methods to electron microscopic changes of Fabry nephropathy and the relationship between parameters of glomerular structure and renal function in 14 young Fabry patients (median age 12 years). Renal biopsies were obtained shortly before enzyme replacement therapy from these patients and from nine normal living kidney donors as controls. Podocyte globotriaosylceramide (GL-3) inclusion volume density increased progressively with age; however, there were no significant relationships between age and endothelial or mesangial inclusion volume densities. Foot process width, greater in male Fabry patients, also progressively increased with age compared with the controls, and correlated directly with proteinuria. In comparison to the biopsies of the controls, endothelial fenestration was reduced in Fabry patients. Thus, our study found relationships between quantitative parameters of glomerular structure in Fabry nephropathy and age, as well as urinary protein excretion. Hence, podocyte injury may play a pivotal role in the development and progression of Fabry nephropathy.     

Fabry Disease in Hemodialysis Patients in Southern Brazil: Prevalence Study and Clinical Report

Background. Fabry disease (FD) is a lysosomal storage disorder caused by a deficiency of α-Galactosidase A (α-Gal A). Fabry nephropathy typically progresses throughout the fifth decade to end-stage renal disease (ESRD), requiring hemodialysis and/or kidney transplantation. Objective. To estimate the prevalence of FD among ESRD males on hemodialysis treatment in Rio Grande do Sul, the southernmost state of Brazil. Methods. Screening for α-Gal A activity was performed by a dried blood spot (normal reference value: >1.5 nmoles/hour/mL). Positive screening results were confirmed by plasma α-Gal A activity assay (reference value: >3.3 nmoles/hour/mL). Results. Five hundred fifty-eight male patients on hemodialysis were evaluated. Of these, only two had low α-Gal A activity and were diagnosed with Fabry disease (0.36%). One of these, age 42, had left ventricular hypertrophy and renal manifestations of Fabry disease without the classic symptoms. The other, age 46, had the classical manifestations of angiokeratomas, acroparesthesias, hypohidrosis, and ocular opacities. Conclusions. Although the prevalence of Fabry disease was very low in our study (0.36%), routine screening of male hemodialysis patients would enable earlier identification of many other affected relatives in their families who might benefit from specific clinical treatment.     

Significance of screening for Fabry disease among male dialysis patients

Background Fabry disease is an X-linked disorder resulting from a deficiency of the lysosomal enzyme alpha-galactosidase A(α-Gal A). Renal insufficiency is a very important manifestation and affects the prognosis of patients. Recently, a renal variant type that is characterized by low plasma α-Gal A activity and a milder phenotype, but which progresses to end-stage renal failure, has been reported. In this study, we clarified the incidence of this atypical variant of Fabry disease in hemodialysis patients. Methods We measured plasma α-Gal A activity in 450 male dialysis patients who had never been diagnosed with Fabry disease. Results The mean of the α-Gal A activity of the patients was 9.75 ± 3.20 nmol/h/ml, while the controls with classical Fabry (n = 3) were 0.52–1.04 nmol/h/ml. Among the patients, one patient was found to exhibit low α-Gal A activity in plasma (3.18 nmol/h/ml) and in leukocytes (0.639 nmol/h/mg). This patient was a 43-year-old Japanese man who had been on regular dialysis since the age of 23. He did not present typical clinical signs of classical Fabry, such as acroparesthesias or hypohidrosis, but did present renal insufficiency and severe left ventricular hypertrophy which had developed only recently, suggesting a variant form of Fabry disease. Sequencing of the DNA of this patient revealed a deletion of a single amino acid of valine in 10252. Conclusions A case of an atypical variant of Fabry among 450 male dialysis patients (0.22%) was found in the survey. This indicates the potential for undiagnosed Fabry disease among dialysis patients. The results of this study indicate the significance of screening for Fabry disease among male dialysis patients.