A patient of short stature with normal GH secretion, but a low serum IGF-I level.

We report the case of a 7-year-old patient of short stature who had normal GH secretion, but a very low serum IGF-I level. On admittance, his height and weight were 102.2 cm (-3.8S.D.) and 15.7 kg (-1.8S.D.), respectively. His bone age was 2 years and 8 months. The serum GH responses to insulin, glucagon and L-dopa were all normal. GH secretion during sleep was also normal, but the serum IGF-I level was very low (29 ng/ml). The serum IGF-I level was greatly increased by the administration of GH. No mutation was detected in the GH-1 gene. His height velocity was noticeably improved by GH treatment.