Whole-Exome Sequencing in Patients Affected by Stevens-Johnson Syndrome and Toxic Epidermal Necrolysis Reveals New Variants Potentially Contributing to the Phenotype.

BACKGROUND: Adverse drug reactions (ADRs) are frequent occurring events that can essentially be defined as harmful or unpleasant symptoms secondary to the use of a medicinal product. ADRs involve a wide spectrum of clinical manifestations ranging from minor itching and rash to life-threatening reactions. Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare ADRs. SJS-TEN may be considered a polygenic pathology due to additive/epistatic effects caused by sequence variants in numerous genes. Next-generation sequencing (NGS) represents a potentially interesting exploration tool in such scenario as it facilitates the simultaneous analysis of large genomic regions and genes at affordable cost. METHODS: The present study has involved using whole-exome sequencing (WES) for the first time on SJS-TEN patients. It involved robust and innovative multistep bioinformatics analysis focusing on 313 candidate genes potentially participating in the disease's aetiology, specific drugs' metabolism and gene regulation. RESULTS: We identified combinations of frequently occurring and rare variants that may contribute to the disease's pathogenesis. Depending on the specific drug being taken, different variants (and alleles) in NAT2, CYP2D8, CYP2B6, ABCC2, UGT2B7 and TCF3 were identified as coherent candidates representing potential future markers for SJS-TEN. CONCLUSION: The present study proposed and has described (for the first time) a large-scale genomic analysis of patients affected by SJS-TEN. The genes and variants identified represent relevant candidates potentially participating in the disease's pathogenesis. Corroborating that proposed by others, we found that complex combinations of frequently occurring and rare variants participating in particular drug metabolism molecular cascades could be associated with the phenotype. TCF3 TF may be considered a coherent candidate for SJS-TEN that should be analysed in new cohorts of patients having ADRs.

Mutant GNLY is linked to Stevens-Johnson syndrome and toxic epidermal necrolysis.

Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare severe cutaneous adverse reactions to drugs. Granulysin (GNLY) plays a key role in keratinocyte apoptosis during SJS/TEN pathophysiology. To determine if GNLY-encoding mutations might be related to the protein's functional disturbances, contributing to SJS/TEN pathogenesis, we performed direct sequencing of GNLY's coding region in a group of 19 Colombian SJS/TEN patients. A GNLY genetic screening was implemented in a group of 249 healthy individuals. We identified the c.11G > A heterozygous sequence variant in a TEN case, which creates a premature termination codon (PTC) (p.Trp4Ter). We show that a mutant protein is synthesised, possibly due to a PTC-readthrough mechanism. Functional assays demonstrated that the mutant protein was abnormally located in the nuclear compartment, potentially leading to a toxic effect. Our results argue in favour of GNLY non-synonymous sequence variants contributing to SJS/TEN pathophysiology, thereby constituting a promising, clinically useful molecular biomarker.

FOXD1 mutations are related to repeated implantation failure, intra-uterine growth restriction and preeclampsia.

BACKGROUND: Human reproductive disorders consist of frequently occurring dysfunctions including a broad range of phenotypes affecting fertility and women's health during pregnancy. Several female-related diseases have been associated with hypofertility/infertility phenotypes, such as recurrent pregnancy loss (RPL). Other occurring diseases may be life-threatening for the mother and foetus, such as preeclampsia (PE) and intra-uterine growth restriction (IUGR). FOXD1 was defined as a major molecule involved in embryo implantation in mice and humans by regulating endometrial/placental genes. FOXD1 mutations in human species have been functionally linked to RPL's origin. METHODS: FOXD1 gene mutation screening, in 158 patients affected by PE, IUGR, RPL and repeated implantation failure (RIF), by direct sequencing and bioinformatics analysis. Plasmid constructs including FOXD1 mutations were used to perform in vitro gene reporter assays. RESULTS: Nine non-synonymous sequence variants were identified. Functional experiments revealed that p.His267Tyr and p.Arg57del led to disturbances of promoter transcriptional activity (C3 and PlGF genes). The FOXD1 p.Ala356Gly and p.Ile364Met deleterious mutations (previously found in RPL patients) have been identified in the present work in women suffering PE and IUGR. CONCLUSIONS: Our results argue in favour of FOXD1 mutations' central role in RPL, RIF, IUGR and PE pathogenesis via C3 and PlGF regulation and they describe, for the first time, a functional link between FOXD1 and implantation/placental diseases. FOXD1 could therefore be used in clinical environments as a molecular biomarker for these diseases in the near future.

