Class III Malocclusion: Missense Mutations in DUSP6 Gene

Objective: To determine the DUSP6 gene mutation in three generations of Malaysian Malay subjects having Class III malocclusion. Material and Methods: Genetic analyses of DUSP6 gene were carried out in 30 subjects by selecting three individuals representing three generations, respectively, from ten Malaysian Malay families having Class III malocclusion and 30 healthy controls. They were submitted Clinical Evaluation to clinical examination, lateral cephalometric radiographs, dental casts, and/ or facial and intra-oral photographs. Buccal cell was taken from each participant of Class III malocclusion and control groups. DNA extractions from buccal cell were carried out using Gentra puregene buccal cell kit. Bio Edit Sequence Alignment Editor software was used to see the sequencing result. Results: A heterozygous missense mutation c.1094C>T (p. Thr 365 Ile) was identified in DUSP6 gene in three members of one family with Class III malocclusion, whereas no mutation was found in the control group. Conclusion: Current study successfully identified a missense mutation in DUSP6 gene among one Malaysian Malay family affected by Class III malocclusion. The outcome of this study broadened the mutation spectrum of Class III malocclusion and the importance of DUSP6 gene in skeletal functions.

Pedigree study of hereditary small cerebral vascular disease caused by c.821G＞A heterozygous mutation of HtrA serine protease-1 gene / 中华神经科杂志

Objective To investigate the clinical manifestations,imaging features,molecular genetic characteristics and possible pathogenic mechanisms of hereditary cerebral small vessel disease (CSVD) caused by heterozygous mutation of HtrA serine protease-1 (HTRA1) gene.Methods The clinical data of a Chinese Han family with CSVD carrying a heterozygous mutation of HTRA 1 gene,which came from the Department of Neurology,Henan Provincial People's Hospital in March 2018,were analyzed retrospectively.The clinical and radiographic features were summarized.Several high-throughput whole exon high-throughput sequencing was used to capture the mutation sites and the Sanger sequencing was used to validate the results.The family diagram was drawn and the 3D model construction and mutation function prediction were performed using silico tools.The relevant literature was reviewed and the pathogenesis was explored.Results The pedigree map showed that the family had an autosomal dominant inheritance pattern.Three generations of the family were investigated,and three family members in the same generation suffered from the disease.The first symptom of the proband was diplopia at the age of 39,accompanied by recurrent stroke,cognitive impairment and mood disorders,without alopecia.Head magnetic resonance imaging revealed bilateral diffuse,symmetric lesions,multiple lacunar infarcts,perivascular space,and microbleeds.The elder sister of the proband developed symptoms of left limb weakness at the age of 46,whose other clinical and imaging features were similar to those of the proband.The proband's mother died at the age of 59 due to repeated strokes.Whole exon sequencing indicated heterozygous missense mutation at c.821G＞A locus of HTRA1 gene in the proband and her 4th elder sibling,which was a new pathogenic mutation after consulting several mutation sites of databases.Function prediction suggested pathogenicity.Conclusions The heterozygous mutation of c.821G＞A in HTRA1 gene may lead to autosomal dominant CVSD.This genetic type should be given clinical attention.

Hallazgo de una nueva mutación en una familia chilena con diabetes monogénica: caso clínico / Finding of a new mutation in a Chilean family with monogenic diabetes: report of one case

We report a 21 years old woman, without offspring, with diabetes mellitus diagnosed at 17 years of age, without ketosis or weight loss. Her body mass index was 18 kg/m2. Her C peptide was normal (2.3 ng/ml) and diabetes mellitus type 1 autoantibodies were negative. A monogenic diabetes Maturity Onset Diabetes of the Young (MODY) was proposed. Her family study disclosed a diabetic father and a brother with altered fasting glucose levels. The University of Exeter score for MODY yielded a 75.5% probability of MODY2. In the genetic-molecular study of the glucokinase gene (MODY2), the patient had a mutation at position 1343 of exon 10, corresponding to a heterozygous substitution of guanine by adenine (1343 G >A). The same mutation was found in her father and brother. This mutation is different from those previously described in the literature. The described change determines that a glycine is replaced by aspartic at amino acid 448 of the enzyme (non-synonymous substitution). The diagnosis of MODY2 was therefore confirmed in the patient and her father. The mutation was inherited by paternal line.

