Cm. Schnitzler et al., METABOLIC BONE-DISEASE IN BLACK TEENAGERS WITH GENU-VALGUM OR GENU-VARUM WITHOUT RADIOLOGIC RICKETS - A BONE HISTOMORPHOMETRIC STUDY, Journal of bone and mineral research, 9(4), 1994, pp. 479-486
Calcium deficiency in black (African) children can cause rickets and o
steomalacia with severe limb deformities. It is not known whether blac
k teenagers with genu valgum or varum but without radiologic rickets s
uffer from a related disorder. To examine this question we studied 26
such patients by iliac crest bone biopsy and serum and urine biochemis
try: 12 patients (46%) had osteopenia with normal or low bone turnover
, 5 (19%) mildly increased bone turnover, 4 (15%) histologic hyperpara
thyroidism, 2 (8%) preosteomalacia, and 3 (12%) osteomalacia (with fea
tures of hyperparathyroidism). Radiographs did not reflect the severit
y of the bone disease. Serum calcium levels correlated inversely with
eroded mineralized surface (p < 0.001), osteoid surface (p < 0.01), os
teoid thickness (p < 0.001), mineralization lag time (p < 0.001), and
1,25-(OH)2 vitamin D (p < 0.005), and 1,25-(OH)2 vitamin D correlated
positively with osteoid surface (p < 0.05), osteoid thickness (p < 0.0
5), osteoid volume (p < 0.01), eroded surface (p < 0.05), and eroded m
ineralized surface (p < 0.0005). Tubular reabsorption of phosphate and
25-OH vitamin 1) levels were normal, and 1,25-(OH)2 vitamin D levels
were normal to high. This suggests that calcium deficiency may have ca
used the increase in bone turnover and the mineralization defects. The
most severe osteomalacia was found in males aged 16-19 years. We cann
ot explain the cause of the osteopenia. We conclude that all patients
had bone disease.