Apolipoprotein E genotype analysis in Chinese Han ethnic children with Wilson's disease, with a concentration on those homozygous for R778L

Wilson's disease (WD) is an autosomal recessive disorder of copper metabolism caused by a large number of different mutations in the ATP7B gene. R778L mutation is mostly observed in Chinese, Japanese and Korean patients, whereas the H1069Q point mutation in the ATP7B gene is the most frequent mutation in European patients with WD. In our previous study we did not find a significant correlation between genotype and phenotype (age of onset and clinical presentation) in patients homozygous (37 patients) or heterozygous (52 patients) for R778L. It was reported that European patients homozygous for H1069Q who were also homozygous for the ApoE genotype ε3/3 developed clinical symptoms 5–11 years later than did patients with genotypes other than ApoE ε3/3. In the present study (i) we firstly observed that ApoE ε3/3 did not delay the onset of WD; (ii) no association between ApoE genotype and WD clinical presentation in Chinese Han children, including those patients homozygous for R778L. Thus we conclude that the onset of WD in Chinese children is not related to ApoE ε3/3, although the high frequency of ApoE ε3/3 in Chinese Han children with WD was not significantly different from that in controls.     

A novel deletion mutation within the carboxyl terminus of the copper-transporting ATPase gene causes Wilson disease

In patients with Wilson disease (WD), an autosomal recessive disorder, toxic accumulation of copper results in fatal liver disease and irreversible neuronal degeneration. ATP7B, the gene mutated in WD, contains 21 exons and encodes a copper-transporting ATPase. In this study, all exons of the ATP7B gene of nine WD patients were screened for alterations by conventional mutation detection enhancement (MDE) heteroduplex analysis, followed by direct sequencing of the regions that showed heteroduplex formation. For the first time, a novel deletion mutation (4193delC) in exon 21, causing a frameshift leading to premature truncation of the protein was detected in four of nine patients. The 4193delC removes several signals within the carboxyl terminal domain that may disrupt trafficking of ATP7B protein through trans-Golgi network at the cellular level.     

Deficiency of mitochondrial ATP synthase of nuclear genetic origin

We present clinical and laboratory data from 14 cases with an isolated deficiency of the mitochondrial ATP synthase (7–30% of control) caused by nuclear genetic defects. A quantitative decrease of the ATP synthase complex was documented by Blue-Native electrophoresis and Western blotting and was supported by the diminished activity of oligomycin/aurovertin-sensitive ATP hydrolysis in fibroblasts (10 cases), muscle (6 of 7 cases), and liver (one case). All patients had neonatal onset and elevated plasma lactate levels. In 12 patients investigated 3-methyl-glutaconic aciduria was detected. Seven patients died, mostly within the first weeks of life and surviving patients showed psychomotor and various degrees of mental retardation. Eleven patients had hypertrophic cardiomyopathy; other clinical signs included hypotonia, hepatomegaly, facial dysmorphism and microcephaly. This phenotype markedly differs from the severe central nervous system changes of ATP synthase disorders caused by mitochondrial DNA mutations of the ATP6 gene presenting mostly as NARP and MILS.     

Genetic defects in Indian Wilson disease patients and genotype–phenotype correlation

Wilson disease (WD) is caused by defects in ATP7B gene due to impairment of normal function of the copper transporting P-type ATPase. This study describes a comprehensive genetic analysis of 199 Indian WD patients including mutations detected in our previous studies, undertakes functional assessment of the nucleotide variants in ATP7B promoter and correlates genotype with disease phenotype. The patient cohort harbors a total of 10 common and 48 rare mutations in the coding region of ATP7B including 21 novel changes. The common mutations represent 74% of characterized coding mutant alleles with p.C271X (63/260) and p.G1101R (7/31) being the most prevalent in eastern and western Indian patients, respectively. The mutation spectrum between east and west is mostly different with only three mutations (p.G1061E, p.N1270S and p.A1049A-fs) being shared between both the groups. Eight novel and 10 reported variants have been detected in the promoter and non-coding regions (5′ and 3′UTRs) of ATP7B. Promoter reporter assay demonstrated that 3 novel variants and 5 reported polymorphisms alter the gene expression to a considerable extent; hence might play important role in ATP7B gene regulation. We devised the neurological involvement score to capture the spectrum of neurological involvement in WD patients. By utilizing the age at onset, neurological involvement score and ATP7B mutation background, we generated a genotype–phenotype matrix that could be effectively used to depict the phenotypic spectra of WD affected individuals and serve as a platform to identify prospective “outliers” to be investigated for their remarkable phenotypic divergence.     

