TABLE 3.
Bone histomorphometric findings in two subjects with a heterozygous missense mutation p.G218R in ARHGAP25 and a pathological fracture history
| Parameter | II‐2 (index, 69 years) | II‐4 (sister, 64 years) | ||||
|---|---|---|---|---|---|---|
| Value | Reference mean ± SD (F, 65–74 years) | Z‐score | Value | Reference mean ± SD (F, 55–64 years) | Z‐score | |
| BV/TV (%) | 6.76 | 19.56 ± 5.62 | −2.28 | 8.20 | 20.79 ± 4.37 | −2.88 |
| OV/BV (%) | 0.14 | 1.2 ± 0.87 | −1.22 | 0.11 | 2.17 ± 1.14 | −1.81 |
| O.Th (μm) | 2.43 | 8.31 ± 1.99 | −2.95 | 6.30 | 9.16 ± 1.94 | −1.47 |
| OS/BS (%) | 1.78 | 14 ± 6.64 | −1.84 | 7.80 | 16.7 ± 6.99 | −1.27 |
| Ob.S/BS (%) | 0.00 | 3.11 ± 2.75 | −1.13 | 0.24 | 6.05 ± 3.83 | −1.52 |
| ES/BS (%) | 2.16 | 3.66 ± 1.69 | −0.89 | 0.93 | 4.14 ± 2.12 | −1.51 |
| Oc.S/BS (%) | 0.34 | 0.59 ± 0.73 | −0.34 | 0.15 | 0.82 ± 0.80 | −0.84 |
| Tb.Th (μm) | 63.35 | 131.3 ± 28.10 | −2.42 | 73.00 | 133 ± 34.40 | −1.74 |
| Tb.Sp (μm) | 873.00 | 690.5 ± 178.00 | 1.03 | 822.00 | 626.9 ± 94.40 | 2.07 |
| Tb.N (n/mm) | 1.07 | 1.49 ± 0.29 | −1.45 | 1.10 | 1.59 ± 0.23 | −2.13 |
| MS/BS (%) | 0.70 | 5.79 ± 4.38 | −1.16 | 4.50 | 7.77 ± 4.20 | −0.78 |
| MAR (μm/d) | 0.467 | 0.477 ± 0.078 | −0.09 | 0.471 | 0.526 ± 0.044 | −1.27 |
| BFR/BS (μ3m/μ2m/year) | 1.19 | 10.1 ± 7.99 | −1.12 | 7.80 | 15.0 ± 8.0 | −0.90 |
| Mlt (days) | 13.25 | 68 ± 55.5 | −0.99 | 23.17 | 43.5 ± 24.5 | −0.83 |
| FB.V (%) | Traces | None | ||||
Notes: Z‐scores were calculated using age‐specific reference values according to Recker et al.( 17 ) Values above 1.5 SD are in italics and values below −1.5 SD are in bold.
Abbreviations: BFR/BS, bone formation rate/bone surface; BV/TV, bone volume/total volume; ES/BS, eroded surface/bone surface; F, female; FB.V, fibrosis; MAR, mineral apposition rate; Mlt, mineralization lag time; MS/BS, mineralizing surface/bone surface; O.Th, osteoid thickness; Ob.S/BS, osteoblast surface/bone surface; Oc.S/BS, osteoclast surface/bone surface; OS/BS, osteoid surface/bone surface; OV/BV, osteoid volume/bone volume; SD, standard deviation; Tb.N, trabecular number; Tb.Sp, trabecular separation; Tb.Th, trabecular thickness.