Importancia de la genómica en el diagnóstico de nuevas variantes asociadas a trastornos del tejido conectivo con solapamiento fenotípico

La Aracnodactilia Contractural Congénita  (ACC) es una enfermedad del tejido conectivo de herencia autosómica dominante, causada por variantes en el gen FBN2 que codifica la fibrilina-2. Tiene características específicas como contracturas congénitas, oreja con hélice superior arrugada, camptodactilia, pectus carinatum y complicaciones como escoliosis y la cifoescoliosis. Publicamos el caso de una paciente femenina de 19 años con historia de delgadez, velocidad de crecimiento acelerada, talla alta, pérdida de peso, contracturas articulares, hipotonía congénita, pubertad precoz, hábito marfanoide, pectus carinatum y leve aracnodactilia. Se sospecha de enfermedad del colágeno y se solicita secuenciación del exoma completo mediante NGS  (del inglés Next Generation Sequencing) + CNVs  (del inglés Copy Number Variations) genes relacionados con colagenopatías; se identificó una variante en el gen FBN2  (NM_001999.4): c.4394G>A; p.Cys1465Tyr; estado heterocigoto de significancia clínica probablemente patogénica. La ACC es fenotípicamente similar al síndrome de Marfán y se caracteriza por aracnodactilia, dolicostenomelia, escoliosis, contracturas congénitas múltiples y anomalías de los oídos externos. A diferencia del síndrome de Marfán; no tiene compromiso ocular ni afecta la raíz aórtica. Cuenta con variabilidad fenotípica que le dan la heterogeneidad que pueden interferir y retrasar el proceso diagnóstico y terapéutico específico al solaparse con otras condiciones médicas. Los avances en la medicina y la genómica con la utilización de nuevos métodos diagnósticos han permitido que cada día nos acerquemos más a la medicina 6P  (precisión, predicción, prevención, personalizada, participativa con enfoque poblacional) que impacta en el diagnóstico, tratamiento específico, seguimiento, pronóstico y adecuado asesoramiento genético de las enfermedades. (provisto por Infomedic International)

Contractural arachnodactyly congenita  (CCA) is an autosomal dominantly inherited connective tissue disease caused by variants in the FBN2 gene encoding fibrillin-2. It has specific features such as congenital contractures, wrinkled upper helix ear, camptodactyly, pectus carinatum and complications such as scoliosis and kyphoscoliosis. We publish the case of a 19-year-old female patient with a history of thinness, accelerated growth velocity, tall stature, weight loss, joint contractures, congenital hypotonia, precocious puberty, marfanoid habitus, pectus carinatum and mild arachnodactyly. Collagen disease was suspected and whole exome sequencing by NGS  (Next Generation Sequencing) + CNVs  (Copy Number Variations) genes related to collagenopathies was requested; a variant was identified in the FBN2 gene  (NM_001999.4): c.4394G>A; p.Cys1465Tyr; heterozygous state of probably pathogenic clinical significance. CCA is phenotypically similar to Marfan syndrome and is characterized by arachnodactyly, dolichostenomelia, scoliosis, multiple congenital contractures, and external ear anomalies. Unlike Marfan syndrome, it has no ocular involvement and does not affect the aortic root. It has phenotypic variability that gives it heterogeneity that can interfere and delay the specific diagnostic and therapeutic process by overlapping with other medical conditions. Advances in medicine and genomics with the use of new diagnostic methods have allowed us to get closer to 6P medicine  (precision, prediction, prevention, personalized, participatory with a population approach) that impacts on the diagnosis, specific treatment, follow-up, prognosis and adequate genetic counseling of diseases. (provided by Infomedic International)

Introducción al filtrado, análisis y curación de variantes genéticas en pacientes con Discapacidad Intelectual / Introduction to filtering, analysis and curation of genetic variants in patients with Intellectual Disability

Resumen Actualmente la secuenciación del exoma completo (WES; Whole-exome sequencing) mediante la técnica NGS (Next-generation sequencing) es uno de los estudios genéticos más solicitados dentro del abordaje de pacientes con Discapacidad Intelectual con o sin otras anomalías. Al igual que con otros proce dimientos y estudios clínicos, es conveniente que los médicos prescriptores tengan una comprensión clara de los alcances y limitaciones del uso de WES, del proceso de análisis de las variantes genéticas identificadas, así como de aspectos a evaluar acerca de la calidad y estructura de los informes de los estudios de NGS, con el objetivo de que puedan interpretar mejor los resultados de un estudio y plantear de la mejor manera la correlación de los mismos con la clínica observada.