Defective roles of ATP7B missense mutations in cellular copper tolerance and copper excretion

Wilson's disease (WD) is a hereditary disorder of copper metabolism resulting from mutations within ATP7B. Clinical investigations showed that ATP7B missense mutations cause a wide variety of symptoms in WD patients, which implies that those mutations might affect ATP7B function in a number of ways and each would have deleterious consequences on normal copper distribution and lead to WD. Nonetheless, it is still unknown about the influences of those mutations on ATP7B function of increasing copper excretion and enhancing cellular copper tolerance. Here we established the stable expression cell lines of wild-type (WT) ATP7B and its four missense mutants (R778L, R919G, T935M and P992L), tested cellular copper tolerance and copper excretion using those cell lines, and also observed cellular distribution of WT ATP7B proteins and those mutants in transiently transfected cells. We found that extrinsic expressing WT ATP7B reduced CuCl₂-induced copper accumulation and enhanced cellular copper tolerance by accelerating copper excretion, which was selectively compromised by R778L and P992L mutations. Further investigation showed that R778L mutation disrupted the subcellular localization and trafficking of ATP7B proteins, whereas P992L mutation only affected the trafficking of ATP7B. This indicates that ATP7B missense mutants have distinct effects on cellular copper tolerance.     

应用限制性酶谱分析法快速检出Wilson病基因突变热点

目的建立Wilson病（WD）基因突变热点的快速检出方法，并探讨其在WD临床可疑患者诊断中的价值。方法PCR扩增我国WD基因的突变热区──第8号和12号外显子，分别以限制性内切酶MspI和TaiI消化扩增产物，2％琼脂糖凝胶电泳分离，得出相应限制性酶切图谱并进行分析。56例非同源家系的WD患者及60例正常对照进行了该项检测。其中44例同时进行这两个外显子的测序检测。结果37．5％（21／56）的WD患者在第8号外显子检测到Arg778Leu／Gln点突变，其中12例为纯合点突变，9例为杂合点突变，染色体突变频率为29．5％（33／112）。16．1％（9／56）的患者在第12号外显子检测到Thr935Met点突变，均为杂合点突变，染色体突变频率为8．0％（9／112）。结果与测序相符。结论采用限制性酶谱分析法可准确检出WD基因最常见的两个突变点，有助于对临床可疑患者进行诊断。并具有简便快速、结果清晰可靠、不需用同位素等优点，易于推广应用。     

p.H1069Q mutation in ATP7B and biochemical parameters of copper metabolism and clinical manifestation of Wilson's disease.

We compared the effect of the p.H1069Q mutation and other non-p.H1069Q mutations in ATP7B on the phenotypic expression of Wilson's disease (WD), and assessed whether the clinical phenotype of WD in compound heterozygotes depends on the type of mutation coexisting with the p.H1069Q. One hundred forty-two patients with clinically, biochemically, and genetically diagnosed WD were studied. The mutational analysis of ATP7B was performed by direct sequencing. A total number of 26 mutations in ATP7B were identified. The p.His1069Gln was the most common mutation (allelic frequency: 72%). Seventy-three patients were homozygous for this mutation. Of compound heterozygotes, 37 had frameshift/nonsense mutation, and 20 had other missense mutation on one of their ATP7B alleles. Twelve patients had two non-p.H1069Q mutations. Patients homozygous for the p.H1069Q mutation had the less severe disturbances of copper metabolism and the latest presentation of first WD symptoms. The most severely disturbed copper metabolism and the earliest age at initial disease manifestation was noticed in non-p.H1069Q patients. In compound heterozygotes, the type of mutation coexisting with the p.H1069Q to a small extent influenced WD phenotype. The phenotype of WD varied considerably among patients with the same genotype. The p.H1069Q mutation is associated with late WD manifestation and with a mild disruption of copper metabolism. In compound heterozygotes, the phenotype of WD to a small extent depends on the type of mutation coexisting with the p.H1069Q. Besides genotype, additional modifying factors seem to determine WD manifestations.     

