Research progress in the relationship between loss of heterozygosity events and antifungal drug resistance in Candida albicans / 中华微生物学和免疫学杂志

Candida albicans as a pathogen of great clinical significance can widely colonize in many ecological niches of human body, especially in the immunocompromised population. Currently, antifungal drugs that can be used in clinical treatment are very limited. However, the genome of Candida albicans has a high rate of mutation, which can help it quickly develop resistance to antifungal drugs. Therefore, drug resistance in Candida albicans remains a great threat to clinical practice. This article focused on the frequent loss of heterozygosity (LOH) events in Candida albicans, summarized the association between LOH and other genomic variants and discussed the relationship of the frequency of de novo mutations, heterozygous status of key drug resistance genes and reproductive pattern with antifungal drug resistance.

Congenital Hyperinsulinemia of Infancy: Role of Molecular Testing in Management and Genetic Counseling

Congenital hyperinsulinemia (CHI) is a genetically and clinically heterogenous disorder. In addition to the standard care of management of the proband, genetic counseling regarding the risk of recurrence in the future siblings is an important part in the management of the disorder. The counseling needs identifcation of accurate etiology and is challenging due to the complexity of the molecular mechanisms of CHI. This case highlights the importance of molecular testing which not only helped in planning the management of the proband with CHI but also helped in providing genetic counseling for which the family had consulted the medical genetics department.

Diagnóstico molecular de pérdida de heterocigosidad para 1p/19q en tumores oligodendrogliales por PCR multiplex en el Instituto Nacional de Enfermedades Neoplásicas, Lima- Perú / Molecular diagnosis of heterozygosity loss for 1p/19q in oligodendroglial tumors by multiplex PCR at the National Institute of Neoplastic Diseases, Lima-Peru

La pérdida de heterocigosidad 1p/19q tiene valor pronóstico clínico y está fuertemente asociada con características histológicas clásicas de oligodendroglioma. Objetivos: El presente artículo, propone un método molecular para determinar la pérdida de heterocigosidad (LOH por sus siglas en inglés) para 1p/19q y permitir la clasificación de tumores oligodendrogliales. Material y Métodos: Se utilizaron muestras en fresco del Banco de Tejidos Tumorales del Instituto Nacional de Enfermedades Neioplásicas (INEN) y biopsias de tejido embebido en parafina de tumores oligodendrogliales, con diagnóstico patológico de oligodendroglioma y oligoastrocitoma. Los métodos propuestos son PCR Multiplex y amplificación de fragmentos por electroforesis capilar de los productos de PCR, y fueron aplicados a un total de 39 casos que presentaban grado histológico II y III. Resultados: Los resultados obtenidos permiten una adecuada clasificación molecular de los tumores oligodendrogliales.

A heterozygosity loss of 1p/19q has clinical prognostic value and is strongly associated with classical histologic features of oligodendroglioma. Objectives: The present article proposes a molecular method to determine the loss of heterozygosity (LOH) for 1p/19q and to allow the classification of oligodendroglial tumors. Material and Methods: Fresh samples from the National Institute of Neoplastic Diseases’ Tumor BioBank and paraffin-embedded tissue biopsies of oligodendroglial tumors with pathological diagnosis of oligodendroglioma and oligoastrocytoma were used. The proposed methods are Multiplex PCR and amplification of fragments by capillary electrophoresis of PCR products, and were applied to a total of 39 cases which presented histological grade II and III. Results: The results obtained allow an adequate molecular classification of oligodendroglial tumors.

Prenatal diagnosis of Wolf-Hirschhorn syndrome: a case report / 中华围产医学杂志

This study reported a case of fetal developmental retardation indicated by ultrasound from 17+2 to 34+5 gestations.Single nucleotide polymorphism (SNP) array was performed to detect the copy number variation in the whole genome for the fetus and parents.A 2.42 Mb deletion at 4p16.3 was found in the fetus,but in neither parents,which suggesting a de novo mutation.Thus,the fetus was finally diagnosed with Wolf-Hirschhorn syndrome.No obvious'Greek warrior helmet'appearance or other facial deformity was observed in the delivered fetus.