Abstract Currently, Whole exome sequencing (WES) using NGS (Next-generation sequencing) technology is one of the most requested genetic studies within the approach of patients with intellectual disability with or without other anomalies. As with other procedures and clinical studies, it is convenient for prescribing physicians to have a clear understanding of the scope and limitations of the use of WES, the analysis process of the genetic variants identified, as well as aspects to be evaluated regarding quality and structure of the reports of the NGS studies, with the aim that they can better interpret the results of a study, evaluate its quality, and propose in the best way the correlation of the same with the observed phenotype.

Novel Pathogenic Mutation Mapping of ASPM Gene in Consanguineous Pakistani Families with Primary Microcephaly

Abstract Autosomal recessive primary microcephaly (MCPH) is a neurodevelopmental disorder characterized by a congenitally reduced head circumference (-3 to -5 SD) and non-progressive intellectual disability. The objective of the study was to evaluate pathogenic mutations in the ASPM gene to understand etiology and molecular mechanism of primary microcephaly. Blood samples were collected from various families across different remote areas of Pakistan from February 2017 to May 2019 who were identified to be affected with primary microcephaly. DNA extraction was performed using the salting-out method; the quality and quantity of DNA were evaluated using spectrophotometry and 1% agarose gel electrophoresis, respectively in University of the Punjab. Mutation analysis was performed by whole exome sequencing from the Cologne Center for Genomics, University of Cologne. Sanger sequencing was done in University of the Punjab to confirm the pathogenic nature of mutation. A novel 4-bp deletion mutation c.3877_3880delGAGA was detected in exon 17 of the ASPM gene in two primary microcephaly affected families (A and B), which resulted in a frame shift mutation in the gene followed by truncated protein synthesis (p.Glu1293Lysfs*10), as well as the loss of the calmodulin-binding IQ domain and the Armadillo-like domain in the ASPM protein. Using the in-silico tools Mutation Taster, PROVEAN, and PolyPhen, the pathogenic effect of this novel mutation was tested; it was predicted to be disease causing, with high pathogenicity scores. One previously reported mutation in exon 24 (c.9730C>T) of the ASPM gene resulting in protein truncation (p.Arg3244*) was also observed in family C. Mutations in the ASPM gene are the most common cause of MCPH in most cases. Therefore, enrolling additional affected families from remote areas of Pakistan would help in identifying or mapping novel mutations in the ASPM gene of primary microcephaly.

Resumo Microcefalia primária autossômica recessiva (MCPH) é um distúrbio do neurodesenvolvimento caracterizado por uma redução congênita do perímetro cefálico (-3 a -5 DP) e deficiência intelectual não progressiva. O objetivo do estudo foi avaliar mutações patogênicas no gene ASPM a fim de compreender a etiologia e o mecanismo molecular da microcefalia primária. Amostras de sangue foram coletadas de várias famílias em diferentes áreas remotas do Paquistão de fevereiro de 2017 a maio de 2019, que foram identificadas como afetadas com microcefalia primária. A extração do DNA foi realizada pelo método salting-out; a qualidade e a quantidade de DNA foram avaliadas por espectrofotometria e eletroforese em gel de agarose a 1%, respectivamente, na Universidade de Punjab. A análise de mutação foi realizada por sequenciamento completo do exoma do Cologne Center for Genomics, University of Cologne. O sequenciamento de Sanger foi feito na Universidade do Punjab para confirmar a natureza patogênica da mutação. Uma nova mutação de deleção de 4 bp c.3877_3880delGAGA foi detectada no exon 17 do gene ASPM em duas famílias afetadas por microcefalia primária (A e B), que resultou em uma mutação de frame shift no gene seguida por síntese de proteína truncada (pGlu1293Lysfs * 10), bem como a perda do domínio IQ de ligação à calmodulina e o domínio do tipo Armadillo na proteína ASPM. Usando as ferramentas in-silico Mutation Taster, PROVEAN e PolyPhen, o efeito patogênico dessa nova mutação foi testado; foi previsto ser causador de doenças, com altos escores de patogenicidade. Uma mutação relatada anteriormente no exon 24 (c.9730C > T) do gene ASPM, resultando em truncamento de proteína (p.Arg3244 *) também foi observada na família C. Mutações no gene ASPM são a causa mais comum de MCPH na maioria dos casos . Portanto, a inscrição de famílias afetadas adicionais de áreas remotas do Paquistão ajudaria a identificar ou mapear novas mutações no gene ASPM da microcefalia primária.

