Normal bone density of the wrist and spine and increased wrist fractures in girls with Turner's syndrome.

Turner's syndrome is associated with multiple skeletal abnormalities, including osteoporosis. We evaluated the hypothesis that girls with Turner's syndrome may have deficient bone density before the expected age of pubertal onset (9-13 yr) by comparing the bone mineral content of the wrist and lumbar spine in 78 girls with Turner's syndrome (4-13 yr old) and 28 normal prepubertal girls who were matched for age, bone age, body mass index, or height age. The bone mineral content of the wrist and spine was measured by single photon absorptiometry (SPA) and dual photon absorptiometry (DPA), respectively. SPA values for girls with Turner's syndrome vs. normal subjects (4-6.9, 7-9.9, and 10-12.9 yr old) were (mean +/- SD) 0.27 +/- 0.05 vs. 0.36 +/- 0.05, 0.35 +/- 0.06 vs. 0.41 +/- 0.06, and 0.41 +/- 0.05 vs. 0.45 +/- 0.03 g/cm2, respectively. SPA values in the Turner's syndrome girls were decreased compared to those in normal prepubertal girls, matched for age (P less than 0.0001), bone age, (P less than 0.001), and body mass index (BMI; P less than 0.0001), but not for height age. DPA values for girls with Turner's syndrome vs. normal girls in the same age categories were 0.65 +/- 0.06 vs. 0.70 +/- 0.09, 0.77 +/- 0.08 vs. 0.79 +/- 0.09, and 0.83 +/- 0.12 vs. 0.78 +/- 0.07 g/cm2. DPA values in Turner's syndrome girls (as a group) were decreased compared to those in normal prepubertal girls matched for age (P less than 0.05) and BMI (P less than 0.02), but not for bone age or height age. The annual incidence rate of wrist fractures in Turner's syndrome girls (9.1 of 1000) was significantly increased compared to the reported annual incidence rate in normal children (3.5 of 1000; P less than 0.003). We conclude that prepubertal-aged girls with Turner's syndrome (less than 13 yr old) have normal bone density for height age, but significantly decreased bone density of the wrist for chronological age, bone age, and BMI. They also have significantly more wrist fractures than normal girls, but it is not clear that this is related to their bone density.