RESUMEN
BACKGROUND: The vast majority of BRCA1 missense sequence variants remain uncharacterized for their possible effect on protein expression and function, and therefore are unclassified in terms of their pathogenicity. BRCA1 plays diverse cellular roles and it is unlikely that any single functional assay will accurately reflect the total cellular implications of missense mutations in this gene. OBJECTIVE: To elucidate the effect of two BRCA1 variants, 5236G>C (G1706A) and 5242C>A (A1708E) on BRCA1 function, and to survey the relative usefulness of several assays to direct the characterisation of other unclassified variants in BRCA genes. METHODS AND RESULTS: Data from a range of bioinformatic, genetic, and histopathological analyses, and in vitro functional assays indicated that the 1708E variant was associated with the disruption of different cellular functions of BRCA1. In transient transfection experiments in T47D and 293T cells, the 1708E product was mislocalised to the cytoplasm and induced centrosome amplification in 293T cells. The 1708E variant also failed to transactivate transcription of reporter constructs in mammalian transcriptional transactivation assays. In contrast, the 1706A variant displayed a phenotype comparable to wildtype BRCA1 in these assays. Consistent with functional data, tumours from 1708E carriers showed typical BRCA1 pathology, while tumour material from 1706A carriers displayed few histopathological features associated with BRCA1 related tumours. CONCLUSIONS: A comprehensive range of genetic, bioinformatic, and functional analyses have been combined for the characterisation of BRCA1 unclassified sequence variants. Consistent with the functional analyses, the combined odds of causality calculated for the 1706A variant after multifactorial likelihood analysis (1:142) indicates a definitive classification of this variant as "benign". In contrast, functional assays of the 1708E variant indicate that it is pathogenic, possibly through subcellular mislocalisation. However, the combined odds of 262:1 in favour of causality of this variant does not meet the minimal ratio of 1000:1 for classification as pathogenic, and A1708E remains formally designated as unclassified. Our findings highlight the importance of comprehensive genetic information, together with detailed functional analysis for the definitive categorisation of unclassified sequence variants. This combination of analyses may have direct application to the characterisation of other unclassified variants in BRCA1 and BRCA2.
Asunto(s)
Proteína BRCA1/química , Proteína BRCA1/genética , Mutación Missense/genética , Adulto , Anciano , Australia , Neoplasias de la Mama/patología , Centrosoma/metabolismo , Femenino , Genes Reporteros/genética , Humanos , Pérdida de Heterocigocidad/genética , Persona de Mediana Edad , Modelos Moleculares , Procesamiento Proteico-Postraduccional , Transporte de Proteínas , Empalme del ARN/genética , Estabilidad del ARN/genética , Transcripción Genética , Activación Transcripcional/genéticaRESUMEN
A method is described of estimating the malaria incidence rate h and the recovery rate r from longitudinal data. The method is based on the assumption that the phenomenon of patent parasitaemia can be represented by a reversible two-state catalytic model; it is applicable to all problems that can be represented by such a model.The method was applied to data on falciparum malaria from the West African savanna and the findings suggested that immunity increases the rate of recovery from patent parasitaemia by a factor of up to 10, and also reduces the number of episodes of patent parasitaemia resulting from one inoculation. Under the effect of propoxur, h varies with the estimated man-biting rate of the vector while r increases, possibly owing to reduced super-infection.
Asunto(s)
Malaria/epidemiología , Adolescente , Adulto , Niño , Preescolar , Humanos , Lactante , Estudios Longitudinales , Nigeria , Plasmodium falciparum , Estaciones del AñoRESUMEN
The feasibility and effectiveness of a programme for the community control of rheumatic fever and rheumatic heart disease were studied in a cooperative multicentre project initiated and coordinated by the World Health Organization. The programme was carried out in seven centres in various developing countries of Africa, America, and Asia according to a common protocol, and is under way in a further eight countries in Latin America. Pilot community programmes were shown to be practicable and effective in reducing the burden of rheumatic heart disease in developing countries and their extension to cover entire populations should be encouraged.