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)

Microarray-Based Genomic Analysis Identifies Germline and Somatic Copy Number Variants and Loss of Heterozygosity in Acute Myeloid Leukaemia

@#Introduction: Insights into molecular karyotyping using comparative genomic hybridization (CGH) and single nucleotide polymorphism (SNP) arrays enable the identification of copy number variations (CNVs) at a higher resolution and facilitate the detection of copy neutral loss of heterozygosity (CN-LOH) otherwise undetectable by conventional cytogenetics. The applicability of a customised CGH+SNP 180K DNA microarray in the diagnostic evaluation of Acute Myeloid Leukaemia (AML) in comparison with conventional karyotyping was assessed in this study. Methods: Paired tumour and germline post induction (remission sample obtained from the same patient after induction) DNA were used to delineate germline variants in 41 AML samples and compared with the karyotype findings. Results: After comparing the tumour versus germline DNA, a total of 55 imbalances (n 5-10 MB = 21, n 10-20 MB = 8 and n >20 MB = 26) were identified. Gains were most common in chromosome 4 (26.7%) whereas losses were most frequent in chromosome 7 (28.6%) and X (25.0%). CN-LOH was mostly seen in chromosome 4 (75.0%). Comparison between array CGH+SNP and karyotyping revealed 20 cases were in excellent agreement and 13 cases did not concord whereas in 15 cases finding could not be confirmed as no karyotypes available. Conclusion: The use of a combined array CGH+SNP in this study enabled the detection of somatic and germline CNVs and CN-LOHs in AML. Array CGH+SNP accurately determined chromosomal breakpoints compared to conventional cytogenetics in relation to presence of CNVs and CN-LOHs.

An appraisal of pancreatic cyst fluid molecular markers

Pancreatic malignancy is the third leading cause of cancer related death in the United States with limited viable screening options. By the end of this decade, cancers are poised to become the leading cause of death with pancreatic cancer projected to be the second leading cause of cancer related mortality. Pancreatic cystic lesions (PCLs) are found in approximately 5%–14% of patients due to the increased utilization of cross-sectional imaging, with approximately 8%–10% of pancreatic cancers originating as PCLs. Current screening guidelines have shown discrepancies between morphologic characteristics of PCLs and identifying advanced pancreatic disease. Molecular analysis has emerged as a novel technology to aid in adequate diagnosis and management decisions of PCLs. Mucinous cysts including intraductal papillary mucinous neoplasms (IPMNs) or mucinous cystic neoplasms have similar oncogenic mutations including KRAS, TP53, SMAD4, PIK3CA, PTEN, or CKDN2A, while GNAS and RNF43 mutations are specific only to IPMNs. Serous cystadenomas have been associated with a loss of tumor suppressor gene VHL, while solid-psuedopapillary neoplasms have an oncogenic mutation CTNNB1. A specific molecular marker to diagnose existing high-grade dysplasia or impending malignant transformation is yet to be identified. Moving forward it is important to advance technology in isolating and identifying high-risk molecular markers from cyst fluid while considering their increased utilization in the evaluation of PCLs.

Molecular biology techniques for loss of heterozygosity detection: the glioma example / Técnicas de biologia molecular para avaliação da perda de heterozigosidade: o exemplo em glioma

ABSTRACT In recent years, many oncology institutions have implemented the use of molecular approaches to assess and manage cancer patients. One commonly observed type of genetic alteration in cancer is the loss of heterozygosity (LOH). In the clinical setting, this molecular genetic marker is an important tool for disease prognosis, diagnosis and treatment. For example, the loss of 1p/19q is a classical molecular marker for oligodendroglioma assessment. In addition, this marker is associated with a favorable prognosis and chemosensitivity in oligodendroglial tumors. Interpretation of the clinical significance of molecular markers requires that health professionals and biomedical scientists understand the basic theoretical fundamentals of molecular diagnostic techniques. Although there are different methodologies to assess LOH, including high-performance techniques, this review aims to describe the polymerase chain reaction (PCR)-based LOH assays and fluorescence in situ hybridization (FISH), which are the molecular techniques most used for evaluation of 1p/19q status in pathology laboratories.

RESUMO Nos últimos anos, instituições de oncologia têm implementado o uso de abordagens moleculares para avaliar e conduzir pacientes com câncer. O tipo mais comum de alteração encontrada no câncer é a perda de heterozigosidade (LOH). Na clínica, esse marcador molecular pode ter importância para o prognóstico, o diagnóstico e/ou na decisão do tratamento. Por exemplo, a perda de 1p/19q é um marcador molecular clássico para a avaliação do oligodendroglioma. Além disso, esse marcador está associado ao prognóstico favorável e à quimiossensibilidade em tumores oligodendrogliais. A interpretação do significado clínico dos marcadores moleculares exige que os profissionais da área da saúde entendam os fundamentos básicos teóricos das técnicas de diagnóstico molecular. Embora existam diferentes metodologias para avaliar a LOH, inclusive técnicas de alta performance, esta revisão tem o objetivo de descrever o ensaio de LOH com base na reação da cadeia da polimerase (PCR) e a hibridização in situ fluorescente (FISH), que são as técnicas moleculares mais usadas para avaliação do status 1p/19q em laboratórios de patologia.

