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Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bardet-Biedl Syndrome (BBS) is a gentic disorder with primary features of retinal dystrophy, obesity, polydactyly, structural and functional renal abnormalities, and learning disabilities. In addition to displaying remarkable pleiotropy, BBS is a heterogeneous disorder with linkage to at least eight loci. The identification of the first five BBS genes provided little insight into BBS protein function. Ansley at al. have now identified a sixth BBS gene (BBS8) and provide evidence that the BBS8 protein and other BBS proteins localize to the basal body of ciliated cells, suggesting that BBS is a ciliary dysfunction disorder.
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PMID:Establishing a connection between cilia and Bardet-Biedl Syndrome. 1510 4

BBS4 is one of several proteins that cause Bardet-Biedl syndrome (BBS), a multisystemic disorder of genetic and clinical complexity. Here we show that BBS4 localizes to the centriolar satellites of centrosomes and basal bodies of primary cilia, where it functions as an adaptor of the p150(glued) subunit of the dynein transport machinery to recruit PCM1 (pericentriolar material 1 protein) and its associated cargo to the satellites. Silencing of BBS4 induces PCM1 mislocalization and concomitant deanchoring of centrosomal microtubules, arrest in cell division and apoptotic cell death. Expression of two truncated forms of BBS4 that are similar to those found in some individuals with BBS had a similar effect on PCM1 and microtubules. Our findings indicate that defective targeting or anchoring of pericentriolar proteins and microtubule disorganization contribute to the BBS phenotype and provide new insights into possible causes of familial obesity, diabetes and retinal degeneration.
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PMID:The Bardet-Biedl protein BBS4 targets cargo to the pericentriolar region and is required for microtubule anchoring and cell cycle progression. 1510 55

Bardet-Biedl syndrome (BBS) is a pleiotropic genetic disorder with the cardinal features of obesity, photoreceptor degeneration, polydactyly, hypogenitalism, renal abnormalities, and developmental delay. Other associated clinical findings in BBS patients include diabetes, hypertension, and congenital heart defects. The clinical diagnosis is based on the presence of at least four of the cardinal symptoms. BBS is recognized to be a genetically heterogeneous autosomal recessive disorder mapping to eight known loci. Positional cloning and candidate gene evaluation have resulted in the identification of six BBS genes. Mutation of one of these genes, BBS6, also causes McKusick-Kaufman syndrome. The BBS6 gene is predicted to code for a protein with sequence similarity to the chaperonin family of proteins. The predicted BBS1, BBS2, BBS4, BBS7, and BBS8 gene products do not seem to be molecular chaperones, on the basis of a lack of sequence similarity to the chaperonin family of proteins. The identification of BBS8 suggests a possible role in cilia function for BBS gene products. It remains to be determined whether the multiple BBS proteins are part of a multisubunit complex or do not directly interact with each other but are part of a common pathway. The study of BBS illustrates the value of using isolated inbred populations for the study of human genetic diseases and suggests strategies for facilitating the study of complex diseases and traits.
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PMID:Use of isolated populations in the study of a human obesity syndrome, the Bardet-Biedl syndrome. 1515 61

The functions of the proteins encoded by the Bardet-Biedl syndrome (BBS) genes are unknown. Mutations in these genes lead to the pleiotropic human disorder BBS, which is characterized by obesity, retinopathy, polydactyly, renal and cardiac malformations, learning disabilities, and hypogenitalism. Secondary features include diabetes mellitus and hypertension. Recently, it has been suggested that the BBS phenotypes are the result of a lack of cilia formation or function. In this study, we show that mice lacking the Bbs4 protein have major components of the human phenotype, including obesity and retinal degeneration. We show that Bbs4-null mice develop both motile and primary cilia, demonstrating that Bbs4 is not required for global cilia formation. Interestingly, male Bbs4-null mice do not form spermatozoa flagella, and BBS4 retinopathy involves apoptotic death of photoreceptors, the primary ciliated cells of the retina. These mutation data demonstrate a connection between the function of a BBS protein and cilia. To further evaluate an association between cilia and BBS, we performed homology comparisons of BBS proteins in model organisms and find that BBS proteins are specifically conserved in ciliated organisms.
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PMID:Bardet-Biedl syndrome type 4 (BBS4)-null mice implicate Bbs4 in flagella formation but not global cilia assembly. 1517 97

The increasing identification of disease genes is revealing a growing number of traits that fail to conform to traditional Mendelian paradigms, thereby creating new challenges to both genetic investigators and clinicians. Bardet-Biedl syndrome (BBS) is one such disorder that has helped to define 'oligogenic' inheritance, a term that implies that some diseases are not inherited as simple single-gene Mendelian disorders and yet are not classic complex traits, but rather fit a model in which mutations in a small number of genes may interact genetically to manifest the phenotype. BBS is a pleiotropic disorder characterized by postnatal obesity, post-axial polydactyly, and progressive retinal dystrophy. Eight BBS loci have been identified to date and six of these genes have been cloned. Mutation analysis of these BBS genes in a cohort of patients has led to the description of the novel phenomenon of 'triallelic inheritance', wherein families were identified in which three mutations from genes at two different BBS loci segregate with expression of the disease. Modeling the cooperative ability of alleles of different genes at distinct loci to give rise to a particular phenotype will facilitate the understanding of complex multifactorial and polygenic traits.
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PMID:Triallelic inheritance: a bridge between Mendelian and multifactorial traits. 1522 52

