Hemofilia: diagnóstico molecular y alternativas de tratamiento
TL;DR: In this paper, otras terapias alternas, aunque estan en fase de investigación, permitirian obtener una produccion de proteina a largo termino and que se han desarrollado gracias al entendimiento de la naturaleza molecular de los factores de la coagulacion.
Abstract: La hemofilia es una enfermedad recesiva ligada al cromosoma X que generalmente padecen los hombres. El diagnostico genetico preimplantacion (DGP), el diagnostico prenatal y el diagnostico molecular de las mutaciones que causan hemofilia, se realizan en investigaciones aisladas con el fin de hacer prevencion primaria, asesorar a las portadoras y a sus familias, lo que ha permitido traer al mundo ninos libres de esta enfermedad y tambien mejorar la calidad de vida de los afectados. Los esperanzadores procedimientos en terapia genica (TG) han mostrado gran efectividad, se pretende con ella la produccion normal de la proteina que esta ausente o alterada en los afectados, pero en el momento los ensayos que se llevan a cabo en seres humanos estan detenidos. Aqui se muestran otras terapias alternas que aunque estan en fase de investigacion, permitirian obtener una produccion de proteina a largo termino y que se han desarrollado gracias al entendimiento de la naturaleza molecular de los factores de la coagulacion.
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TL;DR: The results establish a general overview of population exposure and can be a scientific tool to improve environmental health policies in the country and could strengthen Colombia’s efforts to increase the practice of breastfeeding.
4 citations
TL;DR: In this paper , the authors applied species richness estimation methods from ecology to estimate "variant richness" and determine how many germline pathogenic BRCA1/2 variants have yet to be identified and the frequency of these missing variants in different populations.
Abstract: There have been many surveys of genetic variation in BRCA1 and BRCA2to identify variant prevalence and catalogue population specific variants, yet none have evaluated the magnitude of unobserved variation. We applied species richness estimation methods from ecology to estimate "variant richness" and determine how many germline pathogenic BRCA1/2 variants have yet to be identified and the frequency of these missing variants in different populations. We also estimated the prevalence of germline pathogenic BRCA1/2 variants and identified those expected to be most common. Data was obtained from a literature search including studies conducted globally that tested the entirety of BRCA1/2 for pathogenic variation. Across countries, 45% to 88% of variants were estimated to be missing, i.e., present in the population but not observed in study data. Estimated variant frequencies in each country showed a higher proportion of rare variants compared to recurrent variants. The median prevalence estimate of BRCA1/2 pathogenic variant carriers was 0.64%. BRCA1 c.68_69del is likely the most recurrent BRCA1/2 variant globally due to its estimated prevalence in India. Modeling variant richness using ecology methods may assist in evaluating clinical targeted assays by providing a picture of what is observed with estimates of what is still unknown.
2 citations
Journal Article•
TL;DR: A Colombian family that apparently suffered the two diseases according to clinical diagnosis and the lack of a genetic study to verify and contrast the diagnosis made by health institutions can lead to a wrong classification of von Willebrand disease as a type of mild Hemophilia.