Identifying the similarities and differences between single nucleotide polymorphism array (SNPa) analysis and karyotyping in acute myeloid leukemia and myelodysplastic syndromes

Objective: To standardize the single nucleotide polymorphism array (SNPa) method in acute myeloid leukemia/myelodysplastic syndromes, and to identify the similarities and differ- ences between the results of this method and karyotyping. Methods: Twenty-two patients diagnosed with acute myeloid leukemia and three with myelodysplastic syndromes were studied. The G-banding karyotyping and single nucleotide polymorphism array analysis (CytoScan(r) HD) were performed using cells from bone marrow, DNA extracted from mononuclear cells from bone marrow and buccal cells (BC). Results: The mean age of the patients studied was 54 years old, and the median age was 55 years (range: 28-93). Twelve (48%) were male and 13 (52%) female. Ten patients showed abnormal karyotypes (40.0%), 11 normal (44.0%) and four had no mitosis (16.0%). Regarding the results of bone marrow single nucleotide polymorphism array analysis: 17 were abnor- mal (68.0%) and eight were normal (32.0%). Comparing the two methods, karyotyping identified a total of 17 alterations (8 deletions/losses, 7 trissomies/gains, and 2 translocations) and single nucleotide polymorphism array analysis identified a total of 42 alterations (17 losses, 16 gains and 9 copy-neutral loss of heterozygosity). Conclusion: It is possible to standardize single nucleotide polymorphism array analysis in acute myeloid leukemia/myelodysplastic syndromes and compare the results with the abnormalities detected by karyotyping. Single nucleotide polymorphism array analysis increased the detection rate of abnormalities compared to karyotyping and also identified a new set of abnormalities that deserve further investigation in future studies. .

The clonal origin of diffuse hepatocellular carcinoma / 天津医药

Objective To determine the tumor clonal origin of diffuse hepatocellular carcinoma (D-HCC) and clinical outcome after liver transplantation. Methods Fourteen D-HCC patients who underwent liver transplantation in the Tianjin First Central Hospital between August 2004 to November 2012 were evaluated retrospectively. Their clinical characteristics and data of disease-free survival postoperatively were gathered. Twelve loss of heterozygosity sites (LOH) on high frequency microsatellite were selected. The tumor clonal origin of D-HCC was assessed by the means of PCR-SSCP. Results Of 14 D-HCC patients, intrahepatic metastasis (IM) occurred in 11 cases (11/14), and IM with multicentric occurrence (MO) occurred in 3 cases (3/14). The disease-free survival time was 4.5 to 37.4 months, and the median time was 8.7 months. Conclusion The most frequent tumor clonal origin of D-HCC was IM. Liver transplantation may be the effective treatment for D-HCC.

Reprogramme-induced genomic stability / 中国组织工程研究

BACKGROUND:Some studies have shown that more copy number variations are present in early passage human induced pluripotent stem cells than later passage human human induced pluripotent stem cells, their parental somatic fibroblasts or human embryonic stem cells. OBJECTIVE:To investigate whether the reprogramming process itself compromises genomic stability and further explore the efficiency of induced pluripotent stem cellestablishment. METHODS:Using high-resolution Affymetrix CytoScan HD array, we compared copy number variations and loss of heterozygosity in early passage induced pluripotent stem cells with their fibroblast cellorigins from genetic epilepsy patients. RESULTS AND CONCLUSION:Compared with somatic fibroblasts from genetic epilepsy patient, there was no difference in the loss of heterozygosity between the two types of cells, but more copy number variations were present in early passage human induced pluripotent stem cells which were characterized as microduplication and involved oncogenic genes. Results demonstrate the dynamic nature of genomic abnormalities during reprogramming process and the necessity of frequent monitoring human induced pluripotent stem cells to assure their genomic stability and clinical safety.

