Publications by authors named "Andrea Alter"

Leprosy is caused by infection with Mycobacterium leprae and is classified clinically into paucibacillary (PB) or multibacillary (MB) subtypes based on the number of skin lesions and the bacillary index detected in skin smears. We previously identified a major PB susceptibility locus on chromosome region 10p13 in Vietnamese families by linkage analysis. In the current study, we conducted high-density association mapping of the 9.

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One of the persistent challenges of genetic association studies is the replication of genetic marker-disease associations across ethnic groups. Here, we conducted high-density association mapping of PARK2/PACRG SNPs with leprosy and identified 69 SNPs significantly associated with leprosy in 198 single-case Vietnamese leprosy families. A total of 56 associated SNPs localized to the overlapping promoter regions of PARK2/PACRG.

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Article Synopsis
  • A genomewide association study identified 16 SNPs linked to leprosy in Chinese patients, with 4 of these related to Crohn's disease pathways.
  • Researchers then analyzed these SNPs in 474 Vietnamese families to see if they were also linked to leprosy.
  • The study confirmed that certain SNPs are factors for leprosy susceptibility in Vietnam, highlighting a genetic overlap between Crohn's disease and leprosy.
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Leprosy is an infectious disease caused by Mycobacterium leprae. Tumor necrosis factor (TNF) plays a key role in the host response. Some association studies have implicated the single nucleotide polymorphism TNF -308G>A in leprosy susceptibility, but these results are still controversial.

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Experimental evidence suggested the existence of unidentified leprosy susceptibility loci in the human leukocyte antigen (HLA) complex. To identify such genetic risk factors, a high-density association scan of a 1.9-mega-base (Mb) region in the HLA complex was performed.

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Leprosy (Hansen's disease) is a human infectious disease whose etiological agent, Mycobacterium leprae, was identified by G. H. A.

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Article Synopsis
  • The region 10p13, which contains the MRC1 gene linked to leprosy susceptibility, was studied in Vietnamese and Brazilian populations to evaluate the G396S SNP's role in the disease.
  • Significant associations were found indicating that certain variants of the G396S polymorphism are linked with higher chances of developing leprosy, especially multibacillary forms.
  • Despite the identified genetic associations, experiments showed that the mannose receptor did not effectively bind or internalize Mycobacterium leprae, suggesting another unidentified host molecule may influence this interaction.
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Fifty years ago, the first identification of a non Mendelian genetic contribution to the development of a common infectious disease, i.e. the association between malaria and sickle-cell trait, was shown using a supervised approach which tests a limited number of candidate genes selected by hypothesis.

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Leprosy (Hansen's disease) is a human infectious disease that can be effectively treated with long-term administration of multi-drug therapy. In 2006, over 250,000 new cases were reported to the World Health Organization. In the nineteenth century, disagreement among leprologists regarding the hereditary or infectious nature of leprosy was resolved with the identification of the etiological agent, Mycobacterium leprae.

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The Mitsuda reaction, a delayed granulomatous skin reaction elicited by the intradermal injection of heat-killed Mycobacterium leprae, is an in vivo test reflecting the ability to generate an immune granuloma after sensitization by diverse mycobacterial infections. Accumulating evidence for the genetic control of the Mitsuda reaction has been reported. We performed a genomewide linkage scan for the quantitative Mitsuda reaction in 19 large families from Vietnam with a history of leprosy (114 offspring).

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Host genetics has an important role in leprosy, and variants in the shared promoter region of PARK2 and PACRG were the first major susceptibility factors identified by positional cloning. Here we report the linkage disequilibrium mapping of the second linkage peak of our previous genome-wide scan, located close to the HLA complex. In both a Vietnamese familial sample and an Indian case-control sample, the low-producing lymphotoxin-alpha (LTA)+80 A allele was significantly associated with an increase in leprosy risk (P = 0.

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Genomic imprinting decreases the power of classical linkage analysis, in which paternal and maternal transmissions of marker alleles are equally weighted. Several methods have been proposed for taking genomic imprinting into account in the model-free linkage analysis of binary traits. However, none of these methods are suitable for the formal identification and quantification of genomic imprinting in the presence of linkage.

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The molecular basis of genetic predisposition to pulmonary tuberculosis in adults remains largely elusive. Few candidate genes have consistently been implicated in tuberculosis susceptibility, and no conclusive linkage was found in two previous genome-wide screens. We report here a genome-wide linkage study in a total sample of 96 Moroccan multiplex families, including 227 siblings with microbiologically and radiologically proven pulmonary tuberculosis.

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There is growing interest in the fundamental roles that B cells may play in regulating immune responses. Emerging animal studies point to an important contribution of B cell effector cytokines to immune modulation, yet little is known about the factors regulating such cytokine production. We report that the profile of human B cell cytokine production is context dependent, being critically influenced by the balance of signals through the B cell receptor and CD40.

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Leprosy is caused by Mycobacterium leprae and affects about 700,000 individuals each year. It has long been thought that leprosy has a strong genetic component, and recently we mapped a leprosy susceptibility locus to chromosome 6 region q25-q26 (ref. 3).

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Matrix metalloproteinases (MMPs) are implicated in multiple sclerosis where one of their roles may be to facilitate the transmigration of circulating leukocytes into the CNS. Studies have focused on only a few MMPs, and much remains unknown of which of the 23 MMP family members is/are critical to the multiple sclerosis disease process. Using quantitative real time polymerase chain reactions, we have systematically analysed the expression of all 23 MMP members in subsets of leukocytes isolated from the blood of normal individuals.

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Circulating B cells enter the CNS as part of normal immune surveillance and in pathologic states, including the common and disabling illness multiple sclerosis. However, little is known about the molecular mechanisms that mediate human B cell interaction with the specialized brain endothelial cells comprising the blood-brain barrier (BBB). We studied the molecular mechanisms that regulate the migration of normal human B cells purified ex vivo, across human adult brain-derived endothelial cells (HBECs).

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