Analysis of inherited dysfibrinogenemia pedigree associated with a heterozygous and deletion mutantion in the FGG gene / 中华检验医学杂志

Objective To analyze the phenotype and genotype of inherited dysfibrinogenemia pedigree associated with a novel heterozygous and deletion mutation in the FGG gene,and to investigate its molecular mechanism.Methods The clinical data were collected from the proband found at our hospital and her family members in April 2016.The activity plasma fibrinogen(Fg:C), activated partial thromboplastin time(APTT),prothrombin time(PT), thrombin time(TT)were detected by coagulation method and the antigen plasma fibrinogen(Fg:Ag), D-Dimer(D-D), fibrinogen degradation products (FDPs)were analyzed by immunoturbidimetry method.All of the exons and exon-intron boundaries of the genes of FGA, FGB and FGG with the fibrinogen(Fg)were amplified by PCR and followed by direct sequencing.And further verification were performed by cloning sequence and non-denatured polyacrylamide gel electrophoresis and silver staining.The conservatism of mutated gene locus were analyzed by ClustalX-2.1-win.The change of the protein spatial structure and the intermolecular forces with mutation were analyzed by Pymol.Results The Fg:C of the proband was significantly reduced(0.30 g/L)and the Fg:Ag of the proband was normal(2.00 g/L).Their Fg:C were both significantly reduced and the Fg:Ag were both normal(0.42 g/L,2.09 g/L & 0.47 g/L,2.42 g/L, respectively), these were found in her mother and grandma.Genetic analysis revealed a novel heterozygous and deletion mutation with c.944 _c.952 delCCTTTGATG in exon 8 of FGG gene in the proband,predicting a heterozygous 289_291delAla,Phe,Asp mutation.The same mutations were carried by her mother and grandma, but her father and grandpa were normal.Homology analysis indicated that the Ala 289,Phe290 and Asp291 were maintained highly conservative in homogenous species.Protein model analysis found that the original hydrogen bonds were disappeared when the deletion mutation happened with the Ala 289,Phe290 and Asp291.Conclusion The heterozygous and deletion mutation with 289_291delAla,Phe,Asp in the γchain of fibrinogen were identified that could cause the rearrangement of the Fg molecular space structure and the reduction of the structure stability,so the mutation probably underly the dysfibrinogenemia in this pedigree.(Chin J Lab Med,2018, 41:305-311)

Analysis of neurofibromatosis 1 gene mutation in a family with neurofibromatosis and its clinical significance / 中华神经科杂志

To screen the pathogenic mutation location in a genetic family with the neurofibromatosis (NF1) by the next generation sequencing and analyze the clinical phenotype,Illumina Miseq sequencing was applied to capture and analyze the target regions of NF1 family's probands,and furtherly find out the suspicious mutations,as well as to verify the family members by Sanger sequencing.Two rare variants were identified in proband,including the heterozygous missense mutation c.C3649T (p.P1217S) in KIF1B gene and the missense mutation c.T6311C (p.L2104P) on exon 41 of NF1 gene (NM_000267.3).The amino acid at position 2104 was found to be changed from leucine to proline in NF1.The protein prediction SIFT and Polyphen-2 values were 0,0.997,which predicted a conformational change in the encoded protein and eventually affected its function.The mutation c.T6311C in NF1 gene was detected in all patients in this family,which showed genetic co-segregation.The clinical phenotype was neurofibroma in the spinal canal.There were no café au lait spots,iris Lisch nodules,scoliosis,tinnitus,heating loss,or elevated intracranial pressure.The missense mutation c.T6311C (p.L2104P) in NF1 gene might be the genetic cause of this hereditary disease of neurofibromatosis.

