GROWTH-HORMONE AND IGF1 PROFILE IN SHORT CHILDREN WITH OSTEOPETROSIS

Osteopetrosis is commonly associated with short stature. To identify t he cause, 8 children with osteopetrosis and short stature were studied . One showed evidence of renal tubular acidosis, none showed evidence of anaemia, and all were clinically and biochemically euthyroid. Growt h hormone profile was assessed using night sampling (8 patients), grow th hormone provocative testing using insulin-induced hypoglycaemia (6 patients), and L-dopa-propranolol (8 patients). The mean nocturnal gro wth hormone values taken at 60 and 90 min after onset of sleep and at 4 a.m. were 5.5, 12.8, and 11.5 mu/L respectively. The peak stimulated growth hormone mean values with the insulin-induced hypoglycaemia (gl ucose 1.6-3.0 mmol/L, mean = 2.2) was 14 mu/L (range 7.3-24.5 mu/L) an d with the L-dopa-propranolol was 25.6 mu/L (range 12.3-49 mu/L). IGF1 levels taken at 0 and 120 min of insulin-induced hypoglycaemia (0 min for L-dopa-propranolol), and at 120 min of L-dopa-propranolol, showed normal values for age. We conclude that: (1) growth hormone profiles in these children are normal; (2) tissue unresponsiveness to growth ho rmone and/or IGF1 is not likely to be the cause of short stature in ch ildren with osteopetrosis; and (3) osteopetrosis per se is not an indi cation for assessment of growth hormone status.