Loss of Heterozygosities in Five Tumor Suppressor Genes (FHIT Gene, p16, pRb, E-Cadherin and p53) in Thyroid Tumors

OBJECTIVES: To evaluate the loss of heterozygosities (LOH) of chromosomes 3p14 (FHIT gene), 9p21 (p16), 13q21 (pRb), 6q22 (E-cadherin) and 17p13 (p53) in various thyroid tumors. METHODS: Eighty thyroid tumor cases (20 follicular adenomas, 10 follicular carcinomas, and 50 papillary carcinomas) have been analyzed for the presence of LOH in chromosomes 3p14, 9p21, 13q21, 6q22, and 17p13 allelic loss, using microsatellite markers and DNA obtained from formalin-fixed paraffin-embedded archival tissues. RESULTS: LOH on 3p14 was found in 10.5%, 33.3%, and 30.4% of follicular adenomas, follicular carcinomas, and papillary carcinomas, respectively. LOH on 9p21 was detected in 6%, 44.4%, and 47.8%, respectively. LOH on pRb gene was found in 5.3%, 20.0%, and 35.4%, respectively. LOH on E-cadherin gene was found in 5.3%, 22.2%, and 43.8%, respectively. LOH on 17p13 was detected in 0%, 40%, and 45.8%, respectively. LOH in FHIT gene, p16, pRb, E-cadherin, and p53 genes were more frequently identified in follicular carcinoma and papillary carcinoma than in follicular adenoma. CONCLUSION: LOH results of the five tumor suppressor genes (FHIT gene, p16, pRb, E-cadherin, and p53) showed statistical differences between benign tumor and malignant tumor. Among papillary carcinoma, LOH in p16, E-cadherin and p53 genes well correlated with poorly differentiated grade, and LOH of E-cadherin was associated with lymph node metastasis.

Clinical Significance of Previously Cryptic Copy Number Alterations and Loss of Heterozygosity in Pediatric Acute Myeloid Leukemia and Myelodysplastic Syndrome Determined Using Combined Array Comparative Genomic Hybridization plus Single-Nucleotide Polymo

The combined array comparative genomic hybridization plus single-nucleotide polymorphism microarray (CGH+SNP microarray) platform can simultaneously detect copy number alterations (CNA) and copy-neutral loss of heterozygosity (LOH). Eighteen children with acute myeloid leukemia (AML) (n=15) or myelodysplastic syndrome (MDS) (n=3) were studied using CGH+SNP microarray to evaluate the clinical significance of submicroscopic chromosomal aberrations. CGH+SNP microarray revealed CNAs at 14 regions in 9 patients, while metaphase cytogenetic (MC) analysis detected CNAs in 11 regions in 8 patients. Using CGH+SNP microarray, LOHs>10 Mb involving terminal regions or the whole chromosome were detected in 3 of 18 patients (17%). CGH+SNP microarray revealed cryptic LOHs with or without CNAs in 3 of 5 patients with normal karyotypes. CGH+SNP microarray detected additional cryptic CNAs (n=2) and LOHs (n=5) in 6 of 13 patients with abnormal MC. In total, 9 patients demonstrated additional aberrations, including CNAs (n=3) and/or LOHs (n=8). Three of 15 patients with AML and terminal LOH>10 Mb demonstrated a significantly inferior relapse-free survival rate (P=0.041). This study demonstrates that CGH+SNP microarray can simultaneously detect previously cryptic CNAs and LOH, which may demonstrate prognostic implications.

Cutaneous mosaicisms: concepts, patterns and classifications / Mosaicismos cutaneos: conceitos, padroes e classificacoes

A mosaic is an organism composed of two or more genetically distinct cell populations derived from a genetically homogeneous zygote. Cutaneous mosaicisms are the clinical expressions of these disorders. The main event which allows the existence of mosaicism is a genetic mutation, either structural or functional. Cutaneous mosaicisms usually manifest by specific patterns on the skin and the archetypic pattern is the system of Blaschko lines, but others include checkerboard, phylloid, large patches without midline separation and lateralization. Since 1901, when Blaschko lines were first described, the study of mosasicism has helped to elucidate the behavior of numerous genetic diseases, generating therapeutic perspectives for these pathologies, including the promising gene therapy.

