黏多糖病Ⅱ型的产前诊断

目的 应用胎儿羊水细胞艾杜糖-2-硫酸酯酶(iduronate-2-sulfatase,IDS)活性测定和基因突变检测的方法,对2例黏多糖病Ⅱ型(mucopolysaccharidosis typeⅡ,MPSⅡ)高危妊娠孕妇进行产前诊断.方法 胎儿羊水细胞培养,测定其IDS活性,并抽取羊水细胞基因组DNA,做胎儿性别鉴定和IDS基因突变检测.结果 2例胎儿羊水细胞IDS活性均明显下降,基因测序发现1例男性胎儿为IDS突变半合子,另1例女性胎儿为IDS基因突变携带者.结论 胎儿羊水细胞酶活性测定结合基因突变分析是一种准确、可靠、灵敏的MPSⅡ产前诊断方法,可对高危妊娠孕妇作出快速的产前诊断.     

肾上腺脑白质营养不良外显子6、7、8基因突变研究

目的 探讨中国人X-连锁隐性遗传肾上腺脑白质营养不良(adrenoleulkodystrophy)的分子发病机理。方法 应用聚合醇链反应(polymerase chain reaction)结合DNA测序技术(DNA sequencing)，对收集的6例患者、患者母亲及20名正常对照的ALD基因外显子6、7、8及其侧翼进行突变检测。结果 检出一例患者在ALD基因外显子6发生了Val517Ile(G→A)的碱基错义突变；另一侧患者在ALD基因外显子7发生了Gln556Arg(A→G)的碱基错义突变。ALD基因突变合成异常不稳定的蛋白(ALDP)，从而使VLCFA在脑白质、肾上腺及血浆聚集增多，导致疾病发生。结论 ALD基因突变是中国人X-连锁隐性遗传ALD发病原因之一。     

荧光原位杂交技术在羊水细胞染色体非整倍体产前诊断中的应用

目的探讨荧光原位杂交(FISH)技术在羊水胎儿染色体非整倍体产前诊断中的应用。方法对188例孕18-23周有产前诊断指征的孕妇选用13、18、21、X、Y特异性探针进行羊水间期细胞分析,并与羊水细胞中期细胞培养结果进行对照。结果在188例羊水FISH检测中均检测成功,其中正常核型175例,数目异常核型3例,与中期羊水染色体细胞培养结果一致,另有5例正常变异,5例结构异常FISH技术未能检出。结论荧光原位杂交(FISH)技术检测羊水胎儿染色体数目异常过程简单、快速、灵敏度较高、特异性较强,对于非整倍体产前诊断具有重要意义。     

用荧光原位杂交和核型分析技术对200例羊水标本的产前诊断

目的探讨荧光原位杂交(fluorescence in situ hybridization,FISH)技术和羊水细胞培养、核型分析技术在产前诊断胎儿染色体数目和结构异常中的价值。方法对200例孕18-23w、有产前诊断指征者,在B超引导下经腹抽取羊水后,一部分羊水应用13、18、21及X、Y染色体探针,对未培养的羊水间期细胞进行荧光原位杂交检测(FISH)。另一部分羊水进行细胞培养,进行染色体核型分析。结果 200例产前诊断者中,经FISH检测,羊水间期细胞染色体数目正常者189例,染色体数目异常者11例(其中7例47,XN,+21,1例47,XX,+18,2例45,X,1例47,XXY),此11例经引产后取脐血,经核型分析证实。进行细胞培养的标本中有2例培养失败,再次抽取羊水后培养成功。异常12例,其中数目异常11例,结构异常1例(新发罗氏易位),多态性9例。结论 FISH可以快速、准确的诊断胎儿染色体数目异常,核型分析可以全面的诊断胎儿染色体数目和结构异常,产前诊断中应将两者结合运用。     