A clinical and genetic study of 56 Saudi Wilson disease patients: identification of Saudi-specific mutations

Wilson disease (WD) is a hereditary disorder, with recessive transmission and genetic heterogeneity. Several mutations of ATP7B, the gene underlying WD, were reported in many ethnic groups. In this study, mutation screening in ATP7B of 56 Saudi Arabian WD patients was undertaken. The clinical data of all patients were recorded. The entire ATP7B coding sequence, including intron-exon boundaries were screened for mutation by the polymerase chain reaction (PCR)-based mutation detection technique and DNA sequencing. Thirty-nine patients were symptomatic at presentation and 17 subjects were pre-symptomatic siblings of affected patients. Fourteen patients had neurological, 11 patients had mixed (hepatic and neurological), and 14 patients had hepatic presentations. Family history suggestive of WD was present in 72% of cases and 68% had consanguineous parents. Genetic analysis showed disease-causing mutations in three exons (exons 8, 19 and 21) of the ATP7B gene in 28 patients (50%). Mutations in exons 21 (18 cases) and 19 (one case) were unique for Saudis. This large series of Saudi patients with WD has shown wide variability in the genomic substrate of WD. There is no correlation between genotype and clinical presentation.     

74例肝豆状核变性患者中ATP7B基因七种新突变的发现

目的 分析中国人肝豆状核变性（Wilson disease,WD）患者ATP7B基因突变的分布特征,建立利用变性高效液相色谱（DHPLC）技术对Wilson病进行基因诊断的方法,并评价其在临床的应用价值.方法 对临床确诊为Wilson病的74例患者及50名健康人抽取外周静脉血提取基因组DNA.以患者和健康人的DNA为模板,分别对ATP7B基因的21个外显子进行PCR扩增.取PCR产物应用DHPLC技术在部分变性条件下检测突变并DNA测序证实突变位点.结果 利用DHPLC技术筛查并经测序证实,共发现22种ATP7B基因突变类型,其中7种是新发现的,同时发现11种多态,其中3种是新发现的.第8外显子Arg778Leu突变率最高,其频率为25.0%.其次,2356-2A＞G突变频率为3.4%,Arg919Gly突变频率为2.7%,其他外显子突变频率均在1.0%～2.0%之间.结论 中国人的WD基因突变具有多样性特点,热点突变是第8外显子Arg778Leu.DHPLC具有高通量、敏感、准确且经济的特点,适合于大样本的筛查且能够发现未知的突变,是一种有临床应用价值的基因诊断技术.     

PDE4B polymorphisms and decreased PDE4B expression are associated with schizophrenia

Schizophrenia has a complex genetic underpinning and variations in a number of candidate genes have been identified that confer risk of developing the disorder. We report in the present studies that several single nucleotide polymorphisms (SNPs) and a two-SNP haplotype in PDE4B are associated with an increased incidence of schizophrenia in two large populations of Caucasian and African American patients. The SNPs in PDE4B associated with schizophrenia occur in intronic sequences in the vicinity of a critical splice junction that gives rise to the expression of PDE4B isoforms with distinct regulation and function. We also observed specific decreases in phosphodiesterase 4B (PDE4B) isoforms in brain tissue obtained postmortem from patients diagnosed with schizophrenia and bipolar disorder. PDE4B metabolically inactivates the second messenger cAMP to regulate intracellular signaling in neurons throughout the brain. Thus, the present observations suggest that dysregulation of intracellular signaling mediated by PDE4B is a significant factor in the cause and expression, respectively, of schizophrenia and bipolar disorder and that targeting PDE4B-regulated signaling pathways may yield new therapies to treat the totality of these disorders.     

Positive association between SIAT8B and schizophrenia in the Chinese Han population

The Sialyltransferase 8B gene (SIAT8B) is located at 15q26, a susceptibility region for both schizophrenia and bipolar disorder. The protein encoded by this gene has an important role in neural development and sialic acid synthesis on the neural cell adhesion molecule (NCAM). Previous research had indicated that the promoter region of SIAT8B is associated with schizophrenia in the Japanese population. To take this further we carried out an association study based on 643 unrelated schizophrenics and 527 unrelated healthy subjects, all Han Chinese, recruited from Shanghai. Although our results differed from those of the Japanese research, rs3759915, also located in the promoter region of SIAT8B, showed nominally significant association with schizophrenia (P = 0.0036). Moreover, haplotypes constructed from rs3759915 and another two SNPs reported in the Japanese study (rs3759914 and rs3759916, also located in promoter region of SIAT8B) which located in the same LD block were significantly associated with schizophrenia (global P = 0.0000050). Our findings indicate that SIAT8B may be a candidate susceptibility gene for schizophrenia in the Chinese Han population and may also provide further support for the potential importance of polysaccharide-synthesizing genes in the etiology of schizophrenia.     

