Plasminogen with type-I mutation in the Chinese Han population

A functionally inactive plasminogen (PLG) variant, PLG M5, is polymorphic in the Japanese population and has a codon 601 mis-sense mutation (GCT for Ala to ACT for Thr), designated type-I mutation. The present study aimed to reveal whether the plasminogen with type-I mutation is present in the Chinese Han population. Among 104 healthy Chinese students, phenotype PLG AM5 was found in three subjects (2.9%), while 100 subjects were phenotype A and one was phenotype AA3. In the three subjects with PLG AM5, plasma concentrations of immunoreactive PLG were normal but PI G activities were decreased. Analysis using PCR and dot-blot hybridization with allele-specific oligonucleotide probes revealed the presence of the type-I mutation in the PLG gene of all three subjects with PLG AM5. The data indicate that PLG with type-I mutation is present in the Chinese Han population, possibly at a polymorphic frequency.     

Prevalence of the C282Y mutation for haemochromatosis on the Island of Majorca

The C282Y mutation of the HFE gene has been reported to be present in most of the patients with hereditary haemochromatosis (HH) of Northern European ancestry. HH affects approximately 1/300 individuals, but it is not evenly distributed in the different European countries. In the present study, polymerase chain reaction (PCR) and restriction-enzyme digestion were used to analyse the frequency of the most important mutation in haemochromatosis (C282Y) in subjects from Majorca (Balearic Islands, Spain) and patients with haemochromatosis. The results were compared with other studies from Spain and Europe. A total of 420 Majorcan chromosomes were analysed and the C282Y mutation was observed at a frequency of 2.62%+/-0.8 (11 heterozygotes: eight men and three women). In the group of hereditary haemochromatosis probands, 13 out of 14 were homozygous for the C282Y mutation. In the distribution of the C282Y mutation, a north-west to south-east cline was detected, supporting the Celtic origin of this mutation.     

Segregation of the fragile X mutation from an affected male to his normal daughter.

We report here a family in which the fragile X mutation segregates from an affected grandfather through his normal daughter to an affected grandson. The grandson shows clinical and cytogenetic expression of fragile X syndrome due to a full mutation (large methylated insertion) in the fragile X gene (FMR-1). The mother shows a premutation (small unmethylated insertion) in her FMR-1 gene as the sole manifestation of the fragile X syndrome. The grandfather expresses the fragile X syndrome at the clinical and cytogenetic level, whereas he is mosaic for a methylated full mutation and an unmethylated premutation. The absence of expression of the fragile X mutation when transmitted through an expressing male might present further evidence for genomic imprinting of the FMR-1 gene. Alternatively, it is possible that the grandfather transmitted his premutation to his daughter due to germline mosaicism with both the premutation and the full mutation present in his sperm.     

The common mitochondrial DNA deletion deltamtDNA(4977): shedding new light to the concept of a tumor suppressor mutation

We propose that the age-related accumulation of deltamtDNA(4977) mutations may serve a protective function against tumor-promoting effects of other somatic mutations. The evidence discussed here is consistent with the concept that deltamtDNA(4977) plays a tumor-suppressor role, thus shedding new light to the concept of a tumor suppressor mutation. This concept may help understand how a tumor-promoting mutation may be able to cause malignant transformation in cells lacking a tumor-suppressor mutation, while the same tumor-promoting mutation can be present in cells that carry a tumor-suppressor mutation, without causing cancer.     

Gaucher disease: N370S glucocerebrosidase gene frequency in the Portuguese population

In the Portuguese population the most frequent form of Gaucher disease is type 1. The N370S glucocerebrosidase gene mutation accounts for 63% of mutated alleles. The frequency of this mutation was accurately determined in the Portuguese population, which does not present an Ashkenazi Jewish genetic background. A gene frequency of 0.0043, with 95% confidence limits between 0.0023 and 0.0063, was obtained studying the genomic DNA of 2000 blood cards randomly sampled from the national neonatal screening program. On the basis of this frequency a significantly high number of homozygotes for the N370S mutation should be expected in the Portuguese population. This finding supports the idea that the majority of homozygotes for this mutation present a very mild clinical phenotype and remain undiagnosed.     

Analysis of mitochondrial DNA in Leber''s hereditary optic neuropathy.

Twenty-eight patients from 25 maternal lineages with Leber's hereditary optic neuropathy (LHON) were investigated by restriction enzyme analysis for the presence or absence of the point mutation described by Wallace et al. The mutation was identified in 18 of 25 (72%) families with LHON. This provides further evidence that this mutation is present in the majority of patients with LHON. In 19 of these families with LHON, additional analysis using sequencing, oligonucleotide probing, and competitive oligonucleotide priming of PCR products was performed. In 14 cases with the site loss the point mutation was present, and five without the site loss had the wild type sequence in this region.     