Abstract: El Factor von Willebrand circula en el plasma formando un complejo con el Factor VIII de coagulacion por enlaces no covalentes. Esta interaccion evita la degradacion enzimatica del Factor VIII y asegura su transporte al lugar de formacion del coagulo de fibrina. Debido a su estrecha relacion, la disminucion de la actividad de un factor puede afectar la actividad del otro, lo que genera un diagnostico clinico equivocado en cuanto a que enfermedad se padece, si Hemofilia A o Enfermedad de von Willebrand. Este estudio reporta el caso de una familia colombiana que segun diagnostico clinico de su fenotipo, padecia las dos enfermedades. Sin embargo, dicha familia carecia de un estudio genetico que permitiera verificar y contrastar el diagnostico que hacen las entidades de salud. Por tal razon, se realizo un diagnostico genetico por pruebas moleculares que detectan mutaciones, como las inversiones en los intrones 1 y 22 por PCR de fragmentos largos y la secuenciacion del gen del Factor VIII, esta ultima no aplicada y publicada en Colombia hasta el momento. Se encontraron dos mutaciones sinonimas en los exones 14 y 26 que no alteran la secuencia de aminoacidos en la proteina; por tanto, se descarta la presencia de Hemofilia A en la familia. Se plantea la posibilidad de un caso de Enfermedad de von Willebrand unicamente. El estudio demuestra la necesidad que hay en el pais de ampliar las pruebas clinicas y de incluir el diagnostico genetico en casos de ambiguedad en el diagnostico de estas coagulopatias. Palabras clave: Hemofilia A, Factor VIII, Enfermedad de von Willebrand. MOLECULAR ANALYSIS OF HEMOPHILIA A IN A COLOMBIAN FAMILY WITH DIAGNOSIS OF HEMOPHILIA A AND VON WILLEBRAND DISEASE ABSTRACT Von Willebrand Factor circulates in plasma in a protein complex together with coagulation Factor VIII, joined by noncovalent bonds. This interaction prevents enzymatic degradation of Factor VIII and ensures its transport to the place of the fibrin clot formation. Because of their close relationship, decrease activity of one factor may affect the other one. The late generates a clinical diagnosis not very accurate for Hemophilia A or von Willebrand disease. We report here a Colombian family that apparently suffered the two diseases according to clinical diagnosis. However, the lack of a genetic study to verify and contrast the diagnosis made by health institutions, which is based on phenotype, only, can lead to a wrong classification of von Willebrand disease as a type of mild Hemophilia. The aim of this study was to confirm the clinical diagnosis in this family by molecular analysis. To achieve this, we identify the presence of Factor VIII gene inversions in introns 22 and 1 by LD - PCR and a general scan of the gene for frame shift mutations or stop codons through three family generations. Two synonymous mutations were found in exons 14 and 26, so no changes were observed in the aminoacid sequences, fact that disregards the presence of Hemophilia A. This family could be a case of von Willebrand disease only. The use of molecular techniques to confirm the clinical diagnosis for bleeding disorders will improve adequate treatment and patient prognosis in Colombia. Key words: Hemophilia A, Factor VIII, von Willebrand disease.
2 citations
Cites background from "Hemofilia: diagnóstico molecular y ..."
...Frecuencia de los alelos de referencia y alterno en poblaciones reportadas en NCBI para la variación rs1800292....
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...Frecuencia de los alelos de referencia y alterno en poblaciones reportadas en NCBI para la variación rs1050705....
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...Con ayuda del programa CLC Main Workbench 7 se alinearon las secuencias de cada individuo con la secuencia consenso proporcionada por NCBI (24)....
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...De acuerdo con los resultados arrojados por SIFT y PROVEAN, así como en el reporte de NCBI la variación no afecta la proteína, pues es de tipo sinónima y en consecuencia se mantiene el aminoácido serina (NP_000123....
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...Los alineamientos realizados con el programa CLC Main workbench 7 demostraron la presencia de solo dos variaciones en algunos miembros de la familia, rs1800292 y rs1050705, ya reportadas en bases de datos como NCBI, Kaviar y HAMSTeRS....
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TL;DR: In this paper , a cohort of 165 South African women of self-identified African ancestry diagnosed with breast cancer, who were unselected for family history of cancer, were analyzed using the Illumina TruSight cancer panel for targeted sequencing of 94 cancer susceptibility genes.
