Recurrence risk of ankylosing spondylitis in different degrees of probands of affected subjects
| Study | Relationship | MZ twins | Siblings | Parent-child | First degree | Second degree | Third degree |
| de Blécourt18 | Number affected | — | 24 | 5 | 29 | 8 | 7 |
| Number studied | — | 401 | 191 | 592 | 834 | 997 | |
| Recurrence risk (%) | — | 6.0 | 2.6 | 4.9 | 1.0 | 0.7 | |
| Brown5 | Number affected | 6 | 4 | — | 4 | — | — |
| Number studied | 8 | 32 | — | 32 | — | — | |
| Recurrence risk (%) | 75 | 12.5 | — | 12.5 | — | — | |
| Calin11 | Number affected | — | 363 | 32 | 363 | — | — |
| Number studied | — | 4298 | 275 | 4298 | — | — | |
| Recurrence risk (%) | — | 8.4 | 11.6 | 8.4 | — | — | |
| Carter19 | Number affected | — | 10 | — | 10 | — | — |
| Number studied | — | 169 | — | 169 | — | — | |
| Recurrence risk (%) | — | 5.9 | — | 5.9 | — | — | |
| Emery20 | Number affected | 1 | 0 | — | 0 | — | — |
| Number studied | 2 | 4 | — | 4 | — | — | |
| Recurrence risk (%) | 50 | 0 | — | 0 | — | — | |
| Jarvinen21 | Number affected | 3 | 3 | — | 3 | — | — |
| Number studied | 6 | 20 | — | 20 | — | — | |
| Recurrence risk (%) | 50 | 15 | — | 15 | — | — | |
| Moesman20 | Number affected | 7 | — | — | — | — | — |
| Number studied | 11 | — | — | — | — | — | |
| Recurrence risk (%) | 63.6 | — | — | — | — | — | |
| Total | Number affected | 17 | 404 | 37 | 441 | 8 | 7 |
| Number studied | 27 | 4924 | 466 | 5390 | 834 | 997 | |
| Recurrence risk (%) | 63.0 | 8.2 | 7.9 | 8.2 | 1.0 | 0.7 | |
| (95% CI) | (42 to 81) | (7.4 to 9.0) | (5.6 to 10.7) | (7.4 to 8.9) | (0.2 to 1.7) | (0.1 to 1.4) | |
| Recurrence risk ratio | 630 | 82 | 79 | 82 | 10 | 7 |