Novel Pathogenic Mutation Mapping of ASPM Gene in Consanguineous Pakistani Families with Primary Microcephaly / Novo mapeamento de mutações patogênicas do gene ASPM em famílias consanguíneas com microcefalia primária do Paquistão

Abstract Autosomal recessive primary microcephaly (MCPH) is a neurodevelopmental disorder characterized by a congenitally reduced head circumference (-3 to -5 SD) and non-progressive intellectual disability. The objective of the study was to evaluate pathogenic mutations in the ASPM gene to understand etiology and molecular mechanism of primary microcephaly. Blood samples were collected from various families across different remote areas of Pakistan from February 2017 to May 2019 who were identified to be affected with primary microcephaly. DNA extraction was performed using the salting-out method; the quality and quantity of DNA were evaluated using spectrophotometry and 1% agarose gel electrophoresis, respectively in University of the Punjab. Mutation analysis was performed by whole exome sequencing from the Cologne Center for Genomics, University of Cologne. Sanger sequencing was done in University of the Punjab to confirm the pathogenic nature of mutation. A novel 4-bp deletion mutation c.3877_3880delGAGA was detected in exon 17 of the ASPM gene in two primary microcephaly affected families (A and B), which resulted in a frame shift mutation in the gene followed by truncated protein synthesis (p.Glu1293Lysfs*10), as well as the loss of the calmodulin-binding IQ domain and the Armadillo-like domain in the ASPM protein. Using the in-silico tools Mutation Taster, PROVEAN, and PolyPhen, the pathogenic effect of this novel mutation was tested; it was predicted to be "disease causing," with high pathogenicity scores. One previously reported mutation in exon 24 (c.9730C>T) of the ASPM gene resulting in protein truncation (p.Arg3244*) was also observed in family C. Mutations in the ASPM gene are the most common cause of MCPH in most cases. Therefore, enrolling additional affected families from remote areas of Pakistan would help in identifying or mapping novel mutations in the ASPM gene of primary microcephaly.

Resumo Microcefalia primária autossômica recessiva (MCPH) é um distúrbio do neurodesenvolvimento caracterizado por uma redução congênita do perímetro cefálico (-3 a -5 DP) e deficiência intelectual não progressiva. O objetivo do estudo foi avaliar mutações patogênicas no gene ASPM a fim de compreender a etiologia e o mecanismo molecular da microcefalia primária. Amostras de sangue foram coletadas de várias famílias em diferentes áreas remotas do Paquistão de fevereiro de 2017 a maio de 2019, que foram identificadas como afetadas com microcefalia primária. A extração do DNA foi realizada pelo método salting-out; a qualidade e a quantidade de DNA foram avaliadas por espectrofotometria e eletroforese em gel de agarose a 1%, respectivamente, na Universidade de Punjab. A análise de mutação foi realizada por sequenciamento completo do exoma do Cologne Center for Genomics, University of Cologne. O sequenciamento de Sanger foi feito na Universidade do Punjab para confirmar a natureza patogênica da mutação. Uma nova mutação de deleção de 4 bp c.3877_3880delGAGA foi detectada no exon 17 do gene ASPM em duas famílias afetadas por microcefalia primária (A e B), que resultou em uma mutação de frame shift no gene seguida por síntese de proteína truncada (pGlu1293Lysfs * 10), bem como a perda do domínio IQ de ligação à calmodulina e o domínio do tipo Armadillo na proteína ASPM. Usando as ferramentas in-silico Mutation Taster, PROVEAN e PolyPhen, o efeito patogênico dessa nova mutação foi testado; foi previsto ser "causador de doenças", com altos escores de patogenicidade. Uma mutação relatada anteriormente no exon 24 (c.9730C > T) do gene ASPM, resultando em truncamento de proteína (p.Arg3244 *) também foi observada na família C. Mutações no gene ASPM são a causa mais comum de MCPH na maioria dos casos . Portanto, a inscrição de famílias afetadas adicionais de áreas remotas do Paquistão ajudaria a identificar ou mapear novas mutações no gene ASPM da microcefalia primária.

