Retinal Degeneration Associated With RPGRIP1: A Review of Natural History, Mutation Spectrum, and Genotype-Phenotype Correlation in 228 Patients.

Purpose: RPGRIP1 encodes a ciliary protein expressed in the photoreceptor connecting cilium. Mutations in this gene cause ∼5% of Leber congenital amaurosis (LCA) worldwide, but are also associated with cone-rod dystrophy (CRD) and retinitis pigmentosa (RP) phenotypes. Our purpose was to clinically characterize RPGRIP1 patients from our cohort, collect clinical data of additional RPGRIP1 patients reported previously in the literature, identify common clinical features, and seek genotype-phenotype correlations. Methods: Clinical data were collected from 16 patients of our cohort and 212 previously reported RPGRIP1 patients and included (when available) family history, best corrected visual acuity (BCVA), refraction, comprehensive ocular examination, optical coherence tomography (OCT) imaging, visual fields (VF), and full-field electroretinography (ffERG). Results: Out of 228 patients, the majority (197, 86%) were diagnosed with LCA, 18 (7%) with RP, and 13 (5%) with CRD. Age of onset was during early childhood (n = 133, average of 1.7 years). All patients but 6 had moderate hyperopia (n = 59, mean of 4.8D), and average BCVA was 0.06 Snellen (n = 124; only 10 patients had visual acuity [VA] > 0.10 Snellen). On funduscopy, narrowing of blood vessels was noted early in life. Most patients had mild bone spicule-like pigmentation starting in the midperiphery and later encroaching upon the posterior pole. OCT showed thinning of the outer nuclear layer (ONL), while cystoid changes and edema were relatively rare. VF were usually very constricted from early on. ffERG responses were non-detectable in the vast majority of cases. Most of the mutations are predicted to be null (363 alleles), and 93 alleles harbored missense mutations. Missense mutations were identified only in two regions: the RPGR-interacting domain and the C2 domains. Biallelic null mutations are mostly associated with a severe form of the disease, whereas biallelic missense mutations usually cause a milder disease (mostly CRD). Conclusion: Our results indicate that RPGRIP1 biallelic mutations usually cause severe retinal degeneration at an early age with a cone-rod pattern. However, most of the patients exhibit preservation of some (usually low) BCVA for a long period and can potentially benefit from gene therapy. Missense changes appear only in the conserved domains and are associated with a milder phenotype.

Dysphagia, melanosis, gastrointestinal stromal tumors and a germinal mutation of the KIT gene in an Argentine family.

Gastrointestinal stromal tumors (GIST) are the most common mesenchymatous neoplasms of the human digestive tract. They locate preferentially in stomach, duodenum or small bowel. Usually sporadic, familial cases unrelated to neurofibromatosis may be due to germline mutations in KIT or PDGFRA. We describe the first Argentine family with GIST in which we found, diffuse cutaneous melanosis, lentiginosis, and dysphagia. Dysphagia was not observed in the four families previously described with the same mutation. Histopathology resulted consistent with GIST, and tumor immunohistochemistry was likewise positive for DOG-1, CD117 (KIT) and CD34. The search for germline mutations identified the KIT c.1697T > C (p.559V > A) substitution in exon 11. Treatment with imatinib is furnishing positive results.

Dysphagia, melanosis, gastrointestinal stromal tumors and a germinal mutation of the KIT gene in an Argentine family / Dysphagia, melanosis, gastrointestinal stromal tumors and a germinal mutation of the KIT gene in an Argentine family.

Gastrointestinal stromal tumors (GIST) are the most common mesenchymatous neoplasms of the human digestive tract. They locate preferentially in stomach, duodenum or small bowel. Usually sporadic, familial cases unrelated to neurofibromatosis may be due to germline mutations in KIT or PDGFRA. We describe the first Argentine family with GIST in which we found, diffuse cutaneous melanosis, lentiginosis, and dysphagia. Dysphagia was not observed in the four families previously described with the same mutation. Histopathology resulted consistent with GIST, and tumor immunohistochemistry was likewise positive for DOG-1, CD117 (KIT) and CD34. The search for germline mutations identified the KIT c.1697T > C (p.559V > A) substitution in exon 11. Treatment with imatinib is furnishing positive results.

Aspectos Bioéticos y Legales de la Investigación Genética en Miembros Menores de Edad de una Familia con Adrenoleucodistrofia Ligada al X de Tucumán, Argentina / Bioethical and legal aspects of genetic research in underage memers of a familyy with x-linked adrenoleukodystrophy from tucumán, Arenntina / Aspecos bioéticoos e jurídicos da pesuisa genética em menores de idaade de uma família com adrenoleucodistrofia ligada ao cromossoma x (tucumán, Argentina)