Sensory ataxia as a prominent clinical presentation in three families with mutations in CYP7B1

Pathogenic mutations in CYP7B1 account for SPG5, an autosomal recessive hereditary spastic paraplegia characterized by a complex phenotype including visual problems and cerebellar dysfunction. Sensory ataxia is not usually regarded as a typical clinical feature of SPG5. The purpose of this study was to describe six patients showing features of sensory ataxia as the prominent and/or initial symptoms of SPG5. Six patients from three distinct pedigrees (three women, three men; age 49.5 ± 18.2 years), all presenting gait unsteadiness and frequent falls since childhood, underwent clinical and molecular investigations. All showed marked sensory ataxic gait with positive Romberg's sign, as well as severely impaired position and vibration sense. Comparatively minor signs of pyramidal involvement were also detected. In four of the patients, brain MRI showed white matter hyperintensities on T2-weighted images. An already reported homozygous c.889A>G (p.T297A) mutation in SPG5/CYP7B1 was found in five patients from two families, whereas the remaining case harbored the novel c.250_251delC/p.L84Ffs*6 and c.266A>C/p.Y89S variants. Marked and enduring sensory ataxia can be a pivotal sign in SPG5, and expands the phenotypic spectrum associated with mutations in CYP7B1.     

Identification of a high frequency of mutation at exon 8 of the ATP7B gene in a Chinese population with Wilson disease by fluorescent PCR.

BACKGROUND: Wilson disease (WD) is an autosomal recessive disorder of copper transport. Mutation analysis has led to the discovery of more than 100 mutations at ATP7B, and most of them are population specific. OBJECTIVES: To verify the high frequency of mutation at exon 8 of ATP7B in Chinese patients with WD and to establish a DNA diagnostic method for WD. SETTING: University medical centers. PATIENTS AND METHODS: Screening for mutations at exon 8 of ATP7B by fluorescent polymerase chain reaction analysis and restriction analysis was conducted in 106 unrelated Chinese patients with WD and in 55 individuals from 10 Chinese families with WD. RESULTS: Five homozygotes and 32 heterozygotes were identified. Sequence analysis showed a missense mutation (2273G-->T) and a nonsense mutation (2250C-->G) together at exon 8. The rate of gene mutation in 106 patients was 35% (5% homozygous and 30% heterozygous). Samples of DNA from 55 individuals from 10 Chinese families with WD were examined by fluorescent polymerase chain reaction. We found that 13 siblings were carriers (24%). CONCLUSIONS: A high frequency of mutation at exon 8 of the ATP7B gene exists in the Chinese population, and fluorescent polymerase chain reaction analysis may be an effective and accurate assay in detection of the WD gene.     

A novel COMMD1 mutation Thr174Met associated with elevated urinary copper and signs of enhanced apoptotic cell death in a Wilson Disease patient

Wilson disease (WD) results from accumulation of copper and caused due to mutations in ATP7B, a copper transporting ATPase. Besides regular hepatic and neurological symptoms, WD patients occasionally manifest atypical symptoms due to unknown cause. To understand the molecular etiology of atypical WD manifestations, we screened COMMD1, a gene implicated in canine copper toxicosis, in 109 WD patients including those with atypical symptoms. In a patient showing apoptotic symptoms and high urinary copper surpassing normal WD levels, we identified a novel, putative mutation in COMMD1. Two other changes were also identified in the gene. We have examined genotype-phenotype correlation between the detected changes and the atypical presentation of the WD patient.     

Mutation analysis and the correlation between genotype and phenotype of Arg778Leu mutation in chinese patients with Wilson disease