Novel Pathogenic Mutation Mapping of ASPM Gene in Consanguineous Pakistani Families with Primary Microcephaly / Novo mapeamento de mutações patogênicas do gene ASPM em famílias consanguíneas com microcefalia primária do Paquistão

Autosomal recessive primary microcephaly (MCPH) is a neurodevelopmental disorder characterized by a congenitally reduced head circumference (-3 to -5 SD) and non-progressive intellectual disability. The objective of the study was to evaluate pathogenic mutations in the ASPM gene to understand etiology and molecular mechanism of primary microcephaly. Blood samples were collected from various families across different remote areas of Pakistan from February 2017 to May 2019 who were identified to be affected with primary microcephaly. DNA extraction was performed using the salting-out method; the quality and quantity of DNA were evaluated using spectrophotometry and 1% agarose gel electrophoresis, respectively in University of the Punjab. Mutation analysis was performed by whole exome sequencing from the Cologne Center for Genomics, University of Cologne. Sanger sequencing was done in University of the Punjab to confirm the pathogenic nature of mutation. A novel 4-bp deletion mutation c.3877_3880delGAGA was detected in exon 17 of the ASPM gene in two primary microcephaly affected families (A and B), which resulted in a frame shift mutation in the gene followed by truncated protein synthesis (p.Glu1293Lysfs*10), as well as the loss of the calmodulin-binding IQ domain and the Armadillo-like domain in the ASPM protein. Using the in-silico tools Mutation Taster, PROVEAN, and PolyPhen, the pathogenic effect of this novel mutation was tested; it was predicted to be "disease causing", with high pathogenicity scores. One previously reported mutation in exon 24 (c.9730C>T) of the ASPM gene resulting in protein truncation (p.Arg3244*) was also observed in family C. Mutations in the ASPM gene are the most common cause of MCPH in most cases. Therefore, enrolling additional affected families from remote areas of Pakistan would help in identifying or mapping novel mutations in the ASPM gene of primary microcephaly.

Microcefalia primária autossômica recessiva (MCPH) é um distúrbio do neurodesenvolvimento caracterizado por uma redução congênita do perímetro cefálico (-3 a -5 DP) e deficiência intelectual não progressiva. O objetivo do estudo foi avaliar mutações patogênicas no gene ASPM a fim de compreender a etiologia e o mecanismo molecular da microcefalia primária. Amostras de sangue foram coletadas de várias famílias em diferentes áreas remotas do Paquistão de fevereiro de 2017 a maio de 2019, que foram identificadas como afetadas com microcefalia primária. A extração do DNA foi realizada pelo método salting-out; a qualidade e a quantidade de DNA foram avaliadas por espectrofotometria e eletroforese em gel de agarose a 1%, respectivamente, na Universidade de Punjab. A análise de mutação foi realizada por sequenciamento completo do exoma do Cologne Center for Genomics, University of Cologne. O sequenciamento de Sanger foi feito na Universidade do Punjab para confirmar a natureza patogênica da mutação. Uma nova mutação de deleção de 4 bp c.3877_3880delGAGA foi detectada no exon 17 do gene ASPM em duas famílias afetadas por microcefalia primária (A e B), que resultou em uma mutação de frame shift no gene seguida por síntese de proteína truncada (pGlu1293Lysfs * 10), bem como a perda do domínio IQ de ligação à calmodulina e o domínio do tipo Armadillo na proteína ASPM. Usando as ferramentas in-silico Mutation Taster, PROVEAN e PolyPhen, o efeito patogênico dessa nova mutação foi testado; foi previsto ser "causador de doenças", com altos escores de patogenicidade. Uma mutação relatada anteriormente no exon 24 (c.9730C > T) do gene ASPM, resultando em truncamento de proteína (p.Arg3244 *) também foi observada na família C. Mutações no gene ASPM são a causa mais comum de MCPH na maioria dos casos . Portanto, a inscrição de famílias afetadas adicionais de áreas remotas do Paquistão ajudaria a identificar ou mapear novas mutações no gene ASPM da microcefalia primária.

