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Conference Paper: Comprehensive Analysis of MRI-Phenotypes Provides New Insights into Lumbar Disc Degeneration for Genetic Studies

TitleComprehensive Analysis of MRI-Phenotypes Provides New Insights into Lumbar Disc Degeneration for Genetic Studies
Authors
Issue Date2014
PublisherGeorg Thieme Verlag. The Journal's web site is located at http://www.thieme.com/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=1351&category_id=90&option=com_virtuemart&Itemid=53
Citation
World Forum for Spine Research (WFSR), Xi'an, China,15-17 May 2014. In Global Spine Journal, 2014, v. 4 n. Suppl. 1, p. S20-S21, abstract no. ST5.06 How to Cite?
AbstractIntroduction For the past two decades, numerous genetic association studies addressing lumbar disc degeneration (LDD) have been performed, but few of them can be replicated. The possible reasons could be the phenotype definition of LDD was highly variable between studies and level-specific variations were not addressed. As such, this study addressed the relationship between MRI features of the discs at different lumbar levels to explore the etiology of LDD; thereby, providing new insights and measurements for genetic studies. Materials and Methods Sagittal T2-weighted MRI of the lumbar spine was assessed in a population sample of 2,952 Southern Chinese (mean age, 41.1 years; range, 15.0-65.4 years; 40.7% males; 59.3% females). Loss of disc signal intensity, disc bulges/extrusions, Schmorl nodes, high-intensity zones, and bone marrow changes were assessed on imaging. Subject demographics, environmental, and lifestyle factors were also evaluated. Pairwised polychoric correlations between phenotypes in all five lumbar discs were performed using R v3.01 Heritability was estimated by Genome-wide Complex Trait Analysis (GCTA) using genotype data to identify phenotypes shared common genetic factors. Local regressions were performed between conditions and risk factors, such as age and body mass index, to distinguish the relationship between phenotypes and environmental factors. Phenotypes which were highly correlated and shared common genetic factors were grouped to form a new measurement. Results Analyses suggested distinct genetic etiologies for the upper (L1-L2) versus lower regions (L3-S1).Estimation of heritability showed the upper (L1-L2) and lower regions (L3-S1) of the lumbar spine shared common genetics factors, respectively; but upper and lower regions could present independent genetic features. Regression between phenotype and age denoted that age-related condition was restricted to lower regions while the upper region suggests developmental characters. By combining highly correlated MRI phenotypes in the upper and lower regions separately, two composite scores were generated: a degenerative score (DgS) (represents agerelated disc changes) and a developmental score (DvS) (represents congenital variations). Conclusion Based on one of the largest population-based MRI studies of LDD, comprehensive analyses of MRI phenotypes provided new insights into its etiology. Our study proposes a novel phenotype scoring system to assess disc changes on MRI. This scoring system can be used as the basis to promote a standardization of phenotype delineation, maximizing the potential of replication and meta-analysis studies of genetic risk factors for LDD. Disclosure of Interest None declared
DescriptionConference theme: The Intervertebral Disc - from Degeneration to Therapeutic Motion Preservation
Short Talk Session
The abstract can be viewed at http://www.spineresearchforum.org/WFSR_2014_Thieme_AbstractBook_with_Cover.pdf
Persistent Identifierhttp://hdl.handle.net/10722/203765
ISSN
2015 SCImago Journal Rankings: 0.108

 

