Table 3.

Results of Bone Histomorphometry

	Controls	Proband 1	Proband 2	OI Type Ia	OI Type VIIb
n	10			32	4
Age at biopsy, y	7.0–10.9	9	10	7.9 ± 2.9	3.6 ± 0.7
Structural parameters
Cortical width, mm	0.97 ± 0.37	0.25	0.42c	0.52 ± 0.20	0.38 ± 0.13
Bone volume per tissue volume, %	22.4 ± 4.2	8.14	NA	11.0 ± 5.2	12.3 ± 1.5
Trabecular thickness, μm	129 ± 17	58.2	65.08	105 ± 25	101 ± 15
Trabecular number, 1/mm	1.73 ± 0.17	1.39	NA	1.03 ± 0.39	1.24 ± 0.17
Bone surface/bone volume, mm2/mm3	16.8 ± 2.5	34.36	30.73	19.8 ± 4.7	20.2 ± 2.7
Bone formation parameters
Osteoid thickness, μm	5.9 ± 1	5.3	4.6	5.5 ± 1.7	5.3 ± 0.8
Osteoid volume per bone volume, %	2.64 ± 1.04	7.7	6.3	5.2 ± 2.6	5.5 ± 1.0
Osteoid surface per bone surface, %	29.1 ± 12.9	54.0	51.9	48 ± 14	53 ± 4
Osteoblast surface per bone surface, %	8.2 ± 4.4	8.9	22.8	19.4 ± 9.5	24.1 ± 2.3
Osteoblast surface per osteoid surface, %	28.8 ± 15.1	11.7	44.1	39 ± 14	45 ± 3
Mineral apposition rate, μm/d	0.95 ± 0.07		0.7	0.73 ± 0.18	0.71 ± 0.12
Mineralizing surface per bone surface, %	14.9 ± 4.5		28.8	23.1 ± 9.7	26 ± 5
Bone formation rate per bone surface, mm3/mm2/y	51.8 ± 6.1		77.3	77 ± 34	135 ± 45
Adjusted apposition rate, μm/d	0.47 ± 0.18		0.4	0.35 ± 0.14	0.37 ± 0.12
Mineralization lag time, d	14.1 ± 4.3		11.2	16.5 [12.5–19.8]	15 ± 4
Bone resorption parameters
No. of osteoclasts per bone surface/mm	0.36 ± 0.16	0.1	0.1	0.47 ± 0.29	Not defined
Osteoclast surface per bone surface, %	1.29 ± 0.62	0.4	0.4	1.37 [1.05–1.70]	2.3 ± 0.6
Eroded surface per bone surface, %	17. 0 ± 6.0	12.9	21.9	15.6 [13.7–21.8]	22.6 ± 6

Abbreviation: NA, not available. Control data are expressed as mean ± SD for healthy children from Glorieux et al (22).

^aReference data from 19 children with OI type I (29) selected from a larger cohort published by Rauch et al (23).

^bOI type VII data from Ward et al (24).

^cCortical width is calculated as mean width from two cortices. In the bone biopsy sample from proband 2, only one cortex was available.