应用SELDI-TOF-MS筛选神经系统先天畸形胎儿羊水诊断标志物

目的分析神经系统先天畸形胎儿羊水和神经系统正常胎儿羊水的蛋白质表达差异。方法选择8例神经系统畸形胎儿羊水,其中男性4例,女性4例;孕妇年龄21～32岁,平均年龄24.9岁;孕周19～34周,平均孕周23.1周。30例经超声检查神经系统正常胎儿羊水作为对照组,其中男性15例,女性15例;孕妇年龄22～29岁,平均年龄25.1岁;孕周19～22周,平均孕周21.2周。运用表面增强激光解吸离子化飞行时间质谱(SELDI-TOF-MS)蛋白质芯片技术检测神经系统先天畸形胎儿羊水和神经系统正常胎儿羊水蛋白质表达图谱。胎儿羊水用WCX2(弱阳离子交换)芯片检测,采用PBSⅡC型蛋白质芯片阅读机读取数据,Protein-Chip software 3.1软件采集数据,Biomarker Wizard软件分析两组羊水的蛋白质差异。结果 SELDI-TOF-MS技术检测发现神经系统先天畸形胎儿羊水和神经系统正常胎儿羊水的蛋白质存在差异表达,共有9个蛋白质水平发生变化,其中质/荷比4 967.526、5 258.056、11 717.010的差异蛋白质在神经系统异常组表达下调,2 540.415、3 107.119、3 396.759、4 590.965、5 589.200、6 429.417的差异蛋白质在神经系统异常组表达上调。结论神经系统先天畸形胎儿羊水和神经系统正常胎儿羊水之间的蛋白质谱有差异蛋白质表达,检测到9个代表性的差异蛋白质很可能是神经系统疾病胎儿的羊水特异性生物标志物。     

53例胎儿Yq11.21-11.223区域缺失或重复的遗传学分析

目的对153例Yq11.21-11.223区域缺失或重复的胎儿进行产前诊断,探讨Prental Bo Bs技术在产前诊断中的价值。方法对1973例有产前诊断指征的孕妇羊水细胞进行Prental Bo Bs和核型分析染色体,使用基因芯片对其结果进行验证。结果 1973例羊水中发现Yq11.21-11.223区域缺失或重复153例,异常率7.8%。其中26例胎儿筛查了父亲的染色体,父亲和胎儿染色体结果不一致的有3例。随访结果胎儿153例有6例引产,3例出生后不久夭折,其余均为正常男性胎儿,父亲有7例有轻微的少弱精症,其余均无临床症状。结论 Prental Bo Bs技术可以快速检测Yq11.21-11.223区域缺失或重复。     

济宁地区1608例孕中期羊水细胞染色体核型分析

目的通过对具有产前诊断指征的孕中期孕妇羊水细胞遗传学分析,确诊异常染色体胎儿,减少出生缺陷。方法对孕18～23W孕妇进行羊膜腔穿刺、羊水细胞培养并进行染色体核型分析。结果在1608例羊水细胞核型分析中,共检测出异常核型105例,异常核型检出率(不包括多态性)4.91%,终止妊娠48例。结论孕中期对有产前诊断指征的孕妇进行羊水细胞核型分析,可有效减少异常胎儿的出生,提高人口素质。     

PCR-SSP法检测羊水细胞A1、2、BO1、2血型基因型

目的通过PCR-SSP法检测羊水细胞A1、2、BO1、2血型基因型,产前诊断胎儿ABO血型.方法用PCR-SSP检测56例孕16w以上孕妇羊水细胞ABO血型基因型、用常规方法检测双亲及其胎儿或新生儿脐血ABO血型.结果 (1)56例羊水细胞用PCR-SSP法均检测出ABO血型基因型及其分型;(2)用常规血型检测方法检测脐血红细胞ABO血型抗原检出率为87.5%;(3)PCR-SSP法检测出羊水细胞ABO血型与父母血型按孟德尔遗传规则测出的胎儿血型符合率为100%.结论 (1)PCR-SSP法检测羊水细胞ABO血型基因型是准确产前诊断胎儿血型的方法.(2)PCR-SSP法检测羊水细胞ABO血型基因型可以精确至其亚型.     

广西贵港地区2148例中期妊娠羊水细胞染色体核型分析

目的染色体病是出生缺陷的重要原因之一,通过对具有产前诊断指征得中期妊娠孕妇自愿进行羊水细胞遗传学分析,检查异常染色体胎儿,减少出生缺陷。方法 2148例具有产前诊断指征的孕妇,在B超定位下进行羊膜腔穿刺术,抽取羊水细胞进行培养及染色体核型分析。结果在2148例羊水细胞染色体核型分析中,发现异常核型85例,终止妊娠21例。结论孕中期对有产前诊断指的孕妇进行羊水细胞核型分析,可有效地控制和减少异常胎儿的出生,提高人口出生素质。     