Creating and validating a warfarin pharmacogenetic dosing algorithm for Colombian patients.

PURPOSE: Warfarin is an oral anticoagulant associated with adverse reaction to drugs due to wide inter- and intra-individual dosage variability. Warfarin dosage has been related to non-genetic and genetic factors. CYP2C9 and VKORC1 gene polymorphisms affect warfarin metabolism and dosage. Due to the central role of populations' ethnical and genetic origin on warfarin dosage variability, novel algorithms for Latin American subgroups are necessary to establish safe anticoagulation therapy. PATIENTS AND METHODS: We genotyped CYP2C9*2 (c.430C > T), CYP2C9*3 (c.1075A > C), CYP4F2 (c.1297G > A), and VKORC1 (-1639 G > A) polymorphisms in 152 Colombian patients who received warfarin. We evaluated the impact on the variability of patients' warfarin dose requirements. Multiple linear regression analysis, using genetic and non-genetic variables, was used for creating an algorithm for optimal warfarin maintenance dose. RESULTS: Median weekly prescribed warfarin dosage was significantly lower in patients having the VKORC1-1639 AA genotype and poor CYP2C9*2/*2,*2/*3 metabolizers than their wild-type counterparts. We found a 2.3-fold increase in mean dose for normal sensitivity patients (wild-type VKORC1/CYP2C9 genotypes) compared to the other groups (moderate and high sensitivity); 31.5% of the patients in our study group had warfarin sensitivity-related genotypes. The estimated regression equation accounted for 44.4% of overall variability in regard to warfarin maintenance dose. The algorithm was validated, giving 45.9% correlation (R 2=0.459). CONCLUSION: Our results describe and validate the first algorithm for predicting warfarin maintenance in a Colombian mestizo population and have contributed toward the understanding of pharmacogenetics in a Latin American population subgroup.

Transcriptomic analysis of FUCA1 knock-down in keratinocytes reveals new insights into the pathogenesis of fucosidosis skin lesions.

Fucosidosis is a rare lysosomal storage disease which has been classified into two subtypes, depending on the severity of clinical signs and symptoms. Fucosidosis patients' skin abnormalities include angiokeratoma corporis diffusum, widespread telangiectasia, thick skin, hyperhidrosis and hypohidrosis, acrocyanosis and distal transverse nail bands. It has been described that >50% of fucosidosis patients have angiokeratoma. At molecular level, fucosidosis is caused by lysosomal alpha-L-fucosidase (FUCA1) gene mutations. Obtaining samples for functional studies has been challenging due to the inherent difficulty in finding affected individuals. The effect of FUCA1 dysfunction on gene expression is unknown. The aim of this study was to analyse, in keratinocytes, the transcriptomic effect of FUCA1 knock-down for a better understanding of skin lesions' pathogenesis affecting fucosidosis patients. FUCA1 knock-down (siRNA) was performed in human HaCaT immortalised keratinocytes. Affymetrix arrays and qPCR were used for analysing gene expression. Bioinformatics was used for functional clustering of modified genes. In total, 387 genes showed differential expression between FUCA1 silenced and non-silenced cells (222 up-regulated and 165 down-regulated). Up-regulated genes belonged to two major groups: keratinocyte differentiation/epidermal development (n = 17) and immune response (n = 61). Several transcription factors were up-regulated in FUCA1-siRNA transfected cells. This effect might partly have been produced by abnormal transcription factor expression, that is FOXN1. We thus propose that fucosidosis-related skin lesions (eg angiokeratoma) and those of other diseases (eg psoriasis) might be caused by dysfunctions in common aetiological overlapping molecular cascades.

THBD sequence variants potentially related to recurrent pregnancy loss.

Recurrent pregnancy loss (RPL) is a frequently occurring disease, which is classified as idiopathic in more than 50% of cases. THBD, the endothelial cell receptor for thrombin, has been associated with distinct biological processes and considered a coherent RPL-related candidate gene. In the present study, we have sequenced the complete coding region of THBD in 262 patients affected by RPL. Bioinformatics analysis and screening of controls strongly suggested that the THBD-p.Trp153Gly mutation might be related to RPL aetiology. It could be used, after its validation by functional assays, as a molecular marker for diagnostic/prognostic purposes.

Next generation sequencing in women affected by nonsyndromic premature ovarian failure displays new potential causative genes and mutations.

