A gene located at 17q21. All primates contain five tandemly linked genes of similar structure. In humans, the sequence is 5′-GH1-CSHP1-CHS1-GH2-CSH2-3′. GH1 codes for the hGH secreted by the pituitary gland. The other four genes are expressed in the placenta. GH2 is a pseudogene (q.v.), which codes for an inactive form of hGH that differs from normal hGH by 13 amino acids. GSH1 and CSH2 encode hCS, and CSHP1 encodes a variant form of hCS. Each of the five genes contains five exons, which are interrupted at identical positions by small introns. All have similar promotors and poly-A addition sites. The five genes presumably evolved from duplications of a common ancestral gene, followed by codon mutations. See hereditary growth hormone deficiency, pituitary dwarfism.
Subjects: Genetics and Genomics.