Genetic mapping of the human growth hormone-releasing factor gene (GHRF) using two intragenic polymorphisms detected by PCR amplification.

We have analyzed the human growth hormone-releasing factor (GHRF) gene by high-resolution restriction mapping of its PCR amplification products. Two intragenic PCR fragment length polymorphisms (PCRFLPs) were detected in introns A and C of the GHRF gene, whose heterozygosities are 40 and 7%, respectively. Linkage analysis using the CEPH panel showed that GHRF is linked to several markers on chromosome 20 and assigned the GHRF locus to a region near the centromere between D20S27 (assigned to 20p12.1-p11.23) and D20S16 (assigned to 20q12). These intragenic PCRFLPs and the tightly linked polymorphisms should provide useful markers for linkage studies of GHRF alleles in familial disorders of growth such as isolated growth hormone deficiency.