产前诊断中有关染色体嵌合体的诊断、处理及临床分析

目的探讨产前诊断中羊水检查发现胎儿染色体嵌合体的处理及临床分析。方法自2007年1月至2014年12月在北京大学人民医院产前诊断中心,对具有产前诊断指征的孕妇行羊膜腔穿刺,常规进行细胞培养及染色体核型分析。对羊水检测发现胎儿染色体符合"真性嵌合"标准的患者,建议行脐血穿刺复查或间期羊水FISH复查,同时结合超声检查结果综合分析和遗传咨询,继续妊娠者新生儿出生后随访。结果羊水穿刺10 571例患者中,共发现染色体嵌合体169例,其中真性嵌合体31例(0.29%),假性嵌合体138例(1.31%)。31例羊水检查疑似胎儿染色体嵌合的孕妇中,16例同意进一步脐血穿刺复查胎儿染色体,6例性染色体嵌合采用FISH技术对间期羊水进行检测,8人拒绝复查,1例胎死宫内。16例脐血复查患者中,4例复查结果未见异常(继续妊娠),12例与羊水中核型一致,仍为嵌合体(其中9例结合超声检测选择终止妊娠,2例继续妊娠,1例失访)。另6例行间期羊水FISH检测结果与中期羊水核型一致,依然为性染色体嵌合体(其中3例选择终止妊娠,2例继续妊娠,1例失访)。8例拒绝复查患者中2例选择继续妊娠,6例结合超声检查选择终止妊娠。另1例在孕期胎死宫内后引产。31例真性嵌合体患者中继续妊娠的10例孕妇均于新生儿出生后进行随访,目前没有发现智力及发育等方面明显异常。138例临床诊断为假嵌合体的患者均选择继续妊娠,对其进行出生后随访,17例失访,另121例中1例为室间隔缺损,2例出生低体重,其余目前未见异常。结论羊水培养及染色体分析中出现假性嵌合体几率较高,产前诊断中发现胎儿染色体嵌合者,应建议进一步复查,并结合超声结果进行相应遗传咨询,以防误诊。     

Evaluation of pharmacological induction of fatty acid beta-oxidation in X-linked adrenoleukodystrophy

X-linked adrenoleukodystrophy (X-ALD) is an inherited neurometabolic disorder associated with elevated levels of saturated unbranched very-long-chain fatty acids (VLCFA; C > 22:0) in plasma and tissues, and reduced VLCFA beta-oxidation in fibroblasts, white blood cells, and amniocytes from X-ALD patients. The X-ALD gene (ABCD1) at Xq28 encodes the adrenoleukodystrophy protein (ALDP) that is related to the peroxisomal ATP-binding cassette (ABCD) transmembrane half-transporter proteins. The function of ALDP is unknown and its role in VLCFA accumulation unresolved. Previously, our laboratory has shown that sodium 4-phenylbutyrate (4PBA) treatment of X-ALD fibroblasts results in increased peroxisomal VLCFA beta-oxidation activity and increased expression of the X-ALD-related protein, ALDRP, encoded by the ABCD2 gene. In this study, the effect of various pharmacological agents on VLCFA beta-oxidation in ALD mouse fibroblasts is tested. 4PBA, styrylacetate and benzyloxyacetate (structurally related to 4PBA), and trichostatin A (functionally related to 4PBA) increase both VLCFA (peroxisomal) and long-chain fatty acid [LCFA (peroxisomal and mitochondrial)] beta-oxidation. Isobutyrate, zaprinast, hydroxyurea, and 5-azacytidine had no effect on VLCFA or LCFA beta-oxidation. Lovastatin had no effect on fatty acid beta-oxidation under normal tissue culture conditions but did result in an increase in both VLCFA and LCFA beta-oxidation when ALD mouse fibroblasts were cultured in the absence of cholesterol. The effect of trichostatin A on peroxisomal VLCFA beta-oxidation is shown to be independent of an increase in ALDRP expression, suggesting that correction of the biochemical abnormality in X-ALD is not dependent on pharmacological induction of a redundant gene (ABCD2). These studies contribute to a better understanding of the role of ALDP in VLCFA accumulation and may lead to the development of more effective pharmacological therapies.     

肾上腺脑白质营养不良的产前分子诊断

目的对2名来自不同家系的肾上腺脑白质营养不良携带者所怀胎儿进行产前分子诊断。方法在采用STR位点分析方法排除母体基因组DNA污染后，应用扩增阻滞突变系统和DNA斑点杂交的方法对胎儿1羊水基因组DNA进行检测，应用PCR-RFLP和DNA序列测定对胎儿2羊水基因组DNA进行分析。结果在针对R617G突变的扩增阻滞突变系统中，当使用突变引物时，从胎儿1羊水DNA、胎儿1母亲基因组DNA均扩增出185bp的预期特异性条带，而胎儿1父亲和对照则未扩出。在斑点杂交反应中，应用R617G突变型探针时，只有胎儿1羊水细胞及其母亲外周血基因组DNA出现特异性显色斑点。在第2个家系中，先用PCR扩增出横跨P534R突变位点的基因组DNA片段（506bp），应用HoeⅡ酶切此产物，胎儿2以及其父亲、无关对照均未见切割，其母亲的部分产物被切割成396bp和110bp两个片段。对此PCR产物进行DNA序列测定，未在胎儿2中检测出P534R突变。结论胎儿1带R617G突变，为肾上腺脑白质营养不良半合子；胎儿2不带P534R突变，为正常半合子。     

