THE EFFECT OF CUSHINGS-DISEASE ON BONE-MINERAL DENSITY, BODY-COMPOSITION, GROWTH, AND PUBERTY - A REPORT OF AN IDENTICAL ADOLESCENT TWIN PAIR

As endogenous Gushing's syndrome (GS) in children occurs during a crit ical developmental period, when the majority of peak bone mass is acqu ired, we hypothesized that children with CS might be at an increased r isk of osteoporosis. To determine the effects of CS on bone density, b one metabolism, and growth, we studied a 15-yr-old female identical tw in pair, one of whom had CS (twin A), and the other of whom was health y (twin B). Before therapy for GS, twin A showed a severe loss of bone mineral density [BMD; -3.2 so at the lumbar spine (LS)] compared to t win B (-0.1 SE), which in twin A was associated with low serum osteoca lcin levels and urinary pyridinium cross-link excretion. Cure of CS in twin A led to a marked increase in these bone markers, suggesting a s tate of active bone remodeling. After 27 months of follow-up, even tho ugh twin A's BMD improved significantly, it still remained abnormal [- 1.9 so at LS compared with that of twin B (0 SD)], suggesting that twi n A continued to be at increased long term risk of osteoporosis. In ad dition, as a consequence of CS, twin A's final height was 21 cm less t han that of her identical twin. We recommend that all children with CS should have BMD monitored after treatment to determine the longterm r isk of osteoporosis.