Preliminary identification of pathogenic variants in an Afro-Colombian Raizal family with risk factors for glaucoma / Identificación preliminar de variantes patógenas en una familia raizal afrocolombiana con factores de riesgo para glaucoma

Abstract Objective: To identify pathogenic variants in an Afro-Colombian Raizal family with risk factors for glaucoma. Methods: In the present study, whole exome sequencing was performed on seven members of a Raizal family from the archipelago of San Andrés, Providencia, and Santa Catalina, in the Caribbean region of Colombia. Four of them had been diagnosed with glaucoma. In addition, two healthy volunteers from the island were included. Results: Of the 198 single nucleotide variants associated with glaucoma, previously reported by the DisGeNET database, four were identified in members of the Raizal family: rs11938093, rs7336216, rs3817672, and rs983034. Furthermore, single nucleotide variant rs983034 was identified in the Wnt ligand secretion mediator gene in all members of the family but not in healthy volunteers. Notably, WLS dysfunctions have been linked to pathology in the trabecular meshwork of the eye. Trabecular meshwork is an important regulator of the outflow of aqueous humor that maintains intraocular pressure (intraocular pressure) at normal levels. Damage to trabecular meshwork is associated with ocular hypertension, which leads to glaucoma progression. In relation to the other single nucleotide variants that were identified, their presence was confirmed in some members of the Raizal family. However, it is still unclear the pathophysiological cause that associates these single nucleotide variants with glaucoma. Conclusions: It was possible to identify four non-synonymous single nucleotide variants that predict significant damage to the structure and function of genes associated with glaucoma pathology in an Afro-Colombian.

Resumen Objetivo: Identificar las variantes patogénicas en una familia raizal afrocolombiana con factores de riesgo para el glaucoma. Métodos: En el presente estudio, se realizó una secuenciación de exoma completo en siete miembros de una familia Raizal del archipiélago de San Andrés, Providencia y Santa Catalina del Caribe colombiano. La mitad de ellos habían sido diagnosticados con glaucoma. Además, se incluyeron dos voluntarios sanos de la isla. Resultados: De las 198 variantes de un solo nucleótido (SNV) asociadas con el glaucoma, previamente informadas por la base de datos DisGeNET, se identificaron cuatro en los miembros de la familia Raizal: rs11938093, rs7336216, rs3817672 y rs983034. Ademas, en todos los miembros de la familia, pero no en voluntarios sanos, se identificó SNV rs983034 en el gen mediador de secreción de ligando Wnt (WLS). Notablemente, las disfunciones WLS se han relacionado con patologías en la red trabecular (TM) del ojo. TM es un regulador importante del flujo de salida del humor acuoso que mantiene la presión intraocular (presión intraocular) en niveles normales. El daño a la TM se asocia con hipertensión ocular que conduce a la progresión del glaucoma. En relación con los demás SNV identificados, se constató su presencia en algunos miembros de la familia Raizal. Sin embargo, aún no está clara la causa fisiopatológica que asocia estas SNV con el glaucoma. Conclusiones: Fue posible identificar cuatro SNVs no sinónimos con predicción de daño significativo en la estructura y función de genes asociados a patología de glaucoma en un afrocolombiano.

