[Growth hormone resistance. Genetic defects and therapy in Laron syndrome and similar conditions].

Two siblings with Laron syndrome from Cambodia, Asia, are described. They fulfilled the strict diagnostic criteria for the syndrome, including an IGF-1 generation test with growth hormone. The growth hormone binding protein levels where lower than 2%. Genetic investigation revealed an unique structural abnormality of the extracellular domain that included deletion of exon 5 (Mary An Berg and Uta Francke, Beckman Center, Stanford University, California, USA. Personal communication, 1995). In May 1994 the height of the boy (eight years old) was 87.6 cm and the girl (six years old) was 78.6 cm. Treatment was started with IGF-I (Pharmacia AB, Sweden) 40 micrograms/kg b.i.d. subcutaneously and was progressively increased to 120 micrograms/kg. The pre-treatment growth velocities were 2.7 cm/year (boy) and 2.4 cm/year (girl). The mean growth velocities after 30 months of therapy were 5.7 cm/year (boy) and 6.3 cm/year (girl). There were no adverse events during IFG-I treatment. The genetics, heterogeneity and therapy of growth hormone insensitivity are discussed.