Mutation analysis of the FGFR3 gene in a patient with Crouzon syndrome complicated by acanthosis nigricans / 中华皮肤科杂志

A 7-year-old female patient presented with frontal bossing and exophthalmos complicated by skin pigmentation all over the body for 7 years.Pigmentation was seen on the flexor aspects of the bilateral elbows 1 week after birth,and skin pigmentation gradually appeared at multiple body sites 1 year later.She had suffered from lacrimal duct obstruction since childhood,and repeated dredging of the duct was ineffective.Parents of the child were healthy and non-consanguineous marriage,and had no family history of the same disease.Physical examination showed square-shaped skull,frontal bossing,maxillary hypoplasia,mandibular prognathism,exophthalmos,ocular hypertelorism,depressed nasal bridge,dental malocclusion,and irregular dentition.Skin examination showed dark brown skin all over the body,coarse skin on the neck,axillary and inguinal regions,papillomatous cutaneous thickening,with velvet-like appearance.The patient was diagnosed with Crouzon syndrome complicated by acanthosis nigricans (CAN).Polymerase chain reaction (PCR)and DNA sequencing were performed to detect mutations in the FGFR3 gene in the patient with CAN,her parents and 100 unrelated healthy controls.A heterozygous missense mutation (C.1172 C ＞ A) was identified in the FGFR3 gene in the proband,but not in her parents or the 100 unrelated healthy controls.The missense mutation in the FGFR3 gene may be a causative mutation leading to the clinical manifestations of the patient.

Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy / 国际脑血管病杂志

Cerebral small vessel disease is a group of heterogeneous diseases with stroke and cognitive impairment as the main clinical features.It can be divided into sporadic type and hereditary type.Cerebral autosomal recessive arteriopathy with subcortical infarcts and leukoencephalopathy (CARASIL) belongs to hereditary cerebral small vessel disease.It has been reported in China,Japan,Spain,Greece,and other countries.The diagnosis mainly depends on characteristic clinical symptoms,imaging features,and genetic testing.CARASIL manifests as diffuse white matter abnormal signal and subcortical multiple infarcts on MRI,and it caused by HTRA1 gene mutation.

Analysis of GJA3 mutation associated with a Chinese family with autosomal dominant congenital cataract by whole-exome sequencing / 中华实验眼科杂志

Congenital cataract is one of the important reasons for the blindness of children,and most congenital cataracts are genetic.At present,thirty-nine genes have been identified relating to autosomal dominant congenital cataract (ADCC).Objective This study was to identify and analyze the virulence gene of a Chinese family pedigree with ADCC by whole-exome sequencing.Methods A Chinese ADCC family was recruited in Affiliated First Hospital of Zhengzhou University from August to September in 2014.The family disease history and clinical data were recorded.The peripheral venous blood of 10 ml was collected in 14 patients with congenital cataract and 14 families with normal phenotype,and the peripheral blood samples were obtained from 100 healthy examined people as controls.The genomic DNA was extracted form all subjects using standard phenol chlorum method,and proband DNA was screened by whole-exome sequencing.Then mutation locus of the candidate gene was selected after compared with the information of database in the proband.The mutation locus of the candidate gene from 14 normal families and 100 healthy controls were amplified and sequenced by PCR technique based on the primer sequence of mutation locus of proband to verify the pathogenic gene of this ADCC family.This study protocol was approved by Ethic Committee of Affiliated First Hospital of Zhengzhou University and complied with Helsinki Declaration.Written informed consent was obtained from subjects or custodian before any medical examination.Results The family had a total of 5 generations of 68 members,in which 20 subjects were found with congenital cataract.The inheritance mode consisted with autosomal dominant inheritance.Cortical cataract was found in both eyes in the patients.Whole-exome sequencing showed that the 143rd ribonucleotide A of exon 2 explicit factor of chromosome 13 GJA3 gene mutated into G (c.143A＞G) in the proband,which resulted in the 48th amino acids changed from glutamate into glycine (p.E48G).PCR amplification product sequencing displayed that the same mutation of DNA appeared in all the patients of this family,while not the same mutation was seen in the candidate genes of normal phenotype families and 100 healthy controls.Conclusions GJA3 gene c.143A＞G is a virulence mutation site in this ADCC family,it is a supplement of the mutation spectrum of GJA3 gene.

A novel mutation in CACNA1A associated with familial hemiplegic migraine / 中华检验医学杂志

Objective To identify mutations of CACNA1A gene in a family with hemiplegic migraine.Methods Total genomic DNA was extracted from a family with 3 affected members and 1 000 healthy controls.The proband and his patient sister were subjected to exome sequencing.Ten family members including 3 patients were subjected to linkage analysis.The coding exons of the CACNA1A gene were amplified and sequenced in affected and normal individuals. Bioinformatics analysis were performed.Results A novel CACNA1A mutation was identified in the 3 patients.The nonsense mutation of A to G was detected at nucleotide 1168 ( c.1168A >G) which converted the Asn codon ( AAT) to Asp (GAT) in exon 8.Conclusion The mutation(N390D) detected in the present study is considered to result in the Chinese Hemiplegic migraine family.