Abstract: Abstract Since the discovery of the breast cancer susceptibility genes, BRCA1 and BRCA2, various other genes conferring an increased risk for breast cancer have been identified. Studies to evaluate sequence variants in cancer predisposition genes among women of African ancestry are limited and mostly focused on BRCA1 and BRCA2 . To characterize germline sequence variants in cancer susceptibility genes, we analysed a cohort of 165 South African women of self-identified African ancestry diagnosed with breast cancer, who were unselected for family history of cancer. With the exception of four cases, all others were previously investigated for BRCA1 and BRCA2 deleterious variants, and were negative for pathogenic variants. We utilized the Illumina TruSight cancer panel for targeted sequencing of 94 cancer susceptibility genes. A total of 3.6% of patients carried a pathogenic/likely pathogenic variant in a known breast cancer susceptibility gene: 1.2% in BRCA1 , 0.6% in each of BRCA2 , ATM, CHEK2 and PALB, none of whom had any family history of breast cancer. The mean age of patients who carried deleterious variant in BRCA1/BRCA2 was 39 years and 8 months compared to 47 years and 3 months among women who carried a deleterious variant in other breast cancer susceptibility genes.
1 citations
29 Sep 2020
TL;DR: Hemophilia B or Christmas disease was first differentiated from hemophilia A in 1947 and is linked to the X chromosome; women are carriers, but it manifests clinically in men, although cases of symptomatic women carriers have been described.
Abstract: La hemofilia B o enfermedad de Christmas se diferencio por primera vez de la hemofilia A en 1947. Su forma clasica consiste en un trastorno hereditario de la coagulacion causado por mutaciones en el gen F9, que codifica para el factor IX de la coagulacion. Su herencia esta ligada al cromosoma X; las mujeres son portadoras, pero se manifiesta clinicamente en hombres, aunque se han descrito casos de mujeres portadoras sintomaticas. El factor IX activado es una proteina dependiente de vitamina K, sintetizada en el higado, que forma parte del complejo tenasa, cuya funcion es formar la mayor cantidad de trombina en el nuevo modelo de la coagulacion basado en celulas. De acuerdo a la actividad del factor IX, su deficiencia se puede clasificar en leve (5% a 40%), moderada (1% a 5%), o severa (<1%). Su diagnostico se realiza con la presencia de un TPT alargado que corrige con plasma normal y con la determinacion del nivel funcional del factor IX, y se confirma con el estudio molecular que demuestra la mutacion en el gen F9. Su diagnostico diferencial incluye otras patologias como la hemofilia A. El tratamiento con factor IX recombinante es el mas utilizado en la actualidad, pero se vienen desarrollando nuevas terapias con virus adeno-asociados recombinantes que prometen mejorar la calidad de vida para algunos pacientes afectados. La profilaxis juega un papel fundamental, en particular en los casos de enfermedad moderada y severa
1 citations
References
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Journal Article•
TL;DR: The diagnosis in hemophilia A patients or carriers can be made if intron 22 inversion is present, and the intragenic and extragenic loci hereditary linkage analysis could be used to establish the diagnosis.
Abstract: OBJECTIVE To establish a simple, rapid carrier detection and prenatal diagnosis system for hemophilia A. METHODS Intron 22 inversion in FVIII gene was directly examined by long distance polymerase chain reaction. Polymorphism of factor VIII intragenic RFLP of Bcl I, STR within intron 13 and 22, and extragenic DXS 52 (St 14) VNTR loci by hereditary linkage analysis were assayed. RESULTS The diagnostic rates of these loci were 47.6% (intron 22 inversion), 27.8% (Bcl I), 28.6% and 29.4% (STR within intron 13 and 22), and 81.3% (DXS52), respectively. The overall diagnostic rate in 21 families was 94.7%. CONCLUSIONS The diagnosis in hemophilia A patients or carriers can be made if intron 22 inversion is present. The intragenic and extragenic loci hereditary linkage analysis could be used to establish the diagnosis in intron 22 inversion negative patients.
10 citations
TL;DR: Determination of polymorphisms in VNTR markers revealed that St14 was the most useful for hemophilia A carrier detection in Mexico, and a new 680‐bp allele not previously reported was detected.
