Concordance of disease severity among family members with ankylosing spondylitis?

Brophy, S., Hickey, S., Menon, A., Taylor, G., Bradbury, L., Hamersma, J., Brown, M. A., & Calin, A. (2004) Concordance of disease severity among family members with ankylosing spondylitis? Journal of Rheumatology, 31(9), pp. 1775-1778.

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The heritability of disease activity and function in ankylosing spondylitis (AS) have been estimated at 0.51 and 0.63 (i.e., 51% and 63%), respectively. We examined the concordance of disease severity among family members in terms of disease activity, function, radiological change, prevalence of iritis, and juvenile onset.


Disease activity and functional impairment due to AS were studied using the Bath AS Disease Activity Index (BASDAI) and Functional Index (BASFI) self-administered questionnaires; radiographic involvement was measured using the Bath AS Radiology Index (BASRI) scale. Familial correlation of BASDAI and BASFI was assessed in 406 families with 2 or more cases, using the program PAP. Parent-child and sibling-sibling concordance for iritis and juvenile AS were also studied in these families. Heritability of radiological disease severity based on the BASRI was assessed in 29 families containing 60 affected individuals using the program SOLAR.


Correlations between parent-child pairs for disease activity and function were 0.07 for both. Correlations between sibling pairs for disease activity and function were 0.27 and 0.36, respectively. The children of AS parents with iritis were more likely to develop iritis [27/71 (38%)] than children of non-iritis AS parents [13/70 (19%)] (p = 0.01). Parents with JAS were more likely to have children with JAS [17/30 (57%) compared to non-JAS parents 34/111 (30%)] (p = 0.002). The heritability of radiological disease severity based on the BASRI was 0.62. Conclusion. While correlation in severity between parent and child is poor, siblings do resemble each other in terms of severity, supporting the findings of segregation studies indicating significant genetic dominance in the heritable component of disease activity. Significant parent-child concordance for iritis and juvenile disease onset suggest that there are genetic risk factors for these traits independent of those determining the risk of AS itself. The finding of significant heritability of radiological change (BASRI) provides support using an objective measure for the observed heritability of the questionnaire-assessed disease severity scores, ASDAI and BASFI.

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33 citations in Web of Science®
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ID Code: 89544
Item Type: Journal Article
Refereed: Yes
Additional Information: Cited By :28
Export Date: 21 September 2015
Correspondence Address: Brophy, S.; Swansea Clinical School, University of Wales Swansea, Singleton Park, Swansea, SA2 8PP, United Kingdom; email:
Keywords: Ankylosing spondylitis, Inheritance, Severity, article, controlled study, correlation analysis, disease activity, disease severity, family, female, functional disease, genetic analysis, genetic risk, human, iritis, major clinical study, male, onset age, priority journal, questionnaire, Adult, Child, Family Health, Humans, Parents, Phenotype, Prevalence, Prognosis, Risk Factors, Severity of Illness Index, Siblings, Spondylitis, Ankylosing
ISSN: 0315-162X
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Copyright Owner: Copyright © 2004 by The Journal of Rheumatology
Deposited On: 27 Oct 2015 01:16
Last Modified: 26 Jun 2017 03:01

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