Phenotype and genotype analysis of in herited dysplasminogenemia caused by plasminogen Ala601Thr mutation / 中华检验医学杂志

Objective To detectthe phenotype and gene mutations underlying aninherited dysplasminogenemia pedigree and search the virulence gene.Methods The peripheral venous blood samples of the proband and his family members (fourteen subjects of three generations in total) were collected,and their prothrombin time(PT),activated partial thromboplastin time(APTF),thrombin time(TT),fibrinogen (FIB),fibrinogen degradation products (FDP),D-dimmer (D-D)weretested on a STAGO analyzer,the plasminogen activity (PLG:A) and plasminogen antigen (PLG:Ag) were analyzedby thechromogenic substrate assay and rocket immunoelectrophoresis,respectively.All 19 exons,5' and 3' untranslated regions of PLGwere amplified with PCR.Direct DNA sequencing was used to analyze the amplified products,which wereconfirmed by backward sequencing.Three bioinformatics online softwares (SIFT,PolyPhen-2 andMutationTaster) were used to forecast the possible impact of the mutations on the protein function.At last,themodel analysis of mutate site was taken on a Swiss-Pdb Viewer software.Results The PLG:Avalue of theproband and other 6 family members were decreased to the half,while the PLG:Ag was normal.The D-Dand FDP value of the proband,his grandma and father were slightly higher.DNA sequencing has revealedthat the proband and the other 6 members of this family had the same mutation of g.38829G ＞ A in exon 15,leading to the missense mutationp.Ala601Thr.The results of bioinformatics softwares showed that themutation could affect the thePLGfunction.Protein model analysis indicated that the hydrophobic interaction force and hydrogen bond between the amino acids were changed,which might affect the stability of the PLG.In addition,all the members of this family take the heterozygous SNP of g.2501C ＞ A in the 5 ＇UTR.Conclusions The p.Ala601Thr found in the inherited dysplasminogenemia pedigree in the exon 15 was responsible for the reduced PLG:A of the family,the dysplasminogenemia and this mutation were both reported for the first time in China.

R607C mutation of NOTCH3 gene and clinical features in 4 CADASIL families in Henan, China / 国际脑血管病杂志

Objective To investigate the NOTCH3 gene mutation and clinical features in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) families.Methods The clinical features of 4 CADASIL probands in Henan,China were analyzed retrospectively,and the incidences of other members in their families were investigated.The NOTCH3 gene mutations in the 3rd,4th,llth,and 18th exons were detected and the results were analyzed in the patients and some family members.Results Gene sequencing showed that 6 patients in 4 families and 1 mutant carrier had NOTCH3 gene R607C mutation in exon llth,they all met the clinical features of CADASIL.Three patients accompanied with vascular risk factors.The clinical stroke patients had unilateral limb weakness.All 5 patients with complete head MRIdata had thalamic infarction.Conclusions In the 4 CADASIL families of R607C mutation,the clinical features of 6 patients with CADASIL were similar,but there were individual differences in different family members.Imaging examination has important role in the diagnosis of CADASIL.The vascular risk factors,such as hyperte.

α-Smooth Muscle Actin and ACTA2 Gene Expressions in Vasculopathies

ABSTRACT α-smooth muscle actin, encoded by ACTA2 gene, is an isoform of the vascular smooth muscle actins, typically expressed in the vascular smooth muscle cells contributing to vascular motility and contraction. ACTA2 gene mutations cause a diversity of diffuse vasculopathies such as thoracic aortic aneurysms and dissections as well as occlusive vascular diseases, including premature coronary artery disease and ischemic stroke. Dynamics of differentiation-specific α-smooth muscle actin in arterial smooth muscle cells and proliferation of the proteins have been well described. Although a variety of research works have been undertaken in terms of modifications of α-smooth muscle actin and mutations of ACTA2 gene and myosin, the underlying mechanisms towards the pathological processes by way of gene mutations are yet to be clarified. The purpose of the present article is to describe the phenotypes of α-smooth muscle actin and implications of ACTA2 mutations in vasculopathies in order to enhance the understanding of potential mechanisms of aortic and coronary disorders.

