Table 1. Summary of the main clinical and biochemical findings in the three pediatric patients with severe bone deformations and nephropathic cystinosis.
| Usual values | Patient 1 | Patient 2 | Patient 3 | |
|---|---|---|---|---|
| Age at diagnosis (years) | 5 | 2 | 0.9 | |
| Age at onset of bone symptoms (years) | 7 | 10 | 10 | |
| Age at BB (years) | 13 | 14 | 20 | |
| Renal function at the time of BB (ml min−1 1.73 m−2) | >90 | 13 (conservative management) | 72 (conservative management) | 22 (conservative management) |
| Thyroid status | Normal | Normal | Hypothyroidism treated with L-thyroxine | |
| Copper status | Normal | Copper deficiency | Copper deficiency | |
| Treatment with growth hormone | Yes | No | Yes | |
| Bicarbonates (average during the year before BB, mmol l−1) | 19–24 | 22 | 24 | 23 |
| Total calcium (average during the year before BB, mmol l−1) | 2.20–2.55 | 2.19 | 2.39 | 2.35 |
| Phosphorus (average during the year before BB, mmol l−1) | 0.74–1.45 | 1.39 | 1.37 | 1.19 |
| PTH levels (average during the year before BB, pg ml−1) | 15–65 | 119 | 15 | <2.5 |
| 25 OH vitamin D levels (average during the year before BB, mmol l−1) | 75–150 | 71 | 31 | Not performed |
| Hemi-cystine levels (leukocyte cystin in nmol per mg of protein) | <0.4 | Between 0.3 and 0.9 during the year before surgery | 0.01–1 | 0.7 |
| Daily dose of cysteamine bitartrate (mg kg−1) | 44 | 40 | 27 | |
| X-ray analysis | No evidence for abnormal mineralization | Sequelae of rickets | No evidence for abnormal mineralization | |
| BB results | Normal mineralization with active areas for both bone resorption and formation | Active areas of mineralization and bone formation, with extended and unusual areas of bone resorption | Diffuse defective mineralization. Active osteoclasts and little osteoblastic activity | |
| Cystine crystals (BB) | No | No | No |
Abbreviation: BB, bone biopsy.