Clinical and pathological features of an Alzheimer's disease patient with the MAPT Delta K280 mutation

We identified a case of Alzheimer's disease with a deletion of the lysine residue at codon 280 (DeltaK280) in exon 10-encoded microtubule-binding repeat domain of the tau gene (MAPT). This mutation was originally identified in a sporadic case of frontotemporal dementia (FTD) with a family history of Parkinson's disease. In the original report, the authors were careful in their assessment of the pathogenicity and suggested one could not be sure whether the mutation was pathogenic or not. The mutation has always presented a conundrum because it is the only known mutation, of assumed pathogenicity, which increases the proportion of 3-repeat tau mRNA in in vitro assays. Here we present the clinical and pathological features of a new case with this mutation and discuss whether the mutation is indeed pathogenic.     

Molecular and clinical characterization of a Moroccan Cog7 deficient patient

Mutations in the N-linked glycosylation pathway cause rare autosomal recessive defects known as Congenital Disorders of Glycosylation (CDG). A previously reported mutation in the Conserved Oligomeric Golgi complex gene, COG7, defined a new subtype of CDG in a Tunisian family. The mutation disrupted the hetero-octomeric COG complex and altered both N- and O-linked glycosylation. Here we present clinical and biochemical data from a second family with the same mutation.     

PTEN hamartoma tumor syndrome and Gorham-Stout phenomenon

PTEN: hamartoma tumor syndrome (PHTS) is a group of syndromes caused by mutations in PTEN. Gorham-Stout phenomenon (GSP) is a rare condition characterized by proliferation of vascular structures in bones, resulting in progressive osteolysis. Here we present a 1-year-old boy with PHTS and GSP. The lesion that later proved to be GSP was evident from the age of 4 months, and became symptomatic at the age of 1 year. Eventually, he developed a fatal chylothorax. Mutation analysis revealed a germline heterozygous mutation c.517 C>T (p.Arg173Cys) in exon 6 of PTEN. Analysis of the lymphatic malformation (LM) tissue revealed no loss of heterozygosity (LOH) nor a second, somatic PTEN mutation of the remaining wild type allele. The germline p.Arg173Cys mutation was also present in the mother and the propositus' younger sister and brother. Further molecular work-up showed a heterozygous variant c.2180C>T (p.Ala727Val) FLT4 in the LM tissue, which was also present in the germline of mother and two siblings. GSP has not been reported before in a patient with a PTEN mutation. Up to this date, this mutation is the only genetic defect possibly involved in the etiology of GSP which is plausible given the known function of PTEN in angiogenic signaling.     

Mutations of the BRAF gene in papillary thyroid carcinoma and in Hashimoto's thyroiditis

The purpose of the present study was to investigate the frequency of BRAF mutations in human papillary thyroid carcinoma (PTC) and Hashimoto's thyroiditis (HT) and to evaluate the association of the BRAF mutation with the clinicopathological features of both of these thyroid disorders. A total of 51 PTC with no HT, 28 PTC with HT and 27 HT with no PTC were evaluated using DNA extracted from paraffin-embedded specimens. BRAF mutations were analyzed by direct DNA sequencing of the polymerase chain reaction (PCR)-amplified exon 15. The BRAF missense mutation at codon 599 (T1796A) was present in 46 of 51 PTC (90%) with no HT, 18 of 28 PTC (64%) with HT, four of 28 HT (14%) with PTC, and zero of 27 HT with no PTC. The BRAF mutation at codon 600 (A1798G) was not detected in any case. Clinicopathological examination of 106 patients with either PTC or HT showed that the BRAF mutation was significantly correlated with patient age. These data indicate that the BRAF mutation is associated with a valuable biological property of PTC and may participate in the pathogenesis of PTC arising in HT. These results indicate that the detection of the BRAF mutation in HT can be helpful for prediction of progress to PTC.     

一个中国近端指(趾)骨间关节黏连家系NOG基因新突变鉴定

目的 检测一个中国近端指(趾)骨间关节黏连家系的致病基因突变.方法 收集该家系患者和家系成员的临床资料,采集外周血提取基因组DNA.运用聚合酶链式反应和Sanger测序法筛查先证者的NOG和GDF5基因.确定突变位点后,在家系成员中进行共分离分析并在200名正常对照中筛查该突变.结果 该家系患者中存在NOG基因c.502 T＞C错义突变,该突变导致其编码蛋白Noggin第168位氨基酸由苯丙氨酸变为亮氨酸(p.F168L).在家系正常成员和200名正常对照中未检测到相同突变.该突变在dbSNP、ExAC等数据库中未见报道.在GDF5基因上未发现可疑突变.结论 NOG基因c.502 T＞C错义突变是该家系发病的原因.     