Mutation analysis of the OSMR gene in a family with familial primary cutaneous amyloidosis / 中华皮肤科杂志

Objective To identify mutations in the OSMR gene in a pedigree with familial primary cutaneous amyloidosis (FPCA).Methods Clinical data were collected from a pedigree with FPCA.Peripheral blood samples were obtained from the proband,his 19 relatives,and 50 unrelated healthy human controls.Genomic DNA was extracted from these blood samples,and subjected to PCR for the amplification of 18 encoding exons and their flanking sequences of the OSMR gene followed by DNA sequencing.Results A heterozygous missense mutation c.2081C ＞ T,which leads to the substitution of proline by threonine at position 694,was detected in the OSMR gene of the proband and his affected relatives,but not in unaffected relatives or healthy controls.Conclusion The heterozygous mutation p.P694L in the OSMR gene may cause the clinical phenotype of FPCA in this family.

A Case of Korean Patient with Macular Corneal Dystrophy Associated with Novel Mutation in the CHST6 Gene

To report a novel mutation within the CHST6 gene, as well as describe light and electron microscopic features of a case of macular corneal dystrophy. A 59-year old woman with macular corneal dystrophy in both eyes who had decreased visual acuity underwent penetrating keratoplasty. Further studies including light and electron microscopy, as well as DNA analysis were performed. Light microscopy of the cornea revealed glycosaminoglycan deposits in the keratocytes and endothelial cells, as well as extracellularly within the stroma. All samples stained positively with alcian blue, colloidal iron, and periodic acid-Schiff. Electron microscopy showed keratocytes distended by membrane-bound intracytoplasmic vacuoles containing electron-dense fibrillogranular material. These vacuoles were present in the endothelial cells and between stromal lamellae. Some of the vacuoles contained dense osmophilic whorls. A novel homozygous mutation (c.613 C>T [p.Arg205Trp]) was identified within the whole coding region of CHST6. A novel CHST6 mutation was detected in a Korean macular corneal dystrophy patient.

Mutación en el gen EDA1, Ala349Thr en paciente con displasia ectodérmica hipohidrótica ligada a X / Mutation in the ED1, Ala349Thr in a patient with X-linked hypohidrotic ectodermal dysplasia

Hypohidrotic ectodermal dysplasia (HED) is a very rare disease characterized by the absence of eccrine glands, dry skin, scanty hair, and dental abnormalities. It is caused by mutations within the ED1 gene, which encodes a protein, ectodysplasin-A (EDA). Clinical characteristic are frontal bossing, saddle nose, pointed chin, a prominent supraorbital ridge with periorbital hyperpigmenta-tion, and anodontia. Those affected show great intolerance to heat. We report the first Mexican 2-year-old boy with an Ala349Thr missense mutation from Tamaulipas, México.

Lipodistrofia parcial familiar do tipo Dunnigan: atenção ao diagnóstico precoce / Dunnigan-type familial partial lipodystrophy: attention to precocious diagnosis

A lipodistrofia parcial familiar tipo Dunnigan é uma doença autossômica dominante rara. Em sua forma clássica, é resultante de uma mutação missense heterozigótica no gene LMNA, que codifica a proteína nuclear denominada lâmina tipo A/C. Caracteriza-se pelo desaparecimento progressivo do tecido adiposo subcutâneo nos membros, região glútea, abdome e tronco, que se inicia na puberdade, acompanhado de acúmulo de gordura em outras áreas, como a face, queixo, grandes lábios e região intra-abdominal, conferindo o aspecto de hipertrofia muscular e simulando o fenótipo de síndrome de Cushing. Mulheres afetadas são particularmente predispostas à resistência à insulina e suas complicações, incluindo sinais da síndrome dos ovários policísticos. Com o objetivo de alertar para o diagnóstico precoce, que possibilita a adoção de medidas que minimizam os graves distúrbios metabólicos vinculados à desordem, relatamos o caso de uma paciente em que a investigação foi realizada somente ao final da quinta década de vida. A aparente hipertrofia muscular e o acentuado depósito de gordura nos grandes lábios possibilitam aos médicos ginecologistas a suspeita diagnóstica.

