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This article presents the range of manifestations of tuberculosis (TB) of the craniospinal axis. Central nervous system (CNS) infection with Mycobacterium tuberculosis occurs either in a diffuse form as basal exudative leptomeningitis or in a localized form as tuberculoma, abscess, or cerebritis. In addition to an extensive review of computed tomography and magnetic resonance features, the pathogenesis and the relevant clinical setting are discussed. Modern imaging is a cornerstone in the early diagnosis of CNS tuberculosis and may prevent unnecessary morbidity and mortality. Contrast-enhanced MR imaging is generally considered as the modality of choice in the detection and assessment of CNS tuberculosis.

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This study illustrates that Plekhm1 is an essential protein for bone resorption, as loss-of-function mutations were found to underlie the osteopetrotic phenotype of the incisors absent rat as well as an intermediate type of human osteopetrosis. Electron and confocal microscopic analysis demonstrated that monocytes from a patient homozygous for the mutation differentiated into osteoclasts normally, but when cultured on dentine discs, the osteoclasts failed to form ruffled borders and showed little evidence of bone resorption. The presence of both RUN and pleckstrin homology domains suggests that Plekhm1 may be linked to small GTPase signaling. We found that Plekhm1 colocalized with Rab7 to late endosomal/lysosomal vesicles in HEK293 and osteoclast-like cells, an effect that was dependent on the prenylation of Rab7. In conclusion, we believe PLEKHM1 to be a novel gene implicated in the development of osteopetrosis, with a putative critical function in vesicular transport in the osteoclast.

The purpose of this article is to review the imaging characteristics of musculoskeletal tuberculosis. Skeletal tuberculosis represents one-third of all cases of tuberculosis occurring in extrapulmonary sites. Hematogenous spread from a distant focus elsewhere in the body is the cornerstone in the understanding of imaging features of musculoskeletal tuberculosis. The most common presentations are tuberculous spondylitis, arthritis, osteomyelitis, and soft tissue involvement. The diagnostic value of the different imaging techniques, which include conventional radiography, CT, and MR imaging, are emphasized. Whereas conventional radiography is the mainstay in the diagnosis of tuberculous arthritis and osteomyelitis, MR imaging may detect associated bone marrow and soft tissue abnormalities. MR imaging is generally accepted as the imaging modality of choice for diagnosis, demonstration of the extent of the disease of tuberculous spondylitis, and soft tissue tuberculosis. Moreover, it may be very helpful in the differential diagnosis with pyogenic spondylodiscitis, as it may easily demonstrate anterior corner destruction, the relative preservation of the intervertebral disk, multilevel involvement with or without skip lesions, and a large soft tissue abscess, as these are all arguments in favor of a tuberculous spondylitis. On the other hand, CT is still superior in the demonstration of calcifications, which are found in chronic tuberculous abscesses.

Camurati-Engelmann disease (CED; MIM 131300), or progressive diaphyseal dysplasia, is a rare, sclerosing bone dysplasia inherited in an autosomal dominant manner. Recently, the gene causing CED has been assigned to the chromosomal region 19q13 (refs 1-3). Because this region contains the gene encoding transforming growth factor-beta 1 (TGFB1), an important mediator of bone remodelling, we evaluated TGFB1 as a candidate gene for causing CED.

Hereditary multiple exostoses (EXT; MIM 133700) is an autosomal dominant bone disorder characterized by the presence of multiple benign cartilage-capped tumors (exostoses). Besides suffering complications caused by the pressure of these exostoses on the surrounding tissues, EXT patients are at an increased risk for malignant chondrosarcoma, which may develop from an exostosis. EXT is genetically heterogeneous, and three loci have been identified so far: EXT1, on chromosome 8q23-q24; EXT2, on 11p11-p12; and EXT3, on the short arm of chromosome 19. The EXT1 and EXT2 genes were cloned recently, and they were shown to be homologous. We have now analyzed the EXT1 and EXT2 genes, in 26 EXT families originating from nine countries, to identify the underlying disease-causing mutation. Of the 26 families, 10 families had an EXT1 mutation, and 10 had an EXT2 mutation. Twelve of these mutations have never been described before. In addition, we have reviewed all EXT1 and EXT2 mutations reported so far, to determine the nature, frequency, and distribution of mutations that cause EXT. From this analysis, we conclude that mutations in either the EXT1 or the EXT2 gene are responsible for the majority of EXT cases. Most of the mutations in EXT1 and EXT2 cause premature termination of the EXT proteins, whereas missense mutations are rare. The development is thus mainly due to loss of function of the EXT genes, consistent with the hypothesis that the EXT genes have a tumor- suppressor function.

Tuberculosis, more than any other infectious disease, has always been a challenge, since it has been responsible for a great amount of morbidity and mortality in humans. After a steady decline in the number of new cases during the twentieth century, due to improved social and environmental conditions, early diagnosis, and the development of antituberculous medication, a stagnation and even an increase in the number of new cases was noted in the mid-1980s. The epidemiological alteration is multifactorial: global increase in developing countries; minority groups (HIV and other immunocompromised patients); and elderly patients due to an altered immune status. Other factors that may be responsible are a delayed diagnosis, especially in elderly patients, incomplete or inadequate therapy, and the emergence of multidrug-resistant tuberculosis. The course of the disease and its corresponding clinicoradiological pattern depends on the interaction between the organism and the host response. Classically, pulmonary tuberculosis has been classified in primary tuberculosis, which occurred previously in children, and postprimary tuberculosis, occurring in adult patients. In industrialized countries, however, there seems to be a shift of primary tuberculosis towards adults. Furthermore, due to an altered immunological response in certain groups, such as immunocompromised and elderly patients, an atypical radioclinical pattern may occur. The changing landscape, in which tuberculosis occurs, as well as the global resurgence, and the changed spectrum of the clinical and radiological presentation, justify a renewed interest of radiologists for the imaging features of pulmonary tuberculosis. This article deals with the usual imaging features of pulmonary tuberculosis as well as the atypical patterns encountered in immunodepressed and elderly patients.