BACKGROUND: The defective gene (ATP7B) that causes Wilson disease (WD) codes for a putative copper-transporting P-type adenosine triphosphatase. After cloning of ATP7B, the spectrum of mutations and their clinical consequences have been investigated in patients with WD in different ethnic populations. However, the spectrum of mutations and the correlation of genotype-phenotype in the Chinese population have not been extensively studied. OBJECTIVE: To investigate the characterization of mutations of ATP7B and the correlation between genotype and phenotype in the Chinese population. METHODS: We studied 60 unrelated healthy Chinese and 65 unrelated Chinese families, including 84 patients with WD and 126 parents. Genomic DNA was prepared from peripheral blood leukocytes using a salt-precipitation method. Polymerase chain reaction single-strand conformation polymorphism and subsequent direct sequencing were used to identify the mutations and polymorphisms of ATP7B. Statistical analysis was performed using t test or chi(2) test. RESULTS: We identified 18 mutations (7 novel) and 11 polymorphisms (3 novel). The novel mutations are -36C-->T, Trp650ter, Gln914ter, 2810delT, Thr935Met, Arg1041Pro, and Glu1173Lys. The novel polymorphisms are 1168A-->G (Ile390Val), 2785A-->G (Ile929Val), and 3316G-->A (Val1106Ile). Two mutations, Arg778Leu and Thr935Met, are relatively frequent, representing 37.7% and 10.0% of patients, respectively. To our knowledge, we are the first to report the correlation between the genotype and phenotype of Arg778Leu. The result shows that Arg778Leu homozygotes are associated with the early onset of WD with hepatic presentation. CONCLUSIONS: The Arg778Leu and Thr935Met mutations are hot spots in the Chinese population. The features of mutations of ATP7B differ between the Chinese and Western ethnic populations. The Arg778Leu mutation has severe effects on the function of ATP7B. These findings are valuable for developing a fast and effective method to diagnose the presence of the WD gene.     

Genetic analysis of the gene coding for DARPP-32 (PPP1R1B) in Japanese patients with schizophrenia or bipolar disorder

Several lines of evidence, including genome-wide linkage scans and postmortem brain studies of patients with schizophrenia or bipolar disorder, have suggested that DARPP-32 (dopamine- and cAMP-regulated phosphoprotein, 32 kDa), a key regulatory molecule in the dopaminergic signaling pathway, is involved in these disorders. After evaluating the linkage disequilibrium pattern of the gene encoding DARPP-32 (PPP1R1B; located on 17q12), we conducted association analyses of this gene with schizophrenia and bipolar disorder. Single-marker and haplotypic analyses of four single nucleotide polymorphisms (SNPs; rs879606, rs12601930, rs907094, and rs3764352) in a sample set (subjects with schizophrenia = 384, subjects with bipolar disorder = 318, control subjects = 384) showed that PPP1R1B polymorphisms were not significantly associated with schizophrenia, whereas, even after Bonferroni corrections, significant associations with bipolar disorder were observed for rs12601930 (corrected genotypic p = 0.00059) and rs907094 (corrected allelic p = 0.040). We, however, could not confirm these results in a second independent sample set (subjects with bipolar disorder = 366, control subjects = 370). We now believe that the significant association observed with the first sample set was a result of copy number aberrations in the region surrounding these SNPs. Our findings suggest that PPP1R1B SNPs are unlikely to be related to the development of schizophrenia and bipolar disorder in the Japanese population.     

Identification of vasopressin in the subfornical organ region: effects of dehydration

The subfornical organ (SFO), a neuroendocrine structure implicated in salt-water homeostasis, contains secretory structures histochemically similar to those in the neurohypophysis. Because of these morphological similarities, we compared levels of vasopressin (VP) in the SFO area and the adjacent hippocampal commissure-fornix (HC-F) of normally hydrated and 48 h water-deprived (WD) rats. VP in the SFO region from normally hydrated rats was 44 ± 5pg/mg protein, 3.5 +- 0.4ng/g wetw eight or 3.6 ± 0.4pg/SFO. These concentrations increased (P < 0.05) about two-fold after WD. The content of VP, ng/g wet weight, in HC-F was higher (P < 0.05) than the SFO area and also increased (P < 0.05) after WD. VP was detected in other fiber tracts, anterior commissure (AC) and fornix (F), but was unchanged by WD. Changes in hormone observed in the SFO and HC-F regions were therefore not part of a generalized increase of VP in the brain, nor can they be ascribed to elevated plasma levels. Thus, VP changes in the SFO region may be functionally significant and related to an SFO endocrine role in hydration. VP in fiber tracts (F, AC) unassociated with the hypothalamo-hypophysial system and unchanged after WD may suggest an unidentified role of this hormone in the central nervous system.     