Dunnigan-type familial partial lipodystrophy (FPLD) is an autosomal dominant disease that results from heterozygous missense mutations in LMNA, the gene that encodes nuclear lamin A/C. FPLD is characterized by a progressive disappearance of subcutaneous adipose tissue in the limbs, gluteal region, abdomen and trunk, beginning at the time of or after puberty, and excessive amount of fat in the face, chin, labia majora, and intra-abdominal region, leading to a Cushingoid appearance and increased muscularity phenotype. Affected women are particularly predisposed to insulin resistance and its complications, including features of polycystic ovary syndrome. To emphasize the importance of an early FPLD diagnosis, which is necessary to prevent serious metabolic disturbances, we report a woman diagnosed at about 50 years of age. Increased muscularity and significant labia majora fat deposit made the diagnosis possible by gynecologists.

Análise da expressão dos genes PROP1 e CTNNB1 em craniofaringiomas adamantinomatosos com e sem mutação somática no CTNNB1 / Analysis of PROP1 and CTNNB1 expression genes in adamantinomatous craniopharyngiomas with and without CTNNB1 somatic mutation

Os craniofaringiomas são os tumores mais frequentes da região hipotálamohipofisária na faixa etária pediátrica. Apesar de serem histologicamente benignos, sua tendência infiltrativa e seu comportamento agressivo resultam em significante morbimortalidade. Histologicamente podem ser divididos em dois subtipos: adamantinomatosos e papilíferos. A patogênese dos craniofaringiomas é pouco compreendida. Mutações no gene CTNNB1, que codifica a proteína beta-catenina, são a única alteração molecular conhecida até o momento implicada na tumorigênese dos craniofaringiomas adamantinomatosos. Tais mutações afetam o sítio de degradação da beta-catenina, que passa a se acumular no citoplasma e no núcleo, ativando excessivamente a via de sinalização WNT, através da ligação aos fatores de transcrição da família LEF/TCF, levando a tumorigênese. Recentemente foi descoberto um novo mecanismo de determinação da linhagem celular hipofisária regulado pela beta-catenina, através do qual ela interage diretamente com o PROP1 para determinar a diferenciação celular hipofisária. De acordo com esse modelo, o complexo protéico PROP1/beta- catenina atua simultaneamente como repressor do HESX1 e ativador do PIT1, dependendo dos co-fatores associados. Pacientes com mutações germinativas inativadoras no PROP1 desenvolvem hipopituitarismo e podem apresentar aumento hipofisário com imagens de ressonância nuclear magnética (RNM) da região selar muitas vezes semelhantes àquelas dos craniofaringiomas, com hiperssinal em T1. Por outro lado, camundongos com expressão persistente do Prop1 exibem defeitos na regulação da proliferação celular hipofisária, incluindo cistos da bolsa de Rathke, hiperplasia adenomatosa e tumores, sugerindo que mutações com ganho de função no PROP1 também poderiam contribuir para a patogênese de tumores hipofisários em seres humanos. A semelhança entre as imagens de RNM dos pacientes com craniofaringiomas e daqueles com aumento hipofisário devido a mutações...

Craniopharyngiomas are the the commonest tumors to involve the hypothalamo-pituitary regions in childhood population. Histologically they are benign, and can be divided in two primary subtypes: the adamantinomatous and the papillary. Although histologically benign, their infiltrative tendency and aggressive behavior can result in great morbidity. The pathogenesis of craniopharyngiomas is poorly understood. To date, beta-catenin gene (CTNNB1) mutations have been identified only in the adamantinomatous subtype. These mutations affect the degradation target box of beta-catenin that accumulates in the cytoplasm and the nucleus increasing the transcriptional activity of WNT pathway through interaction with the transcription factors of LEF/TCF family, leading to tumorigenesis. Recently, an interaction between beta-catenin and PROP1 was described as a new mecanism for beta-catenindependent regulation of pituitary cell-lineage determination. According to this novel model, the PROP1/beta-catenin proteic complex would act as a binary switch to simultaneously repress the transcription factor HESX1 and to activate expression of transcription factor PIT1, depending on the associated cofactors. Patients with loss-of-function mutations in PROP1 present combined pituitary hormonal deficiency generally associated with pituitary enlargement and the magnetic resonance imaging (MRI) of the sellar region in these patients sometimes resembles that of the craniopharyngiomas, with T1 hyperintense signal. On the other hand, transgenic mice with persistent Prop1 expression exhibit defects consistent with misregulation of pituitary cell proliferation, including adenomatous hyperplasia with formation of Rathke's cleft cysts and tumors suggesting that misregulation of PROP1 expression in human could contribute to pathogenesis of pituitary tumors. The similarity between the MRI images of craniopharyngiomas patients and that of patients with loss-of-function mutations in...

