OBJECTIVE: Degenerative intervertebral disc disease is common; however, the importance of genetic factors is unknown. This study sought to determine the extent of genetic influences on disc degeneration by classic twin study methods using magnetic resonance imaging (MRI). METHODS: We compared MRI features of degenerative disc disease in the cervical and lumbar spine of 172 monozygotic and 154 dizygotic twins (mean age 51.7 and 54.4, respectively) who were unselected for back pain or disc disease. An overall score for disc degeneration was calculated as the sum of the grades for disc height, bulge, osteophytosis, and signal intensity at each level. A "severe disease" score (excluding minor grades) and an "extent of disease" score (number of levels affected) were also calculated. RESULTS: For the overall score, heritability was 74% (95% confidence interval [95% CI] 64-81%) at the lumbar spine and 73% (95% CI 64-80%) at the cervical spine. For "severe disease," heritability was 64% and 79% at the lumbar and cervical spine, respectively, and for "extent of disease," heritability was 63% and 63%, respectively. These results were adjusted for age, weight, height, smoking, occupational manual work, and exercise. Examination of individual features revealed that disc height and bulge were highly heritable at both sites, and osteophytes were heritable in the lumbar spine. CONCLUSION: These results suggest an important genetic influence on variation in intervertebral disc degeneration. However, variation in disc signal is largely influenced by environmental factors shared by twins. The use of MRI scans to determine the phenotype in family and population studies should allow a better understanding of disease mechanisms and the identification of the genes involved.
OBJECTIVE:Degenerative intervertebral disc disease is common; however, the importance of genetic factors is unknown. This study sought to determine the extent of genetic influences on disc degeneration by classic twin study methods using magnetic resonance imaging (MRI). METHODS: We compared MRI features of degenerative disc disease in the cervical and lumbar spine of 172 monozygotic and 154 dizygotic twins (mean age 51.7 and 54.4, respectively) who were unselected for back pain or disc disease. An overall score for disc degeneration was calculated as the sum of the grades for disc height, bulge, osteophytosis, and signal intensity at each level. A "severe disease" score (excluding minor grades) and an "extent of disease" score (number of levels affected) were also calculated. RESULTS: For the overall score, heritability was 74% (95% confidence interval [95% CI] 64-81%) at the lumbar spine and 73% (95% CI 64-80%) at the cervical spine. For "severe disease," heritability was 64% and 79% at the lumbar and cervical spine, respectively, and for "extent of disease," heritability was 63% and 63%, respectively. These results were adjusted for age, weight, height, smoking, occupational manual work, and exercise. Examination of individual features revealed that disc height and bulge were highly heritable at both sites, and osteophytes were heritable in the lumbar spine. CONCLUSION: These results suggest an important genetic influence on variation in intervertebral disc degeneration. However, variation in disc signal is largely influenced by environmental factors shared by twins. The use of MRI scans to determine the phenotype in family and population studies should allow a better understanding of disease mechanisms and the identification of the genes involved.
Authors: You-Qiang Song; Tatsuki Karasugi; Kenneth M C Cheung; Kazuhiro Chiba; Daniel W H Ho; Atsushi Miyake; Patrick Y P Kao; Kit Ling Sze; Anita Yee; Atsushi Takahashi; Yoshiharu Kawaguchi; Yasuo Mikami; Morio Matsumoto; Daisuke Togawa; Masahiro Kanayama; Dongquan Shi; Jin Dai; Qing Jiang; Chengai Wu; Wei Tian; Na Wang; John C Y Leong; Keith D K Luk; Shea-ping Yip; Stacey S Cherny; Junwen Wang; Stefan Mundlos; Anthi Kelempisioti; Pasi J Eskola; Minna Männikkö; Pirkka Mäkelä; Jaro Karppinen; Marjo-Riitta Järvelin; Paul F O'Reilly; Michiaki Kubo; Tomoatsu Kimura; Toshikazu Kubo; Yoshiaki Toyama; Hiroshi Mizuta; Kathryn S E Cheah; Tatsuhiko Tsunoda; Pak-Chung Sham; Shiro Ikegawa; Danny Chan Journal: J Clin Invest Date: 2013-11 Impact factor: 14.808
Authors: Jillian E Mayer; James C Iatridis; Danny Chan; Sheeraz A Qureshi; Omri Gottesman; Andrew C Hecht Journal: Spine J Date: 2013-03 Impact factor: 4.166