Mutation analysis of an Ashkenazi Jewish family with Gaucher disease in three successive generations

Seven members of an Ashkenazi Jewish family with Gaucher disease in 3 successive generations were tested for the presence of the 2 common mutations known to occur in the glucocerebrosidase gene. Genomic DNA from blood or skin fibroblasts of relatives was amplified by using the PCR technique and individual mutations identified by oligonucleotides specific to the mutated sequences. Four individuals were homozygous for a mutation at amino acid 370 (370 mutation) known to occur only in type 1 disease. The other 3 affected relatives were compound heterozygotes for this mutation and for a mutation at amino acid 444 (NciI mutation) which, in the homozygous state, is associated with neurological disease. Clinical severity was more marked in the compound heterozygotes than in the homozygotes. Since the mutation is present in Ashkenazim, molecular diagnosis in families which carry the NciI mutation should prove useful in assessing their risk of the neurologic forms of Gaucher disease.     

鸟氨酸氨甲酰基转移酶缺陷症三例临床和基因突变分析

目的 分析鸟氨酸氨甲酰基转移酶缺陷症(ornithine carbamoyltransferase deficiency,OTCD)的临床表现、遗传学特点,从基因水平了解OTCD的致病因素,达到基因诊断和遗传咨询的目的.方法 应用聚合酶链反应扩增3例OTCD患者的鸟氨酸氨甲酰转移酶(ornithine carbamoyltransferase,OTC)基因各个外显子所在片段,并进行直接测序,以检测突变.结果 例1在生后6月以呕吐起病,为错义突变T262I,其母亲表型正常,为T262I杂合突变;例2在2岁时以烦躁不安起病,为错义突变R277W,例2父母未行基因检测;例3以嗜睡在新生儿期起病,为错义突变I172M,其母表型正常,为I172M杂合突变.结论 基因分析是诊断OTCD有效可行的方法.T262I突变及R277W突变是症状较轻的温和突变,I172M突变是起病年龄早及症状重的突变.对致病基因进行突变检测不仅可以诊断OTCD,而且可以发现无症状的基因携带者,为遗传咨询及产前诊断提供依据.

Abstract：

Objective To analyze the clinical and genetic characteristics of three children with ornithine carbamoyltransferase deficiency(OTCD), and to provide a practical method for gene diagnosis and genetic counseling of the disease. Methods All exons of the ornithine carbamoyltransferase (OTC) gene were screened by polymerase chain reaction-DNA direct sequencing in the three OTCD patients. Results One patient firstly presented as vomiting at 6 month of age. A missense mutation of T262I was detected. His mother had the same mutation without any clinical symptoms. The second patient presented as restlessness, and had a missense mutation of R277W. Gene analysis of his parents was not available. The third patient presented as neonatal lethargy, harbored a missense mutation of I172M. His mother had the same mutation without any clinical symptoms. Conclusion Gene mutation analysis is a feasible way for diagnosing OTCD. Patients with I172M mutation present symptom early, while those with T262I and R277W mutations manifest symptoms later. Gene mutation analysis will be important for asymptomatic and prenatal diagnosis and genetic counseling.     

No association between the CNTF null mutation and schizophrenia or personality

The ciliary neurotrophic factor (CNTF) is a neurotrophic cytokine that plays a critical role in neurodevelopment. On the basis of neurodevelopmental hypothesis, the CNTF gene has been a candidate locus for schizophrenia. Several studies have investigated the association between the null mutation of the gene and schizophrenia, however, with inconsistent results. In the present study, we investigated the association in 222 Japanese patients with schizophrenia and 237 controls. The association between the mutation and personality traits was also studied, to investigate the effect of the mutation in participants from the general population. As a result, no association was observed between the mutation and schizophrenia nor personality traits, evaluated by using the Revised NEO Personality Inventory scores. The present study did not provide evidence for the association between the CNTF gene and schizophrenia or personality traits in the Japanese population.     

OPA1基因G401D突变导致常染色体视神经萎缩和听力受损

目的对一个中国视神经萎缩1（optic atrophy 1，0PA1）家系进行临床和基因分析。方法对家系进行连锁分析，通过测序和限制性片段长度多态鉴定致病基因突变。结果在家系患者中均发现OPA1基因的一个错义突变1202（G→A），即G401D，而且患者呈现出视神经萎缩以及听力受损的综合征症状。结论在中国OPA1患者中鉴定了OPA1基因突变，并支持OPA1基因突变可导致伴随有听力受损的视神经萎缩。     

Further evidence that one of the earliest alterations in colorectal carcinogenesis involves APC.