Co-expression of mutated and normal adrenoleukodystrophy protein reduces protein function: implications for gene therapy of X-linked adrenoleukodystrophy

Inherited defects in the X-chromosomal adrenoleukodystrophy (ALD; ABCD1) gene are the genetic cause of the severe neurodegenerative disorder X-linked adrenoleukodystrophy (X-ALD). Biochemically the accumulation of very long-chain fatty acids, caused by impaired peroxisomal beta-oxidation, is the pathognomonic characteristic of the disease. Due to the X-chromosomal inheritance of X-ALD no data are available to clarify the question whether mutated adrenoleukodystrophy proteins (ALDPs) can negatively influence normal ALDP function. Here we show that restoration of beta-oxidation in X-ALD fibroblasts following transient transfection with normal ALD cDNA is more effective in ALDP-deficient fibroblasts compared with fibroblasts expressing normal amounts of mutated ALDP. Furthermore, we utilized the HeLa Tet-on system to construct a stable HeLa cell line expressing a constant level of endogenous ALDP and doxycycline-inducible levels of mutated ALDP. The induction was doxycycline dosage-dependent and the ALDP correctly localized. Interestingly, although mutated ALDP increased >6-fold in a dosage-dependent manner the total amount of ALDP (mutated and normal) remained approximately even as demonstrated by western blot and flow cytometric analyses. Thus, apparently mutated and normal ALDP compete for integration into a limited number of sites in the peroxisomal membrane. Consequently, increased amounts of mutated ALDP resulted in decreased peroxisomal beta-oxidation and accumulation of very long-chain fatty acids. These findings have direct implications on future gene therapy approaches for treatment of X-ALD, since in some patients a non-functional endogenous protein could act in a dominant negative way or displace the introduced, normal protein.     

ABCD1 mutations and the X‐linked adrenoleukodystrophy mutation database: Role in diagnosis and clinical correlations

X‐linked adrenoleukodystrophy (X‐ALD) is caused by mutations in the ABCD1 gene, which encodes a peroxisomal ABC half‐transporter (ALDP) involved in the import of very long‐chain fatty acids (VLCFA) into the peroxisome. The disease is characterized by a striking and unpredictable variation in phenotypic expression. Phenotypes include the rapidly progressive childhood cerebral form (CCALD), the milder adult form, adrenomyeloneuropathy (AMN), and variants without neurologic involvement. There is no apparent correlation between genotype and phenotype. In males, unambiguous diagnosis can be achieved by demonstration of elevated levels of VLCFA in plasma. In 15 to 20% of obligate heterozygotes, however, test results are false–negative. Therefore, mutation analysis is the only reliable method for the identification of heterozygotes. Since most X‐ALD kindreds have a unique mutation, a great number of mutations have been identified in the ABCD1 gene in the last seven years. In order to catalog and facilitate the analysis of these mutations, we have established a mutation database for X‐ALD ( http://www.x‐ald.nl ). In this review we report a detailed analysis of all 406 X‐ALD mutations currently included in the database. Also, we present 47 novel mutations. In addition, we review the various X‐ALD phenotypes, the different diagnostic tools, and the need for extended family screening for the identification of new patients. Hum Mutat 18:499–515, 2001. © 2001 Wiley‐Liss, Inc.     

肾上腺脑白质营养不良患者ABCD1基因第6外显子突变的初步分析

目的 检测肾上腺脑白质营养不良(adrenoleukodystrophy，ALD)(MIM300100)患者编码ALD蛋白的ABCD1基因[ATP-结合盒(ATP-binding cassette，ABC)超家族中D亚家族1]突变。方法 提取无亲缘关系的14例中国ALD患者及其中2例患者父母基因组DNA。聚合酶链反应(polymerase chainreaction，PCR)扩增ABCD1基因的第6外显子，以琼脂糖凝胶电泳鉴定PCR产物，PCR产物纯化后DNA直接测序。结果 证实3个患者的ABCD1基因第6外显子有突变，其中1例患者为5’末端上游第6个碱基C缺失(1489-6 del C)，推测该突变可能导致剪切错误；1例患者为错义突变1559T→A(L520Q)，这两例患者的母亲均为杂合突变。另1例患者为1548G→A(L516L)的同义突变。结论 首次报告了中国大陆ALD患者ABCD1基因突变．第6外显子无大片段缺失和重组突变。同一血缘族中可有不同的表型存在，提示是否有其它遗传或环境因素参与表型的表达。通过DNA测序方法亦证实其中2例患者之母为ABCD1基因的杂合子。     