El desarrollo de la Genética Humana ha puesto a disposición de la Medicina potentes recursos para Investigar los cambios en el material genético subyacentes a diversas enfermedades en pacientes individuales y sus familias. Semejante capacidad diagnóstica suele exceder en mucho a la capacidad de brindar una terapéutica específica, por lo que su utilidad médica reside en el perfeccionamiento del diagnóstico, la estimación del pronóstico clínico, y el cálculo del riesgo de recurrencia para futuros hermanos e hijos de un paciente dado; el paciente y/o su familia, por su parte, suelen buscar en el diagnóstico genético una certeza que les permita limitar su ansiedad. En Pediatría, el consenso mayoritario es que en los niños se justifica la investigación genética diagnóstica, que la investigación predictiva puede hacerse si la afección investigada permite una intervención médicamente beneficiosa durante la niñez, y que la del estado de portación debe diferirse hasta que el paciente alcance un cierto grado de madurez y competencia. El propósito de este trabajo es plantear los aspectos bioéticos y legales relacionados con la investigación de una familia que está segregando una mutación para adrenoleucodistrofia ligada al X, en la que por diversas circunstancias se estudió a menores de edad. Se discute la naturaleza de la enfermedad, el hecho de que tres de los individuos estudiados eran menores de edad, el rol proactivo de los padres en el proceso de toma de decisiones conducente a la investigación de tales miembros, y la existencia de un marco legal específico para la intervención.

Human Genetics development has furnished Medicine with potent resources to investigate changes in genetic material underneath a host of diseases in individual patients and their families. Such a diagnostic capability usually exceeds greatly the capability of specific therapeutic intervention, so its medical usefulness lies in perfecting the diagnosis, estimating the clinical prognosis and calculating the risk of recurrence among future sibs and children of a certain patient; on the other hand, the patient and/or his/her family usually look into genetic diagnosis for a certainty that enables them to limit their anxiety. In Pediatrics, the majority consensus is that children may be submitted to genetic research with diagnostic purposes, that predictive research might be done if the disease in question is amenable of a medically beneficial intervention during childhood, and that carrier state determination should be deferred until the patient reaches maturity and competence. The goal of this work is to review bioethical and legal aspects of the genetic investigation of a Tucumanian family segregating a mutation for X-linked adrenoleukodystrophy, in which for various reasons underage individuals were studied. We discuss the nature of the disease, the fact that three of the research subjects were underage, the proactive role of the family in the decision-making process leading to research those members, and the local existence of a specific legal frame for this intervention.

O desenvolvimento da genética humana tem dotado de recursos poderosos à medicina para pesquisar mudanças no material genético, subjacentes a diversas doenças nos pacientes e nas famílias. Essa capacidade de diagnóstico é muitas vezes maior do que a capacidade de fornecer uma terapia específica; portanto, sua utilidade médica está no aperfeiçoamento do diagnóstico, a estimativa do prognóstico clínico e o cálculo do risco de recorrência para irmãos e filhos de determinado paciente. O paciente e sua família tendem a visar no diagnóstico uma segurança genética que lhes permita limitar sua ansiedade. Em Pediatria, o consenso da maioria justifica a pesquisa genética diagnóstica em crianças, assinala que a pesquisa preditiva pode levar-se a cabo se a condição permite uma intervenção medicamente benéfica durante a infância e afirma que la solução ao estado de portador deverá pospor-se até que o paciente atinge determinada maturidade e competência. O objetivo deste trabalho é apresentar aspectos bioéticos e jurídicos relacionados com a pesquisa em de uma família que está segregando uma mutação para adrenoleucodistrofia ligada ao cromossoma X, na que por diversas razões foram estudados menores.Discute-se a natureza da doença, o fato que três dos indivíduos foram menores, o papel proativo dos pais no processo decisório -em quanto à pesquisa desses membros- e a existência de um quadro jurídico específico para a intervenção.

Procedimiento de detección molecular del polimorfismo C677T en el gen de la metilentetrahidrofolato reductasa (MTFHR) / Molecular detection procedure of the C677T polymorphism in the gen of the methylenetetrahydrofolate reductase (MTHFR)

La hiperhomocisteinemia es uno de los factores asociados a enfermedad vascular. Las causas genéticas son muy poco frecuentes, excepto la relacionada con termolabilidad de la metilentetrahidrofolato reductasa (MTHFR), rasgo de herencia autosómica recesiva. La variante molecular responsable es la sustitución C677T (Ala®Val) en el gen que codifica la MTHFR; la misma crea un sitio de restricción Hinf I, lo que posibilita su detección mediante digestión de ADN amplificado. La homocigosis para este alelo en un contexto de ácido fólico relativamente bajo se correlaciona con hiperhomocisteinemia moderada, y ésta sobre todo con arteriopatía periférica oclusiva. Nos propusimos poner a punto una técnica molecular para detectar esta sustitución. Para ello se extrajo ADN de gotas de sangre recogidas en una matriz especial; alícuotas de las suspensiones obtenidas calentando la matriz en agua fueron amplificadas enzimáticamente, y el producto digerido con Hinf I. Los fragmentos resultantes fueron analizados mediante electroforesis en geles de agarosa y tinción con bromuro de etidio. La técnica permite distinguir los genotipos homocigota dominante, homocigota recesivo y heterocigota para la sustitución investigada. Disponer de esta tecnología nos permitirá evaluar la relevancia patogénica de este polimorfismo en la población local, como paso previo a la oferta del servicio diagnóstico.