Bardet-Biedl syndrome (BBS) is a genetically heterogeneous developmental disorder whose molecular basis is largely unknown. Here, we show that mutations in the Caenorhabditis elegans bbs-7 and bbs-8 genes cause structural and functional defects in cilia. C. elegans BBS proteins localize predominantly at the base of cilia, and like proteins involved in intraflagellar transport (IFT), a process necessary for cilia biogenesis and maintenance, move bidirectionally along the ciliary axoneme. Importantly, we demonstrate that BBS-7 and BBS-8 are required for the normal localization/motility of the IFT proteins OSM-5/Polaris and CHE-11, and to a notably lesser extent, CHE-2. We propose that BBS proteins play important, selective roles in the assembly and/or function of IFT particle components. Our findings also suggest that some of the cardinal and secondary symptoms of BBS, such as obesity, diabetes, cardiomyopathy, and learning defects may result from cilia dysfunction.
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PMID:Loss of C. elegans BBS-7 and BBS-8 protein function results in cilia defects and compromised intraflagellar transport. 1523 40

Bardet-Biedl syndrome (BBS) is a genetically heterogeneous, pleiotropic human disorder characterized by obesity, retinopathy, polydactyly, renal and cardiac malformations, learning disabilities, and hypogenitalism. Eight BBS loci have been mapped, and seven genes have been identified. BBS3 was previously mapped to chromosome 3 by linkage analysis in a large Israeli Bedouin kindred. The rarity of other families mapping to the BBS3 locus has made it difficult to narrow the disease interval sufficiently to identify the gene by positional cloning. We hypothesized that the genomes of model organisms that contained the orthologues to known BBS genes would also likely contain a BBS3 orthologue. Therefore, comparative genomic analysis was performed to prioritize BBS candidate genes for mutation screening. Known BBS proteins were compared with the translated genomes of model organisms to identify a subset of organisms in which these proteins were conserved. By including multiple organisms that have relatively small genome sizes in the analysis, the number of candidate genes was reduced, and a few genes mapping to the BBS3 interval emerged as the best candidates for this disorder. One of these genes, ADP-ribosylation factor-like 6 (ARL6), contains a homozygous stop mutation that segregates completely with the disease in the Bedouin kindred originally used to map the BBS3 locus, identifying this gene as the BBS3 gene. These data illustrate the power of comparative genomic analysis for the study of human disease and identifies a novel BBS gene.
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PMID:Comparative genomic analysis identifies an ADP-ribosylation factor-like gene as the cause of Bardet-Biedl syndrome (BBS3). 1525 60

Bardet-Biedl syndrome (BBS) is an autosomal recessive condition with a wide spectrum of clinical features. The principal manifestations are rod-cone dystrophy (sometimes called atypical retinitis pigmentosa), postaxial polydactyly, central obesity, mental retardation, hypogonadism, and renal dysfunction. The clinical diagnosis of syndrome X defines a patient with abnormal glucose metabolism, hypertension, hyperlipidemia and obesity. We report here a 15 year-old girl with BBS presenting with syndrome X.
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PMID:Bardet-Biedl syndrome with syndrome X: a patient report. 1527 Apr 11

RAB, ADP-ribosylation factors (ARFs) and ARF-like (ARL) proteins belong to the Ras superfamily of small GTP-binding proteins and are essential for various membrane-associated intracellular trafficking processes. None of the approximately 50 known members of this family are linked to human disease. Using a bioinformatic screen for ciliary genes in combination with mutational analyses, we identified ARL6 as the gene underlying Bardet-Biedl syndrome type 3, a multisystemic disorder characterized by obesity, blindness, polydactyly, renal abnormalities and cognitive impairment. We uncovered four different homozygous substitutions in ARL6 in four unrelated families affected with Bardet-Biedl syndrome, two of which disrupt a threonine residue important for GTP binding and function of several related small GTP-binding proteins. Analysis of the Caenorhabditis elegans ARL6 homolog indicates that it is specifically expressed in ciliated cells, and that, in addition to the postulated cytoplasmic functions of ARL proteins, it undergoes intraflagellar transport. These findings implicate a small GTP-binding protein in ciliary transport and the pathogenesis of a pleiotropic disorder.
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PMID:Mutations in a member of the Ras superfamily of small GTP-binding proteins causes Bardet-Biedl syndrome. 1531 42

Defects in cilia are associated with several human disorders, including Kartagener syndrome, polycystic kidney disease, nephronophthisis and hydrocephalus. We proposed that the pleiotropic phenotype of Bardet-Biedl syndrome (BBS), which encompasses retinal degeneration, truncal obesity, renal and limb malformations and developmental delay, is due to dysfunction of basal bodies and cilia. Here we show that individuals with BBS have partial or complete anosmia. To test whether this phenotype is caused by ciliary defects of olfactory sensory neurons, we examined mice with deletions of Bbs1 or Bbs4. Loss of function of either BBS protein affected the olfactory, but not the respiratory, epithelium, causing severe reduction of the ciliated border, disorganization of the dendritic microtubule network and trapping of olfactory ciliary proteins in dendrites and cell bodies. Our data indicate that BBS proteins have a role in the microtubule organization of mammalian ciliated cells and that anosmia might be a useful determinant of other pleiotropic disorders with a suspected ciliary involvement.
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PMID:Loss of BBS proteins causes anosmia in humans and defects in olfactory cilia structure and function in the mouse. 1532 45


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