Abstract: Variable nucleotide tandem repeats (VNTR) Int13, Int22, and St14 were analyzed to determine polymorphic distribution in normal individuals from Mexico's central region and their efficacy in detecting hemophilia A carriers. Polymerase chain reaction (PCR) was carried out on 166 X chromosomes from unrelated Mexicans, and the same method was applied to detect carriers in hemophilia A families. Screening revealed the existence of at least eight different alleles for Int13, 4 alleles for Int22, and 10 alleles for St14. Their heterozygosity rates were 41.3%, 52.6%, and 83%, respectively. Compared to Caucasians, the Mexican population showed a markedly low heterozygosity rate for the Int13 marker. However, Int22 showed a heterozygosity that was similar to Turkish and Chinese populations. The St14 marker was the most informative in carrier diagnosis, and a new 680-bp allele not previously reported was detected. Carrier diagnosis was performed in 39 women from eight different hemophilia A families. Fifteen (38%) females were not carriers, 16 (41%) females were carriers, and 8 (21%) were homozygous. Determination of polymorphisms in VNTR markers revealed that St14 was the most useful for hemophilia A carrier detection in Mexico.
8 citations
TL;DR: During the genotyping programme of haemophilia B patients, a family from the west of Iran was referred to us and the mutation was first detected in the index case of the family by single‐strand conformation polymorphism (SSCP) technique and applied in carrier detection and prenatal diagnosis for females of this family.
Abstract: Haemophilia B is an X-linked recessive bleeding disorder caused by multiple molecular defects in factor IX gene. During our genotyping programme of haemophilia B patients, a family from the west of Iran was referred to us. We first detected the mutation in the index case of the family by single-strand conformation polymorphism (SSCP) technique. This technique was then applied in carrier detection and prenatal diagnosis for females of this family. Sequencing later revealed the mutation as being G to A at 20519.
6 citations
Journal Article•
TL;DR: Discovery of wide spectrum of mutations in the factor VIII gene and their association with different severity of the disease allowed for development of a rational strategy for mutation detection in clinical settings.
Abstract: SUMMARY Understanding the pathogenesis of haemophilia A has allowed for detailed diagnosis of the condition at a molecular level. Evaluation of the interaction between factor VIII and von Willebrand factor has been utilised to distinguish haemophilia A from von Willebrand disease. The discovery of a wide spectrum of mutations in the factor VIII gene and their association with different severity of the disease has allowed for the development of a rational strategy for mutation detection in clinical settings. Characterisation of the genetic defects is required for carrier detection and antenatal testing, and this also helps to predict risk of factor VIII inhibitor development. Research is ongoing to establish less invasive prenatal testing and to move the testing to pregravid period.
5 citations
TL;DR: Determination of fetal gender from nucleated red blood cells (NRBCs) in maternal blood and attempted to apply prenatal diagnosis of hemophilia A using BclI DNA polymorphism could not verify the validity within the scope of this study.
Abstract: This study demonstrated determination of fetal gender from nucleated red blood cells (NRBCs) in maternal blood and attempted to apply prenatal diagnosis of hemophilia A using BclI DNA polymorphism. Venous blood was drawn from 20 pregnant women, and NRBCs were recovered by magnetic activated cell sorting and anti-GPA (glycophorin A) immunostaining. After microdissector isolation of the NRBCs, primer extension preamplification (PEP) and nested PCR of the amelogenin gene were performed to determine fetal gender. We also performed PEP and nested PCR of BclI polymorphism to verify the validity of prenatal diagnosis of hemophilia A. DNA amplification was achieved in 107 cells (51.9%) and fetal gender determined with 65.0% accuracy. Unfortunately, we could not verify the validity within the scope of this study. However, in a larger number of cases that are informative in BclI polymorphism, we will be able to identify patients affected by hemophilia A using fetal NRBCs in maternal blood.
5 citations