Análisis clínico, molecular y bioinformático de paciente con enfermedad de Cori-Forbes en el Suroccidente Colombiano / Clinical, molecular and bioinformatic analysis a patient with Cori-Forbes disease in the Southwest of Colombia

Introducción: La enfermedad por almacenamiento del glucógeno tipo III (GSDIII, Glycogen storage disease type III) o Enfermedad de Cori Forbes es un trastorno del proceso de glucogenólisis ocasionado por variantes del gen AGL que codifica la enzima desramificante del glucógeno; se encuentra ubicado en el cromosoma 1p21.2 y su alteración genera una degradación incompleta del glucógeno, llevando a una acumulación de dextrina límite en órganos blanco, ocasionando organomegalia y disfunción. Objetivo: Caracterizar molecularmente un paciente lactante mayor con diagnóstico clínico y bioquímico sospechoso de GSDIII. Materiales y Métodos: Paciente lactante mayor masculino con antecedente de displasia broncopulmonar, infección respiratoria aguda, reflujo gastroesofágico, hepatomegalia e intolerancia a la lactosa. Se realizó estudio molecular mediante secuenciación de exoma completo; las variantes reportadas fueron evaluadas por Software de predicción como: Mutation Tas-ter, PROVEAN, UMD-Predictor, POLYPHEN, SIFT, Human Splicing Finder. Finalmente, se realizó una red de interacción génica mediante el programa GeneMania para determinar asociaciones génicas cercanas. Resultados: Se identifi caron 3 variantes heterocigotas ubicadas en el gen AGL: p.Arg910* que ocasiona pérdida del dominio amilo-1,6 glucosidasa y el dominio de unión al glucógeno, y las variantes p.Trp373Cys, p.Asn565Ser que generan cambios missense en la proteína. El análisis de significancia clínica por medio de métodos in-sílico determinó una clasificación patogénica para todas las variantes. La red de interacción permitió observar asociaciones entre el gen AGL y los genes FOXA2, PPP1R3B, NHLRC1 y GCK, que tienen relación con procesos metabólicos. Conclusión: una sospecha clínica inicial, a través de una buena historia clínica y la pertinencia de estudios bioquímicos-metabólicos-genómicos dirigidos, permite brindar un correcto diagnóstico, tratamiento y seguimiento, acercándonos a la medicina de precisión.

Introduction: Glycogen storage disease type III (GSDIII) or Cori Forbes disease is a disorder of the glycogeno-lysis process caused by variants of the AGL gene that encodes the glycogen debranching enzyme; It is located on chromosome 1p21.2 and its alteration generate an incomplete degradation of glycogen, leading to an accumu-lation of borderline dextrin in target organs, causing organomegaly and dysfunction. Objective: To characterize at the molecular level an elderly male lactating patient from southwestern Colombia with a clinical, biochemical diagnosis suspected of GSDIII. Materials and methods: An elderly male infant with a history of bronchopul-monary dysplasia, acute respiratory infection, gastroesophageal refl ux, hepatomegaly, and lactose intolerance. A molecular study was performed by whole exome sequencing; the reported variants were evaluated by prediction software such as Mutation Taster, PROVEAN, UMD-Predictor, POLYPHEN, SIFT, Human Splicing Finder. Fi-nally, a gene interaction network was performed using the GeneMania program to determine close gene associa-tions. Results: 3 heterozygous variants located in the AGL gene were identifi ed: p.Arg910 * that causes loss of the amyl-1,6 glucosidase domain and the glycogen-binding domain, and the variants p.Trp373Cys, p.Asn565 in the protein. The analysis of clinical signifi cance by means of in-silico methods determined a pathogenic classifi cation for all the variants. The interaction network will observe associations between the AGL gene and the FOXA2, PPP1R3B, NHLRC1 and GCK genes, which are related to metabolic processes. Conclusion: an initial clinical suspicion, through a good clinical history and the relevance of directed biochemical-metabolic-genomic studies, allows us to provide a correct diagnosis, treatment, and follow-up, bringing us closer to precision medicine