OBJECTIVE: To identify new molecular actors involved in nonsyndromic premature ovarian failure (POF) etiology. DESIGN: This is a retrospective case-control cohort study. SETTING: University research group and IVF medical center. PATIENT(S): Twelve women affected by nonsyndromic POF. The control group included 176 women whose menopause had occurred after age 50 and had no antecedents regarding gynecological disease. A further 345 women from the same ethnic origin (general population group) were also recruited to assess allele frequency for potentially deleterious sequence variants. INTERVENTION(S): Next generation sequencing (NGS), Sanger sequencing, and bioinformatics analysis. MAIN OUTCOME MEASURE(S): The complete coding regions of 70 candidate genes were massively sequenced, via NGS, in POF patients. Bioinformatics and genetics were used to confirm NGS results and to identify potential sequence variants related to the disease pathogenesis. RESULT(S): We have identified mutations in two novel genes, ADAMTS19 and BMPR2, that are potentially related to POF origin. LHCGR mutations, which might have contributed to the phenotype, were also detected. CONCLUSION(S): We thus recommend NGS as a powerful tool for identifying new molecular actors in POF and for future diagnostic/prognostic purposes.

BMP15 c.-9C>G promoter sequence variant may contribute to the cause of non-syndromic premature ovarian failure.

BMP15 has drawn particular attention in the pathophysiology of reproduction, as its mutations in mammalian species have been related to different reproductive phenotypes. In humans, BMP15 coding regions have been sequenced in large panels of women with premature ovarian failure (POF), but only some mutations have been definitely validated as causing the phenotype. A functional association between the BMP15 c.-9C>G promoter polymorphism and cause of POF have been reported. The aim of this study was to determine the potential functional effect of this sequence variant on specific BMP15 promoter transactivation disturbances. Bioinformatics was used to identify transcription factor binding sites located on the promoter region of BMP15. Reverse transcription polymerase chain reaction was used to study specific gene expression in ovarian tissue. Luciferase reporter assays were used to establish transactivation disturbances caused by the BMP15 c.-9C>G variant. The c.-9C>G variant was found to modify the PITX1 transcription factor binding site. PITX1 and BMP15 co-expressed in human and mouse ovarian tissue, and PITX1 transactivated both BMP15 promoter versions (-9C and -9G). It was found that the BMP15 c.-9G allele was related to BMP15 increased transcription, supporting c.-9C>G as a causal agent of POF.

Whole-exome sequencing enables rapid determination of xeroderma pigmentosum molecular etiology.

Xeroderma pigmentosum (XP) is a rare autosomal recessive disorder characterized by extreme sensitivity to actinic pigmentation changes in the skin and increased incidence of skin cancer. In some cases, patients are affected by neurological alterations. XP is caused by mutations in 8 distinct genes (XPA through XPG and XPV). The XP-V (variant) subtype of the disease results from mutations in a gene (XPV, also named POLH) which encodes for Polη, a member of the Y-DNA polymerase family. Although the presence and severity of skin and neurological dysfunctions differ between XP subtypes, there are overlapping clinical features among subtypes such that the sub-type cannot be deduced from the clinical features. In this study, in order to overcome this drawback, we undertook whole-exome sequencing in two XP sibs and their father. We identified a novel homozygous nonsense mutation (c.897T>G, p.Y299X) in POLH which causes the disease. Our results demonstrate that next generation sequencing is a powerful approach to rapid determination of XP genetic etiology.

Sequence analysis of the ADRA2A coding region in children affected by attention deficit hyperactivity disorder.

Attention deficit hyperactivity disorder (ADHD) is a common neurobehavioral pathology characterized by distinct degrees of inattention, hyperactivity and impulsivity. Although ADHD etiology remains elusive, the ADRA2A candidate gene underlies a particular interest, since it participates in the prefrontal cortex regulation of executive function. Three SNPs located on 5' and 3'UTR regions of the gene have been extensively explored but none of them have been definitely validated as a predisposition or a causative sequence variation. In this study, in order to determine whether ADRA2A non-synonymous sequence variants, resulting in biochemical modifications of the protein, are a common cause of the disease we sequenced the complete ADRA2A coding region in a panel of ADHD children of Colombian origin. We identified the c.1138 C>A (p.Arg380Arg) silent substitution. We conclude that ADRA2A non-synonymous sequence variants do not cause ADHD in our sample population. We cannot formerly discard a potential role of this gene during ADHD pathogenesis since only the coding region was analysed. We hope that these results will encourage further researchers to sequence the promoter and coding regions of ADRA2A in large panels of ADHD patients from distinct ethnical origins.

