Table 2. Clinical characteristics in relation to collagen I mutation.
| Individuals (n) | BMD baseline (Z-score) | Height baseline (Z-score) | Number of fractures (per year) | Number of fractures children (per year) | Vertebral fractures (yes) | Vertebral fractures children (yes) | Blue sclera (yes) | Dentinogenesis imperfect (yes) | |
|---|---|---|---|---|---|---|---|---|---|
| Type I quant. | 83 | −2.57 | −0.53 | 0.59 | 0.72 | 79% | 72% | 100% | 0% |
| Type I qual. | 40 | −2.99 | −1.67 | 0.58 | 0.68 | 62% | 64% | 100% | 42% |
| Type I quant. vs qual. P-value | — | NS | <0.0001 | NS | NS | NS | NS | By definition | <0.0001 |
| All qual. α1-chain | 40 | −4.13 | −3.41 | 2.55 (1.36III) | 3.63 | 87% | 91% | 68% | 57% |
| All qual. α2-chain | 49 | −3.91 | −2.93 | 0.97 | 1.07 | 74% | 75% | 89% | 54% |
| All qual. α1- vs α2-chain P-value | — | NS | NS | NS | NS | NS | NS | 0.0511 | NS |
| Helical gly α1-chain | 38 | −4.43 | −3.61 | 1.30 | 1.31 | 93% | 93% | 70% | 65% |
| Helical gly α2-chain | 36 | −3.94 | −2.87 | 0.92 | 1.01 | 72% | 73% | 88% | 53% |
| Helical gly α1- vs α2-chain P-value | — | NS | NS | NS | NS | NS | NS | NS | NS |
| Serine α1-chain | 20 | −5.0 | −3.62 | 1.53 | 1.29 | 93% | 89% | 56% | 79% |
| Serine α2-chain | 20 | −3.5 | −1.61 | 0.64 | 0.63 | 57% | 25% | 89% | 39% |
| Serine α1- vs α2-chain P-value | — | 0.0146 | 0.0154 | 0.0351 | NS | 0.0352 | 0.0212 | 0.0523 | 0.0201 |
| Collagen I mutation | 42I/155II | Not relevant | Not relevant | Not relevant | Not relevant | Not relevant | Not relevant | 60% | 30% |
| No collagen I mutation | 17I/32II | Not relevant | Not relevant | Not relevant | Not relevant | Not relevant | Not relevant | 24% | 0% |
| Collagen vs no collagen mutation P-value | — | — | — | — | — | — | — | 0.0204 | <0.0001 |
Abbreviation: NS, not significant. Comparison of different clinical characteristics in individuals with/without various collagen I mutation types defined for each column. Children defined as 18 years or younger at database lock (31 December 2013).