Description, number, and type of affected sibling pairs in the 242 families studied
| Type of affected sib pair | ||||||
|---|---|---|---|---|---|---|
| No of affected sib pairs in each family | No of families | CD | UC | Mixed | Total affected siblings | Other affected relatives |
| To arrive at the total number of sib pairs in each affected family, imagine sibs A, B, C, D and E; two affected sibs are required for one sib pair, for example, AB; three affected siblings make three sib pairs, for example, AB, BC, AC; four affected siblings make six sib pairs AB, AC, AD, BC, BD, CD; if D and E are the step brother/sister of A, B and C and all are affected, there are four sib pairs AB, AC, BC, DE. See also Hauser and colleagues.43 | ||||||
| CD, Crohn's disease; UC, ulcerative colitis. | ||||||
| 1 | 199 | 96 | 59 | 44 | 398 | 112 |
| 2 | 4 | 3 | 4 | 1 | 16 | — |
| 3 | 32 | 26 | 46 | 24 | 96 | 4 |
| 4 | 3 | 8 | 3 | 1 | 15 | — |
| 6 | 4 | 15 | 3 | 6 | 16 | 1 |
| Total | 242 | 148 | 115 | 76 | 541 | 117 |