DC FieldValueLanguage
dc.contributor.authorLi, Yen_US
dc.contributor.authorSamartzis, Den_US
dc.contributor.authorCampbell, Den_US
dc.contributor.authorCheung, KMCen_US
dc.contributor.authorLuk, KDKen_US
dc.contributor.authorKarppinen, JIen_US
dc.contributor.authorCheah, KSEen_US
dc.contributor.authorChan, Den_US
dc.contributor.authorSham, PCen_US
dc.date.accessioned2014-09-19T16:40:58Z-
dc.date.available2014-09-19T16:40:58Z-
dc.date.issued2014en_US
dc.identifier.citationWorld Forum for Spine Research (WFSR), Xi'an, China,15-17 May 2014. In Global Spine Journal, 2014, v. 4 n. Suppl. 1, p. S20-S21, abstract no. ST5.06en_US
dc.identifier.issn2192-5682-
dc.identifier.urihttp://hdl.handle.net/10722/203765-
dc.descriptionConference theme: The Intervertebral Disc - from Degeneration to Therapeutic Motion Preservation-
dc.descriptionShort Talk Session-
dc.descriptionThe abstract can be viewed at http://www.spineresearchforum.org/WFSR_2014_Thieme_AbstractBook_with_Cover.pdf-
dc.description.abstractIntroduction For the past two decades, numerous genetic association studies addressing lumbar disc degeneration (LDD) have been performed, but few of them can be replicated. The possible reasons could be the phenotype definition of LDD was highly variable between studies and level-specific variations were not addressed. As such, this study addressed the relationship between MRI features of the discs at different lumbar levels to explore the etiology of LDD; thereby, providing new insights and measurements for genetic studies. Materials and Methods Sagittal T2-weighted MRI of the lumbar spine was assessed in a population sample of 2,952 Southern Chinese (mean age, 41.1 years; range, 15.0-65.4 years; 40.7% males; 59.3% females). Loss of disc signal intensity, disc bulges/extrusions, Schmorl nodes, high-intensity zones, and bone marrow changes were assessed on imaging. Subject demographics, environmental, and lifestyle factors were also evaluated. Pairwised polychoric correlations between phenotypes in all five lumbar discs were performed using R v3.01 Heritability was estimated by Genome-wide Complex Trait Analysis (GCTA) using genotype data to identify phenotypes shared common genetic factors. Local regressions were performed between conditions and risk factors, such as age and body mass index, to distinguish the relationship between phenotypes and environmental factors. Phenotypes which were highly correlated and shared common genetic factors were grouped to form a new measurement. Results Analyses suggested distinct genetic etiologies for the upper (L1-L2) versus lower regions (L3-S1).Estimation of heritability showed the upper (L1-L2) and lower regions (L3-S1) of the lumbar spine shared common genetics factors, respectively; but upper and lower regions could present independent genetic features. Regression between phenotype and age denoted that age-related condition was restricted to lower regions while the upper region suggests developmental characters. By combining highly correlated MRI phenotypes in the upper and lower regions separately, two composite scores were generated: a degenerative score (DgS) (represents agerelated disc changes) and a developmental score (DvS) (represents congenital variations). Conclusion Based on one of the largest population-based MRI studies of LDD, comprehensive analyses of MRI phenotypes provided new insights into its etiology. Our study proposes a novel phenotype scoring system to assess disc changes on MRI. This scoring system can be used as the basis to promote a standardization of phenotype delineation, maximizing the potential of replication and meta-analysis studies of genetic risk factors for LDD. Disclosure of Interest None declared-
dc.languageengen_US
dc.publisherGeorg Thieme Verlag. The Journal's web site is located at http://www.thieme.com/index.php?page=shop.product_details&flypage=flypage.tpl&product_id=1351&category_id=90&option=com_virtuemart&Itemid=53-
dc.relation.ispartofGlobal Spine Journalen_US
dc.rightsGlobal Spine Journal. Copyright © Georg Thieme Verlag.-
dc.titleComprehensive Analysis of MRI-Phenotypes Provides New Insights into Lumbar Disc Degeneration for Genetic Studiesen_US
dc.typeConference_Paperen_US
dc.identifier.emailSamartzis, D: dspine@hku.hken_US
dc.identifier.emailCheung, KMC: cheungmc@hku.hken_US
dc.identifier.emailLuk, KDK: hrmoldk@hkucc.hku.hken_US
dc.identifier.emailCheah, KSE: hrmbdkc@hku.hken_US
dc.identifier.emailChan, D: chand@hku.hken_US
dc.identifier.emailSham, PC: pcsham@hku.hken_US
dc.identifier.authoritySamartzis, D=rp01430en_US
dc.identifier.authorityCheung, KMC=rp00387en_US
dc.identifier.authorityLuk, KDK=rp00333en_US
dc.identifier.authorityCheah, KSE=rp00342en_US
dc.identifier.authorityChan, D=rp00540en_US
dc.identifier.hkuros238036en_US
dc.identifier.volume4-
dc.identifier.issueSuppl. 1-
dc.identifier.spageS20, abstract no. ST5.06-
dc.identifier.epageS21, abstract no. ST5.06-
dc.publisher.placeGermanyen_US

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