A novel familial case of diffuse leukodystrophy related to NDUFV1 compound heterozygous mutations.

NDUFV1 mutations have been related to encephalopathic phenotypes due to mitochondrial energy metabolism disturbances. In this study, we report two siblings affected by a diffuse leukodystrophy, who carry the NDUFV1 c.1156C>T (p.Arg386Cys) missense mutation and a novel 42-bp deletion. Bioinformatic and molecular analysis indicated that this deletion lead to the synthesis of mRNA molecules carrying a premature stop codon, which might be degraded by the nonsense-mediated decay system. Our results add information on the molecular basis and the phenotypic features of mitochondrial disease caused by NDUFV1 mutations.

Identification and Functional Characterization of GAA Mutations in Colombian Patients Affected by Pompe Disease.

Pompe disease (PD) is a recessive metabolic disorder characterized by acid α-glucosidase (GAA) deficiency, which results in lysosomal accumulation of glycogen in all tissues, especially in skeletal muscles. PD clinical course is mainly determined by the nature of the GAA mutations. Although ~400 distinct GAA sequence variations have been described, the genotype-phenotype correlation is not always evident.In this study, we describe the first clinical and genetic analysis of Colombian PD patients performed in 11 affected individuals. GAA open reading frame sequencing revealed eight distinct mutations related to PD etiology including two novel missense mutations, c.1106 T > C (p.Leu369Pro) and c.2236 T > C (p.Trp746Arg). In vitro functional studies showed that the structural changes conferred by both mutations did not inhibit the synthesis of the 110 kD GAA precursor form but affected the processing and intracellular transport of GAA. In addition, analysis of previously described variants located at this position (p.Trp746Gly, p.Trp746Cys, p.Trp746Ser, p.Trp746X) revealed new insights in the molecular basis of PD. Notably, we found that p.Trp746Cys mutation, which was previously described as a polymorphism as well as a causal mutation, displayed a mild deleterious effect. Interestingly and by chance, our study argues in favor of a remarkable Afro-American and European ancestry of the Colombian population. Taken together, our report provides valuable information on the PD genotype-phenotype correlation, which is expected to facilitate and improve genetic counseling of affected individuals and their families.

CITED2 mutations potentially cause idiopathic premature ovarian failure.

Anomalies in gonadal development in a mouse knockout model of Cited2 have been recently described. In Cited2(-/-) female gonads, an ectopic cell migration was observed and the female program of sex determination was transiently delayed. We hypothesize that, in humans, this temporary inhibition of genes should be sufficient to provoke a developmental impairment of the female gonads, conducive to premature ovarian failure (POF). To establish whether CITED2 mutations are a common cause of the disease, we performed a mutational analysis of this gene in a panel of patients with POF and in a group of control women with normal fertility. We amplified and directly sequenced the complete open reading frame of CITED2 in 139 patients with POF and 290 controls. This study revealed 5 synonymous and 3 nonsynonymous variants. Among these, 7 are novel. The nonsynonymous variant c.604C>A (p.Pro202Thr) was found uniquely in 1 woman from the POF group. In silico analysis of this mutation indicated a potential deleterious effect. We conclude that mutations in CITED2 may be involved in POF pathogenesis.

Screening for mutations of the FOXO4 gene in premature ovarian failure patients.

FOXO4 constitutes a coherent candidate gene associated with premature ovarian failure (POF) pathogenesis. This study sequenced the coding and exon-flanking regions of this gene in a panel of 116 POF patients and 143 controls of Tunisian origin. In both groups, the IVS2 + 41T > G sequence variant was identified. It is concluded that coding mutations of FOXO4 should not be a common cause of the disease in women from the Tunisian population. However, this study cannot exclude that FOXO4 dysfunctions, originated from open reading frame or promoter sequence variations, might be associated with the pathogenesis of the disease in other ethnical groups.