Um mosaico é um organismo formado por duas ou mais populações de células geneticamente distintas originadas a partir de um mesmo zigoto geneticamente homogêneo. Os mosaicismos são as expressões clínicas dessa desordem, e a mutação gênica seu evento determinante, que pode ser tanto estrutural quanto funcional. Os mosaicismos cutâneos costumam se expressar em padrões específicos, dentre os quais podem ser mencionados as prevalentes linhas de Blaschko, o padrão "checkerboard", o padrão filóide, o padrão em placa sem separação na linha média e o padrão de lateralização, que serão abordados neste artigo. Desde 1901, momento da primeira descrição das linhas de Blaschko, o estudo dos mosaicismos tem contribuído para a elucidação do comportamento de numerosas desordens genéticas, de forma a criar perspectivas terapêuticas para essas doenças, incluindo a promissora terapia gênica.

SNP array technology: an array of hope in breast cancer research

Breast cancer is the most common malignancy in women worldwide. The incidence of breast cancer in Malaysia is lower compared to international statistics, with peak occurrence in the age group between 50 to 59 years of age and mortality rates of 18.6%. Despite current diagnostic and prognostic methods, the outcome for individual subjects remain poor. This is in part due to breast cancers’ wide genetic heterogeneity. Various platforms for genetics studies are now employed to determine the identity of these genetic abnormalities, including microarray methods like highdensity single-nucleotide-polymorphism (SNP) oligonucleotide arrays which combine the power of chromosomal comparative genomic hybridization (cCGH) and loss of heterozygosity (LOH) in the offering of higher-resolution mappings. These platforms and their applications in highlighting the genomic alteration frameworks manifested in breast carcinoma will be discussed.

Adjuvant chemotherapy of stage Ⅱ colon cancer / 国际肿瘤学杂志

For stage Ⅱ colon cancer patients after surgery,the benefit of adjuvant chemotherapy remains controversial.Several studies indicate that the patients with high-risk stage Ⅱ colon cancer can benefit from adjuvant chemotherapy after surgery.According to the clinical and pathological features,the stage Ⅱcolon cancer patients including T4 lesion,perforation,peritumoral lymphovascular invasion can benefit from the adjuvant chemotherapy of oxaliplatin.In the horizontal of molecular and genetic levels,the stage Ⅱ colon cancer patients can express high microsatellite instability (MSI-H) and cannot benefit from the chemotherapy of Fluorouracil.The guiding functions of 18q loss of heterozygosity (18q LOH),Cx43 and gene expression profiling in adjuvant chemotherapy are still unclear,and need further study.

Primary study of loss of heterozygosity on chromosome 1p36 in invasive ductal breast carcinoma / 肿瘤研究与临床

Objective The study of loss of heterozygosity (LOH) on chromosome 1p36 was performed to locate the deletion areas probably harboring tumor suppressor genes in invasive ductal breast carcinoma not otherwise specified (IDC NOS).Methods Eighty paired breast cancer/normal tissue DNA samples were examined for LOH on chromosome lp36 using eight polymorphic microsatellite (MS) loci.The PCR products were electrophoresed on 8％ denatured polyacrylamide gel and stained using silver staining.Finally,the data were analysed and compared with the clinicopathological parameters using statistical analysis.Results In 80 IDC NOS,LOH was identified in 45 cases (56.3 ％) at least in one MS locus.MS locus D1S1310 showed the highest rate of LOH [35.7％ (25/70)].Conclusion Chromosome 1p36 might be the highly deleted region.The results of this study indicate that the chromosomal regions 1p36.23-33 might contain tumor suppressor genes associated with human breast carcinomas.

Research progress of gene changes in gastric cancer / 肿瘤研究与临床

Gastric cancer is one of the leading causes of cancer mortality in the world.The development and progression of gastric cancer is attributed to a number of genetic and epigenetic alterations of oncogene and tumor suppress gene.

Pérdida de heterocigocidad e identificación de portadoras de distrofia muscular de Duchenne: un caso familiar con evento de recombinación / Loss of heterozygosity and carrier identification in Duchenne muscular dystrophy: a familiar case with recombination event / Perda de heterozigosidade e identificação de portadoras de distrofia muscular de Duchenne: um caso familiar com evento de recombinação