General Aspects and Neuropathology of X‐Linked Adrenoleukodystrophy

X‐adrenoleukodystrophy (X‐ALD) is a metabolic, peroxisomal disease affecting the nervous system, adrenal cortex and testis resulting from inactivating mutations in ABCD1 gene which encodes a peroxisomal membrane half‐adenosine triphosphate (ATP)‐binding cassette transporter, ABCD1 (or ALDP), whose defect is associated with impaired peroxisomal β‐oxidation and accumulation of saturated very long‐chain fatty acids (VLCFA) in tissues and body fluids. Several phenotypes are recognized in male patients including cerebral ALD in childhood, adolescence or adulthood, adrenomyeloneuropathy (AMN), Addison''s disease and, eventually, gonadal insufficiency. Female carriers might present with mild to severe myeloneuropathy that resembles AMN. There is a lack of phenotype–genotype correlations, as the same ABCD1 gene mutation may be associated with different phenotypes in the same family, suggesting that genetic, epigenetic, environmental and stochastic factors are probably contributory to the development and course of the disease. Degenerative changes, like those seen in pure AMN without cerebral demyelination, are characterized by loss of axons and secondary myelin in the long tracts of the spinal cord, possibly related to the impaired lipid metabolism of VLCFAs and the associated alterations (ie, oxidative damage). Similar lesions are encountered following inactivation of ABCD1 in mice (ABCD1 ^‐). A different and more aggressive phenotype is secondary to cerebral demyelination, very often accompanied by inflammatory changes in the white matter of the brain and associated with activation of T lymphocytes, CD1 presentation and increased levels of cytokines, γ‐interferon, interleukin (IL)‐1α, IL‐2 and IL‐6, Granulocyte macrophage colony‐stimulating factor (GM‐CSF), tumor necrosis factor‐α, chemokines and chemokine receptors.     

Microarray comparative genomic hybridization (CGH)-based prenatal diagnosis for chromosome abnormalities using cell-free fetal DNA in amniotic fluid

Cell-free fetal DNA (cffDNA) in the supernatant of amniotic fluid, which is usually discarded, can be used as a sample for prenatal diagnosis. For rapid prenatal diagnosis of frequent chromosome abnormalities, for example trisomies 13, 18, and 21, and monosomy X, using cffDNA, we have developed a targeted microarray-based comparative genomic hybridization (CGH) panel on which BAC clones from chromosomes 13, 18, 21, X, and Y were spotted. Microarray-CGH analysis was performed for a total of 13 fetuses with congenital anomalies using cffDNA from their uncultured amniotic fluid. Microarray CGH with cffDNA led to successful molecular karyotyping for 12 of 13 fetuses within 5 days. Karyotypes of the 12 fetuses (one case of trisomy 13, two of trisomy 18, two of trisomy 21, one of monosomy X, and six of normal karyotype) were later confirmed by conventional chromosome analysis using cultured amniocytes. The one fetus whose molecular-karyotype was indicated as normal by microarray CGH actually had a balanced translocation, 45,XY,der(14;21)(q10;q10). The results indicated that microarray CGH with cffDNA is a useful rapid prenatal diagnostic method at late gestation for chromosome abnormalities with copy-number changes, especially when combined with conventional karyotyping of cultured amniocytes.     

应用双侧扩增阻滞突变系统排除肾上腺脑白质营养不良分子诊断中假基因的干扰

目的应用扩增阻滞突变系统（amplification refractory mutation system, ARMS）排除ABCD1假基因的干扰，对肾上腺脑白质营养不良（adrenoleukodystrophy，ALD）家系进行基因突变分析。方法按ARMS引物设计原则设计上游引物（正常引物、突变引物）和下游公共引物，对家系成员的基因组DNA分别进行PCR扩增。结果R617C突变患者及其母亲的突变引物均扩增出特异性条带（107bp），患者父亲和对照则未见条带，在基因组DNA水平证实了R617C突变的存在。结论双侧ARMS方法可以快速、有效地排除假基因干扰。