Análisis de deleciones en 15 exones situados dentro y fuera del hot spot mutacional del gen de la distrofina en pacientes con distrofia muscular de Duchenne / Deletion Analysis of 15 exons located outside and inside a “Hot Spot” in the Duchenne Muscular Dystrophy gene in Duchenne’s Muscular dystrophy patients

Introducción. La distrofia muscular de Duchenne (DMD), y su forma alélica más leve, la distrofia muscular de Becker (DMB), es una entidad de herencia recesiva ligada al X, que se presenta con debilidad muscular, pérdida progresiva de las habilidades motoras y muerte precoz. Es causada principalmente por deleciones en el gen de la distrofina, el cual contiene 79 exones. Objetivo. Realizar un análisis ampliado para evaluar la presencia de deleciones en 15 exones del gen de la distrofina situados dentro y fuera del hot spot mutacional en 58 pacientes afectados con DMD/DMB sin mutación previamente identificada. Metodología. Amplificación, mediante PCR múltiplex, de 4 exones situados dentro y 11 fuera del hot spot mutacional descrito para el gen de la distrofina en 58 pacientes afectados con DMD y determinar la frecuencia de deleciones en la población analizada. Resultados. Se encontró deleción del exón 16 en uno de los pacientes estudiados, hecho que indica una frecuencia de 1,7%. No se observó ninguna deleción de los exones situados fuera del hot spot mutacional. Conclusiones. La frecuencia de deleciones en los 15 exones del gen de la distrofina analizados es baja; sólo se presentó en el exón 16, el cual se encuentra localizado en el hot spot mutacional proximal del gen. Es importante analizar este exón en los afectados, en la medida en que aumenta la tasa de detección de deleciones en un 1,7%. Se debe analizar otro tipo de mutaciones como puntuales y duplicaciones en los afectados.

Introduction. Duchenne and Becker Muscular Dystrophies (DMD/DMB) are X-linked recessive diseases characterized by progressive muscle weakness and wasting, loss of motor skills and death after the second decade of life. Deletions are the most prevalent mutations that affect the dystrophin gene, which spans 79 exons. Objective: Identify deletions on the dystrophin gene in 58 patients affected with DMD. Methods: Through multiplex PCR identify deletions on the dystrophin gene in 58 patients with DMD and observe the frequency of this mutation in our population. Results: We found deletions in 1.72% of patients (1 of 58 persons). Deletions were not the principal cause of disease in our population. It is possible that duplications and point mutations caused this illness in our patients. Conclusions: The frequency of deletions in the 15 exons analyzed from the dystrophin gene was low. The predominant types of mutation in our patients` samples were not deletions as has been observed in the literature worldwide, therefore, it is important to determine other types of mutations as are duplications and point mutations.

Utilidad de la citogenética en la medicina actual Visión histórica y aplicación / The utility of cytogenetics in modern medicine Historical view and application

La citogenética es el estudio de los cromosomas tanto en número como en estructura, los primeros pasos en la citogenética humana se dieron a finales del siglo XIX con la publicación de Flemming en 1882 de las primeras ilustraciones del cromosoma humano a partir de observaciones al microscopio, y concluyó con Tjio y Levan en 1953 cuando se determina el número real de cromosomas humanos por célula diploide. La citogenética convencional es una herramienta de gran importancia que permite realizar el diagnóstico cromosómico de pacientes con indicación clínica de cromosomopatía, lo cual les va a permitir asesorar a las familias respecto de dicha enfermedad, su pronóstico y riesgo de recurrencia. El propósito de esta revisión es documentar a los médicos, pediatras, ginecólogos y en general al personal de la salud, de la importancia de los estudios citogenéticos en aquellos casos en que se enfrenten a un paciente con una cromosomopatía o síndrome dismórfico.

Cytogenetics is the study of chromosomes and their numerical and structural abnormalities. In the late 1800´s Flemming published his first illustrations of human chromosomes based on his observations on a microscope. In 1953 Tijo and Levan determined the number of chromosomes in a human somatic cell. From then on, conventional cytogenetics became an important tool for physicians in the diagnosis of patients with chromosomal anomalies through the use of the karyotype. The karyotype thus becomes a means to diagnose patients and provide them genetic counseling. The purpose of this review is to enlighten family doctors, pediatricians and gynecologists and other health practitioners of the importance of cytogenetics when challenged with patients with an abnormal karyotype or dysmorphic syndrome.

