Detection of point mutation for human growth hormone in patients with anti-pituitary antibody positive type 1 diabetes mellitus.

We investigated genetic mutations in the coding region of the human growth hormone (hGH) gene in anti-pituitary antibody (APA)-positive patients with type 1 diabetes mellitus (n = 6) or autoimmune thyroid diseases (n = 10) and in APA-negative, healthy controls (n = 10). A point mutation in the hGH gene was discovered in two patients with type 1 diabetes mellitus. No mutations were found in the hGH gene in control subjects, patients with autoimmune thyroid diseases (Hashimoto's thyroiditits, Graves' disease) or in the remaining four patients with type 1 diabetes mellitus. The mutation was located in the coding region for the second amino acid in the N-terminal region of hGH. This point mutation was identified in codon 2 in exon 2 of the hGH gene. We successfully developed an allele-specific amplification method for detecting this mutation using the polymerase chain reaction.