Identification of novel human GH-1 gene polymorphisms that are associated with growth hormone secretion and height.

Height, which is partially determined by GH secretion, is genetically influenced. The purpose of this study was to identify polymorphisms in the GH-1 gene, which are associated with altered GH production. The subjects included prepubertal short children with GH insufficiency without gross pituitary abnormalities (n = 43), short children with normal GH secretion (n = 46), and normal adults (n = 294). A polymorphism in intron 4 (P-1, A or T at base 1663) was identified. Two additional polymorphic sites (P-2, T or G at base 218, and P-3, G or T at base 439) in the promoter region of the GH-1 gene were also identified and matched with the P-1 polymorphism (A or T, respectively) in more than 90% of the subjects. P-1, P-2, and P-3 were considered to be associated with GH production, and the results of P-2 are explained as a representative in this abstract. For example, the allele frequency of T at P-2 in prepubertal short children with GH insufficiency without gross pituitary abnormalities (58.1%) was significantly different from that in short children with normal GH secretion and normal adults (37.0% and 43.5%, respectively; P < 0.001). Furthermore, significant differences were observed in maximal GH peaks in provocative tests (11.1 vs. 18.2 ng/mL, P = 0.006), insulin-like growth factor I SD scores (SDS) (-2.4 vs. -0.8, P < 0.0001), and height (Ht) SDS (-3.7 vs. -3.0, P = 0/001) in children with the T/T or G/G genotypes at P-2, respectively. In the entire study group, significant differences in insulin-like growth factor SDS (T/T, -0.9; G/G, -0.2; P = 0.0009) and Ht SDS (T/T, -1.0; G/G, -0.4; P = 0.022) were observed between the T/T and G/G genotypes at P-2. These data indicate that GH secretion is partially determined by polymorphisms in the GH-1 gene, which explain some of the variations in GH secretion and Ht.