Frecuencia de la mutación F508del en estudiantes de la Facultad de Medicina de la Universidad del Rosario, Bogotá, Colombia / Carrier frequency of F508del mutation of cystic fibrosis in medical students from Universidad del Rosario, Bogotá, Colombia

Introducción: La fibrosis quística es la enfermedad letal autosómica recesiva más frecuente en caucásicos, donde su incidencia es de 1 en 2000 nacidos vivos. Se debe a mutaciones en el gen CFTR, de las cuales la más frecuente es la F508del presente en 66% de los enfermos y en 1 de cada 25 personas sanas de origen caucásico. Objetivo: Identificar la tasa de portadores de la mutación F508del en una muestra de estudiantes de la Facultad de Medicina de la Universidad del Rosario.Materiales y métodos: Se determinó la presencia de la mutación F508del mediante PCR y análisis de heterodúplex en 110 estudiantes de IV y VII semestre de la Facultad de Medicina. Resultados: Se obtuvieron 4 heterocigotos para la mutación F508del, es decir, una frecuencia de portadores de 1 en 27 estudiantes. Conclusiones: La frecuencia de portadores de esta mutación en la población analizada es considerable, e indica que hay un alto número de personas en riesgo de heredar la enfermedad y que deben recibir asesoramiento genético. Es necesario aumentar el tamaño de la muestra para obtener datos representativos de la población colombiana.

Introduction: Cystic fibrosis (CF) is the most frequent autosomical recessive disorder in Caucasian population with an incidence of 1 in 2000 newborns. The disease is caused by mutations in the cftr gene, but the most common mutation is F508del, which accounts for 66% of CF chromosomes worldwide and a carrier frequency for Caucasian population of 1 in 25. Objective: To determine the carrier frequency of the F508del mutation in 110 unrelated, healthy students from the Facultad de Medicina, Universidad del Rosario. Methods: The presence of F508del mutation using PCR and heteroduplex analysis was determined. Results: Only four heterozygotes for F508del mutation were discovered. This represents a carrier frequency of 1 in 27 students. Conclusions: This estimated frequency of F508del carriers is higher than expected, encouraging further screening in normal control individuals from different regions of Colombia.

Hemofilia: diagnóstico molecular y alternativas de tratamiento / Hemophilia: molecular diagnosis and alternatives of treatment

La hemofilia es una enfermedad recesiva ligada al cromosoma X que generalmente padecen los hombres. El diagnóstico genético preimplantación (DGP), el diagnóstico prenatal y el diagnóstico molecular de las mutaciones que causan hemofilia, se realizan en investigaciones aisladas con el fin de hacer prevención primaria, asesorar a las portadoras y a sus familias, lo que ha permitido traer al mundo niños libres de esta enfermedad y también mejorar la calidad de vida de los afectados. Los esperanzadores procedimientos en terapia génica (TG) han mostrado gran efectividad, se pretende con ella la producción normal de la proteína que está ausente o alterada en los afectados, pero en el momento los ensayos que se llevan a cabo en seres humanos están detenidos. Aquí se muestran otras terapias alternas que aunque están en fase de investigación, permitirían obtener una producción de proteína a largo término y que se han desarrollado gracias al entendimiento de la naturaleza molecular de los factores de la coagulación.

The haemophilia is a recessive disease tied to the X chromosome that generally men suffer. The genetic preimplantation diagnosis (GPD), the prenatal diagnosis and the molecular diagnosis of the mutations that cause haemophilia, are realized in isolated investigations (researches) in order to do primary prevention, provide advise to the carriers of the disease and their families, which has allowed to bring to the world children free of this disease and also to improve the quality of life of the affected ones. The hopeful procedures in gene therapy (GT) have shown great effectiveness. The intention is to achieve the normal production of the protein which is absent or it is altered in the affected ones, but at the moment the tests carried out in human beings are stopped. Here are other alternate therapies that although are in phase of investigation, would allow to obtain a production of protein to long term and which have been developed thanks to the understanding of the molecular nature of the coagulation factors.

Distrofia muscular de Duchenne y Becker. Una visión molecular / Duchenne and Becker's muscle dystrophy. A molecular vision

La distrofia muscular de Duchenne y Becker es la miopatía más común en ni ños y es causada por la ausencia de la proteína distrofina. Los afectados presentan signos de la enfermedad a edades tempranas de la vida, pierden la habilidad para caminar al comienzo de la segunda década y usualmente, fallecen alrededor de los 20 años de edad. El islamiento del gen defectuoso ha llevado a un mejor entendimiento del proceso de la enfermedad y ha permitido el diagnóstico preciso en los afectados, la posibilidad de asesoramiento genético y diagnóstico prenatal, así como la aplicación de nuevas terapéuticas basadas en el conocimiento de la patogénesis de la enfermedad. El propósito de esta revisión es presentar el progreso hecho en estas áreas, refiriéndonos particularmente a la fisiopatología y al diagnóstico molecular de la enfermedad en Colombia.