Molecular study of sticky platelet syndrome using exorne sequencing / Estudio molecular del síndrome de plaqueta pegajosa mediante secuenciación del exoma

Abstract Introduction: Sticky platelet syndrome (SPS) is a prothrombotic condition characterized by increased platelet aggregation that causes arterial and venous thrombosis. Its diagnosis is reached by identifying increased aggregation using low concentrations of adenosine diphosphate and epinephrine in platelet aggregation tests. Objectives: To identify common mutations through exome sequencing in two patients from the same family diagnosed with SPS and, thus, contribute to the molecular study of this disease. Materials and methods: Descriptive study. In January 2018, exome sequencing was performed in a 10-year-old patient treated at Fundación HOMI (Bogotá D.C., Colombia), index case, and in one of his adult first-degree relatives, both with a history of thrombotic disease and diagnosed with SPS. Exome sequencing was performed at the Complexo Hospitalario Universitario de Santiago de Compostela (Spain) using the SureSelect Clinical Research Exome V2 software by Agilent. Results: Exome sequencing led to detect genetic variants in both cases when compared with the reference sequence. The following variant was identified in the two samples: a cytosine to thymine transition at position c.236 (NM_000174.4) of the glycoprotein (GP)Ib-IX-V complex platelet membrane receptor, which causes a heterozygous transition of the amino acid threonine to isoleucine (i.e., a transition from hydrophilic amino acid to a hydrophobic amino acid) at position p. 79 of the extracellular leucine-rich repeat domain of GPIba subunit of the (GP)Ib-IX complex, involving a conformational change of the main receptor of ligands IB alpha, which might result in platelet hyperaggregation and thrombosis. This variant has not been described in patients with SPS to date. Conclusion: The mutation identified in both samples could be related to SPS considering the importance of glycoprotein IX in platelet function.

Resumen Introducción. El síndrome de plaqueta pegajosa (SPP) es una condición protrombótica caracterizada por un incremento de la agregabilidad plaquetaria que causa trombosis arterial y venosa. Su diagnóstico se realiza al identificar el aumento de la agregabilidad utilizando bajas concentraciones de adenosín difosfato y epinefrina en pruebas de agregación plaquetaria. Objetivos. Identificar mutaciones comunes mediante secuenciación del exoma en dos pacientes de una misma familia con diagnóstico de SPP y, de esta forma, contribuir al estudio molecular de esta enfermedad. Materiales y métodos. Estudio descriptivo en el que se realizó secuenciación del exoma en un paciente de 10 años atendido en la Fundación HOMI (Bogotá, Colombia), caso índice, y en uno de sus familiares adultos en primer grado, ambos con antecedente de enfermedad trombótica y diagnosticados con SPP. La secuenciación del exoma se realizó en el Complexo Hospitalario Universitario de Santiago de Compostela (España) con el programa SureSelect Clinical Research Exome V2 de Agilent. Resultados. En la secuenciación del exoma se detectaron variantes genéticas en ambos casos en comparación con la secuencia de referencia. En las muestras de ambos pacientes se identificó una variante heterocigota consistente en una transición de citosina a timina en la posición c.236 (NM_000174.4) que provoca el cambio del aminoácido treonina por isoleucina en la posición p.79 del dominio extracelular repetitivo rico en leucina (subunidad GPIba del complejo de la glicoproteína Ib-IX-V) y que podría provocar el cambio conformacional del receptor principal del ligando Ib alfa, así como hiperagregación plaquetaria y trombosis. Esta variante no ha sido descrita previamente en pacientes con SPP. Conclusión. La mutación identificada en las muestras estudiadas podría estar relacionada con el SPP considerando la importancia de la glicoproteína IX en las funciones plaquetarias.