La distrofia muscular de Duchenne y Becker (DMD/DMB) es una entidad de herencia recesiva ligada al cromosoma X que se presenta con debilidad muscular y es causada por mutaciones en el gen de la distrofina. La pérdida de heterocigocidad permite identificar a las mujeres portadoras de deleción en el gen de la distrofina mediante haplotipos. Objetivo: identificar mujeres portadoras en una familia con un paciente afectado por DMD mediante análisis de pérdida de heterocigocidad. Materiales y métodos: se analizaron nueve miembros de una familia con un afectado de DMD. Se hizo extracción de ADN y amplificación de diez STR del gen de la distrofina; se construyeron haplotipos, y se determinó el estado de portadora de deleción en dos de las seis mujeres analizadas, quienes mostraron pérdida de heterocigocidad de tres STR. Se establecieron algunos eventos de recombinación. Resultados: dos de las seis mujeres analizadas, mostraron pérdida de heterocigocidad en tres de los diez STR genotipificados, indicando su estado de portadora de deleción en este fragmento del gen de la distrofina. Con la segregación familiar de los haplotipos se establecieron eventos de recombinación. Conclusiones: mediante pérdida de heterocigocidad es posible establecer el estado de portadora de deleción en el gen de la distrofina con un 100% de certeza. La construcción de haplotipos identifica el cromosoma X portador de la deleción en familiares del caso índice. Se evidenció un evento de recombinación en una de las hermanas del afectado, lo que hace indeterminado su estado de portadora.

Duchenne/Becker Muscular Dystrophy (DMD/BMD) is an X-linked recessive disease characterized by muscular weakness. It is caused by mutations on the dystrophin gen. Loss of heterozygosity allows us to identify female carriers of deletions on the dystrophin gen. Objective: identify female carriers in a family with a patient affected by DMD. Material and methods: nine family members and the affected child were analyzed using DNA extraction and posterior amplification of ten STRs on the dystrophin gen. Haplotypes were constructed and the carrier status determined in two of the six women analyzed due to loss of heterozygosity in three STRs. Additionally, we observed a recombination event. Conclusions: loss of heterozygosity allows us to establish with a certainty of 100% the carrier status of females with deletions on the dystrophin gen. By the construction of haplotypes we were able to identify the X chromosome with the deletion in two of the six women analyzed. We also determined a recombination event in one of the sisters of the affected child. These are described with a high frequency (12%). A possible origin for the mutation is a gonadal mosaicism in the maternal grandfather or in the mother of the affected child in a very early stage in embryogensis. This can be concluded using the analysis of haplotypes.

A distrofia muscular de Duchenne e Becker (DMD/DMB) é uma entidade de herança recessiva ligada ao cromossoma X que se apresenta com debilidade muscular e é causada por mutações no gene da distrofia. A perda de heterozigosidade permite identificar às mulheres portadoras de deleção no gene da distrofina mediante haplótipos. Objetivo: identificar mulheres portadoras em uma família com um paciente afetado de DMD mediante análises de perda de heterozigosidade. Materiais e métodos: se analisaram nove membros de uma família com um afetado de DMD. De fez extração de ADN e amplificação de dez STR do gene da distrofina; construíram-se haplótipos, e determinou-se o estado de portadora de deleção em duas das seis mulheres analisadas, as quais mostraram perda de heterozigosidade de três STR. Estabeleceram-se alguns eventos de recombinação. Resultados: duas das seis mulheres analisadas mostraram perda de heterozigosidade em três dos dez STR genotipados, indicando seu estado de portadora de deleção neste fragmento do gene da distrofina. Com a segregação familiar dos haplótipos se estabeleceram eventos de recombinação. Conclusões: mediante perda de heterozigosidade é possível estabelecer o estado de portadora de deleção no gene da distrofina com um 100% de certeza. A construção de haplótipos identifica o cromossoma X portador da deleção em familiares do caso índice. Evidenciou-se um evento de recombinação em uma das irmãs do afetado, o que faz indeterminado seu estado de portadora.

Genetic aberrations on the short arm of chromosome 8 (8p) in tongue carcinomas

Aberrations on the short arm of chromosome 8 (8p) are frequently observed in several human cancers. In this study, 20 squamous cell carcinoma (SCC) specimens from the tongue were examined in order to evaluate the role of 8p in SCC of the tongue. Microsatellite analysis using 14 markers demonstrated two commonly deleted regions (CDRs) on 8p. Reverse transcription-polymerase chain reaction (RT-PCR) revealed frequent down-regulation of the FEZ1 gene, mapped to 8p22, and frequent over-expression of the cathepsin B gene, mapped to 8p-21-22. These results suggested that genetic aberrations are involved in the development of SCC of the tongue. However, no significant relationship was observed to be established between the genetic alterations and clinicopathological features. Thus, further investigation is necessary in order to clarify the clinical role of 8p in carcinoma of the tongue.