Colorectal cancer is hypothesized to arise after the accumulation of multiple mutations in critical oncogenes or tumor suppressor genes. The relative timing of each mutation is unknown because the exact number and types of mutations differ between tumors. However, for every mutation except the first, tumor heterogeneity must exist until clonal dominance is reestablished. This principle was applied to mutant APC genes in eight colorectal adenomas. The APC mutations were homogeneously present throughout the adenomas, including those less than 1 cm in size, but absent from the normal polyp stalks. In one adenoma with APC and c-K-ras mutations, both mutations were simultaneously present in only a small discrete portion, suggesting that the c-K-ras mutation was acquired after the APC mutation. These findings suggest that when mutations in APC occur, they are usually one of the first events in colorectal carcinogenesis or provide such a strong selective advantage that intratumor heterogeneity is seldom observed.     

mutation3D: Cancer Gene Prediction Through Atomic Clustering of Coding Variants in the Structural Proteome

A new algorithm and Web server, mutation3D ( http://mutation3d.org ), proposes driver genes in cancer by identifying clusters of amino acid substitutions within tertiary protein structures. We demonstrate the feasibility of using a 3D clustering approach to implicate proteins in cancer based on explorations of single proteins using the mutation3D Web interface. On a large scale, we show that clustering with mutation3D is able to separate functional from nonfunctional mutations by analyzing a combination of 8,869 known inherited disease mutations and 2,004 SNPs overlaid together upon the same sets of crystal structures and homology models. Further, we present a systematic analysis of whole‐genome and whole‐exome cancer datasets to demonstrate that mutation3D identifies many known cancer genes as well as previously underexplored target genes. The mutation3D Web interface allows users to analyze their own mutation data in a variety of popular formats and provides seamless access to explore mutation clusters derived from over 975,000 somatic mutations reported by 6,811 cancer sequencing studies. The mutation3D Web interface is freely available with all major browsers supported.     

A previously undescribed frameshift deletion mutation of HFE (c.del277; G93fs) associated with hemochromatosis and iron overload in a C282Y heterozygote

A 62-year-old white man with a hemochromatosis phenotype was found to be heterozygous for the C282Y mutation of the HFE gene. The H63D and S65C mutations of HFE were not present. As most C282Y heterozygotes do not develop a hemochromatosis phenotype, the coding region of the patient's HFE gene was sequenced and a previously undescribed frameshift mutation was identified in exon 2 (c.del277; G93fs) that resulted in a premature stop-codon. There were no coding region mutations of the ferroportin gene (FPN1). We performed human leukocyte antigen (HLA) typing of the patient and his brother who was heterozygous for the C282Y HFE mutation unassociated with a hemochromatosis phenotype. They shared only C282Y and the HLA haplotype A*03, B*14; hence, the c.del277 mutation was linked to the HLA haplotype A*02, B*44 and therefore not on the same chromosome as the C282Y mutation. Thus, the present patient's only intact HFE protein is C282Y, and this may explain his hemochromatosis phenotype.     

Spectrum of CFTR mutations in the middle north of Spain and identification of a novel mutation (1341G→A)

We have analyzed 39 unrelated cystic fibrosis (CF) families by denaturing gradient gel electrophoresis (DGGE) and direct sequencing in order to determine the spectrum of CF mutations in our population. This approach has allowed us to detect 72 out of the 78 CF chromosomes (92.3%). The DF508 mutation was found to be present in 51/78 (65.4%) CF chromosomes, in accordance with the predicted Northwest‐Southeast gradient within the European population. Another 14 known mutations, and the novel 1341G→A mutation were identified. Nine out of fifteen non DF508 mutations were present in a single chromosome. The 1341G→A mutation, found in 2 unrelated patients, is a new mutation associated to severe phenotype, causing pancreatic insufficiency and chronic lung infections. Our data suggest a different distribution of non‐DF508 mutations in our population when compared with previous studies carried out in Spanish CF families. Six out of the 14 non‐F508 in our study were not present in a recent study carried out in 640 Spanish families with CF. These six mutations account for 29.6% non DF508 chromosomes in our sample. Hum Mutat 14:89, 1999. © 1999 Wiley‐Liss, Inc.     

A170P mutation in SHOX gene in a patient not presenting with Madelung deformity

Idiopathic short stature is a multifactorial disease caused by defects in several genes. Among them, short stature homeobox-containing gene (SHOX) mutations have an incidence of 2%-15% within the idiopathic short population. The authors report a patient with moderate intellectual disability, short stature and no other radiological traits referred for subtelomeric screening. MLPA and sequencing results showed a heterozygous mutation in SHOX gene (A170P). This mutation has been described to fully cosegregate with Madelung deformity in patients affected with Léri-Weill dyschondrosteosis and Langer mesomelic dysplasia. The authors report the first case of idiopathic short stature due to the A170P mutation in a patient without any radiological trait. The A170P mutation is the most prevalent mutation in the Spanish gypsy population affected with short stature disorders. The authors strongly recommend SHOX screening for deletions, duplications and point mutations in patients affected with short stature although they do not present any radiological traits.