Una nueva mutación asociada con el síndrome de Pierson / A new mutation associated with Pierson syndrome

El síndrome de Pierson se caracteriza por la presencia de síndrome nefrótico congénito y microcoria bilateral. Genéticamente, este trastorno está ocasionado por mutaciones en el gen LAMB2, que codifica la cadenaß2 de la laminina. Hasta la fecha, en la bibliografía se informaron 98casos y 50mutaciones diferentes. No existen terapias específicas para el síndrome de Pierson, y el tratamiento es complementario. El pronóstico es malo por la disfunción renal progresiva y las complicaciones de la insuficiencia renal. En este artículo, se informa sobre una mutación homocigota novedosa (c.1890G>C [p.Q630H]) en el gen LAMB2 en una paciente con síndrome de Pierson que tenía un fenotipo atípico, como epidermólisis ampollosa.

Pierson syndrome is characterized by congenital nephrotic syndrome and bilateral microcoria. Genetically, mutations in the LAMB2 gene, which encodes the laminin ß2 chain, lead to this disorder. To date, 98 cases and 50 different mutations have been reported in literature. There are no specific therapies for Pierson syndrome and treatment is supportive. The prognosis is poor because of progressive impairment of renal function and complications of renal failure. We report a novel homozygous mutation (c.1890G>T, p.Q630H) in the LAMB2 gene in a patient with Pierson syndrome who had atypical phenotypic feature such as epidermolysis bullosa

Wiedemann-Steiner syndrome with a novel pathogenic variant in KMT2A: a case report / Síndrome de Wiedemann-Steiner por una nueva variante patogénica en KMT2A: reporte de un caso

Abstract Case Description: We report the case of a one-year-old girl who was diagnosed with Wiedemann-Steiner Syndrome based on the identification of a novel de novo frameshift mutation in the KMT2A gene by whole exome sequencing and supported by her clinical features. Clinical Findings: KMT2A mutations cause Wiedemann-Steiner Syndrome, a very rare genetic disorder characterized by congenital hypertrichosis, short stature, intellectual disability, and distinct facial features. Treatment and Outcome: Whole exome sequencing identified a novel frameshift variant: c. 4177dupA (p.Ile1393Asnfs * 14) in KMT2A; this change generates an alteration of the specific binding to non-methylated CpG motifs of the DNA to the protein. The genotype and phenotype of the patient were compared with those of earlier reported patients in the literature. Clinical Relevance: In diseases with low frequency, it is necessary to establish a genotype-phenotype correlation that allows the establishment of therapeutic and follow-up goals. The phenotype comparation with other reported cases did not show differences attributable to sex or age among patients with Wiedemann-Steiner Syndrome. Whole exome sequencing allows identifying causality in conditions with high clinical and genetic heterogeneity like hypertrichosis.

Resumen Descripción del caso: Se reporta el caso de una paciente femenina de un año de edad, diagnosticada con Síndrome de Wiedemann-Steiner basado en la identificación de una nueva variante patogénica de novo de tipo frameshift en el gen KMT2A Mediante secuenciación de exoma usando el enfoque de trio, sumado a sus características clínicas. Hallazgos clínicos: las mutaciones en KMT2A causan el Síndrome de Wiedemann-Steiner, un desorden genético muy raro caracterizado por hipertricosis congénita, talla baja, retardo mental variable y fenotipo facial distintivo, los cuales se encuentran en la paciente reportada. Resultado: La Secuenciación de exoma completo encontró una variante de tipo frameshift: c.4177dupA (p. Ile1393Asnfs * 14) en KMT2A, este cambio a nivel génico genera una alteración de la unión específica a motivos CpG no metilados del DNA a la proteína. El genotipo y el fenotipo de la paciente fue comparado con los pacientes reportados previamente en la literatura. Relevancia clínica: En enfermedades con baja frecuencia como la aquí reportada es necesario establecer correlaciones genotipo-fenotipo que permitan establecer planes terapéuticos y de seguimiento. El análisis realizado no evidenció diferencias atribuibles a sexo o edad entre los pacientes diagnosticados con Síndrome de Weidemann-Steiner. La secuenciación de exoma permitió identificar causalidad en este caso, cuya característica principal de hipertricosis se asocia con alta heterogeneidad clínica y genética.