RESUMO
Inclusion body myopathy associated with Paget disease of bone and frontotemporal dementia (IBMPFD, OMIM 167320) has recently been attributed to eight missense mutations in valosin-containing protein (VCP). We report novel VCP mutations N387H and L198W in six individuals from two families who presented with proximal muscle weakness at a mean age of diagnosis of 40 years, most losing the ability to walk within a few years of onset. Electromyographic studies in four individuals were suggestive of 'myopathic' changes, and neuropathic pattern was identified in one individual in family 1. Muscle biopsy in four individuals showed myopathic changes characterized by variable fiber size, two individuals showing rimmed vacuoles and IBM-type cytoplasmic inclusions in muscle fibers, and electron microscopy in one individual revealing abundant intranuclear inclusions. Frontotemporal dementia associated with characteristic behavioral changes including short-term memory loss, language difficulty, and antisocial behavior was observed in three individuals at a mean age of 47 years. Detailed brain pathology in one individual showed cortical degenerative changes, most severe in the temporal lobe and hippocampus. Abundant ubiquitin-positive tau-, alpha-synuclein-, polyglutamine repeat-negative neuronal intranuclear inclusions and only rare intracytoplasmic VCP positive inclusions were seen. These new mutations may cause structural changes in VCP and provide some insight into the functional effects of pathogenic mutations.
Assuntos
Adenosina Trifosfatases/genética , Proteínas de Ciclo Celular/genética , Demência/complicações , Demência/genética , Miosite de Corpos de Inclusão/complicações , Miosite de Corpos de Inclusão/genética , Osteíte Deformante/complicações , Osteíte Deformante/genética , Adulto , Análise Mutacional de DNA , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos Moleculares , Mutação , Linhagem , Proteína com ValosinaRESUMO
Bacterial vectors containing large inserts of genomic DNA are now the standard substrates for large-scale genomic sequencing. Long overlaps between some clones lead to considerable redundant effort. A method for deleting defined regions from bacterial artificial chromosome (BAC) inserts, using homologous recombination, was applied to minimize the overlap between successive BAC clones. This procedure, called trimming, was carried out in the recA(-) BAC host. We have precisely deleted up to 70 kb of DNA from BACs that were to be sequenced. This method requires minimal prior characterization of the clones: collections of BAC end sequences or STS-based maps will accelerate the process. BAC trimming will be useful in both small and large genome sequencing projects and will be of particular utility for gap closure in finishing phases.