NO CORRELATION OF GROWTH-HORMONE RECEPTOR GENE MUTATION P561T WITH BODY HEIGHT

Analysis of the growth hormone receptor (GHR) gene in GH insensitivity syndrome revealed various mutations, mainly in the gene encoding the extracellular domain of GHR. On the other hand, the mutation of the ge ne encoding the cytoplasmic domain of GHR was not found. We have repor ted, in the cytoplasmic domain of a GHR gene, mutation P561T in a pati ent with Noonan syndrome who showed a blunted insulin-like growth fact or I (IGF-I) response to an acute injection of GK. However, her mother possessing the same mutation had no growth failure. To clarify the si gnificance of the GHR gene mutation P561T, 96 volunteers (41 males age d 21-80 years; 55 females, aged 20-80 years) were tested for the prese nce of this mutation. By the polymerase chain reaction-restriction fra gment length polymorphism (PCR-RFLP) method, three of the 41 males and 11 of the 55 females examined revealed heterozygous missense mutation P561T. The body height (cm) was 168 +/- 5.3 (mean +/- so) in three ma les with the mutation and 164.1 +/- 5.8 in 38 males without the mutati on. The difference between them was not statistically significant. The body height in 11 females with the mutation was 152.6 +/- 5.4, which did not differ significantly from 151.3 +/- 6.2 in 44 females without the mutation. These findings suggest that the heterozygous missense mu tation P561T in the cytoplasmic domain of GHR does not play a signific ant role in determining the final body height.