A MELAS syndrome family harboring two mutations in mitochondrial genome

Mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS) syndrome is a genetically heterogeneous mitochondrial disorder with variable clinical symptoms. Here, from the sequencing of the entire mitochondrial genome, we report a Korean MELAS family harboring two homoplasmic missense mutations, which were reported 9957T>C (Phe251Leu) transition mutation in the cytochrome c oxidase subunit 3 (COX3) gene and a novel 13849A>C (Asn505His) transversion mutation in the NADH dehydrogenase subunit 5 (ND5) gene. Neither of these mutations was found in 205 normal controls. Both mutations were identified from the proband and his mother, but not his father. The patients showed cataract symptom in addition to MELAS phenotype. We believe that the 9957T>C mutation is pathogenic, however, the 13849A>C mutation is of unclear significance. It is likely that the 13849A>C mutation might function as the secondary mutation which increase the expressivity of overlapping phenotypes of MELAS and cataract. This study also demonstrates the importance of full sequencing of mtDNA for the molecular genetic understanding of mitochondrial disorders.

Genetic and expression analysis of the KCNRG gene in hepatocellular carcinomas

The potassium channels are ubiquitous multisubunit membrane proteins, and potassium-dependent alterations in the membrane potential play an important role in the proliferation of many types of cells. This study analyzed the mutation, allelic loss and expression patterns of the KCNRG gene in 77 HCCs in order to determine if the KCNRG gene, which encodes the potassium channel regulating protein, is involved in the tumorigenesis of hepatocellular carcinoma (HCC). One KCNRG missense mutation, CGT->CAT (Arg->His) was found at codon 92 within the T1 domain. Hep3B hepatoma cells were transfected with the wild- or mutant-KCNRG to determine the effect of this mutation in KCNRG. Interestingly, the suppressive cell growth activity of the mutant-type KCNRG was significantly lower than that of the wild-type KCNRG. In addition, allelic loss was detected in 17 out of 64 (26.5%) informative HCC cases, and all were hepatitis B virus (HBV)-positive. Moreover, the allelic loss was closely related to an intrahepatic metastasis (P=0.0247), higher grade (P=0.0078) and clinical stage (P=0.0071). Expression analysis revealed 22 tumor tissues to have a loss of expression of the KCNRG transcript. These results suggest that genetic alterations and the expression of KCNRG might play an important role in the development and/or progression of a subset of HCCs.

Molecular Analysis of Isoleucyl-tRNA Synthetase Mutations in Clinical Isolates of Methicillin-Resistant Staphylococcus aureus with Low-Level Mupirocin Resistance

Emergence and spread of low-level mupirocin resistance in staphylococci have been increasingly reported in recent years. The aim of this study was to characterize missense mutations within the chromosomal isoleucyl-tRNA synthetase gene (ileS) among clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) with low-level mupirocin resistance. A total of 20 isolates of MRSA with low-level mupirocin resistance (minimal inhibitory concentration, 16-64 microgram/mL) were collected from 79 patients in intensive care units for six months. The isolates were analyzed for isoleucyl-tRNA synthetase (IleS) mutations that might affect the binding of mupirocin to the three-dimensional structure of the S. aureus IleS enzyme. All isolates with low-level mupirocin resistance contained the known V588F mutation affecting the Rossman fold, and some of them additionally had previously unidentified mutations such as P187F, K226T, F227L, Q612H, or V767D. Interestingly, Q612H was a novel mutation that was involved in stabilizing the conformation of the catalytic loop containing the KMSKS motif. In conclusion, this study confirms that molecular heterogeneity in ileS gene is common among clinical MRSA isolates with low-level mupirocin resistance, and further study on clinical mutants is needed to understand the structural basis of low-level mupirocin resistance.