3个肝豆状核变性家系的分子遗传学分析及临床运用研究

目的 探讨运用基因分析协助快速诊断、精准治疗肝豆状核变性(Wilson's disease,WD)的价值。方法 临床上收集、鉴定3个无血缘关系的常染色体隐性WD家系,抽取家系成员的外周血样本并提取基因组DNA; 利用Sanger测序分别对3个家系先证者的WD致病基因ATP7B的全部21个外显子以及外显子-内含子交接区域进行突变检测; 结合文献分析突变基因在不同种族的突变率,高频突变基因型与临床表型、发病早晚、病情严重程度的关系; 根据基因型制定“基因导向型”治疗方案,评估患者1年后的疗效。结果 WD具有临床表型的异质性和遗传异质性; 家系1中发现ATP7B的2个复合杂合突变c.2333G>T(p.R778L)、c.2975C>T(p.P992L); 家系3中发现ATP7B的1个杂合突变p.R778L,家系3可能存在还未发现的ATP7B基因突变; 家系2未能在遗传学上确定致病原因,提示可能存在还未发现的新的WD致病基因或常规测序手段无法发现的ATP7B基因突变; 根据基因型制定“基因导向型”治疗方案,对家系1和家系3的患者具有有效的治疗效果。结论 基于ATP7B的基因分析断有助于快速确诊肝豆状核变性,“基因导向型”治疗方案成功运用为该疾病的精准治疗提供了一定的依据,也为分子遗传学技术临床运用的推广和普及奠定了基础。     

Novel ATP7B gene mutations in Chinese Han patients with hepatolenticular degeneration

BACKGROUND: ATP7B gene exon 8 Arg778Leu and exon 12 Arg952Lys are gene mutation hot spots in Chinese Han patients with hepatolenticular degeneration, or Wilson's disease (WD). However, the gene fragments are too short for detection and the mutation detection rate remains low.OBJECTIVE: To analyze DNA sequences of ATP7B gene exon 8-exon 9 and exon 10-exon 12 sections. DESIGN, TIME AND SETTING: A concurrent, non-randomized, controlled, genetic polymorphism study was performed at the Anhui Medical Genetics Center, Anhui, China from March to July in 2009.PARTICIPANTS: Fifty patients, who were admitted to the Department of Neurology at the First Affiliated Hospital of Anhui Traditional Chinese Medical College between March and July in 2009, were diagnosed with WD. The WD group comprised 32 males and 18 females, with an average age of (18.8 ± 8.3) years. WD was confirmed by clinical observation, as well as physical, imaging, and biochemical examinations, including testing for serum copper, ceruloplasmin, and copper oxidase. The control group comprised 20 normal subjects, who underwent physical examination at the First Affiliated Hospital of Anhui Traditional Chinese Medical College, and included 13 males and 7 females, with an average age of (27.9 ± 2.4) years. All subjects were Chinese Han population.METHODS: Genomic DNA was extracted from 50 WD patients and 20 normal controls. Polymerase chain reaction amplification of ATP7B gene exon 8-exon 9 (about 1 100 bp) and exon 10-exon 12 (about 850 bp) segments was performed. DNA exon-intron amplification products from all subjects were processed through direct bidirectional sequencing, and sequencing results were analyzed. MAIN OUTCOME MEASURES: Sequence changes of ATP7B gene exon 8-exon 9 and exon 10-exon 12 segments.RESULTS: In the 50 included WD patients, ATP7B gene intron 8 nt53592A → G with nt53671G → A homozygous mutation was detected between exon 8-exon 9 in seven cases; exon 8 Arg778Leu mutations with Leu770Leu synonymous mutation was detected in four cases; exon 11 Gly790Arg heterozygous missense mutation between exon 10-exon 12 was found in four cases; exon 12 Arg952Lys heterozygous missense mutation was seen in 11 cases; and two additional cases were associated with exon 12IIe929Val polymorphism.CONCLUSION: ATP7B gene intron 8 mutation is a possible pathogenic mutation that is associated with WD pathogenesis. The exon 11 mutation rate accounts for 8% of all WD patients, and the very few previously reported cases deserve further study.     

中国人肝豆状核变性基因（ATP7B）第16号外显子的突变特征

为探讨中国人肝豆状核变性基因（ATP7B）第16号外显子的突变特征，应用聚合酶链反应-单链构象多态（PCR－SSCP）技术对无亲缘关系的44例肝豆状核变性患者和60名正常人的ATP7B基因第16号外显子，进行了突变及多态的筛查。发现3例患者具有与正常对照不同的单链构象，进一步经DNA测序证实其中2例发生了Ileull48Thr突变，另回例发生Glull73Lys突变。上述突变均为国际上未报道过的新型错上突变。此外，还发现2种多态现象，其中Valll40Ala与文献报道一致，而3498C—T的改变则是一种本报道过的新多态、表明中国人ATP7B基因第16号外星子的突变性质与西方人具有差异性。