Molecular basis for familial isolated growth hormone deficiency.

Abstract

Nuclear DNA from 4 individuals with familial isolated growth hormone (somatotropin) deficiency (IGHD) type A was studied by restriction endonuclease analysis. By using 32P-labeled human growth hormone (hGH) c[complementary]DNA sequences as a probe, patterns seen after various digestions indicated that these individuals were homozygous for a deletion of at least 7.5 kbases of DNA. This deletion includes the gene that encodes the normal growth hormone but does not include the variant growth hormone gene. Restriction patterns of DNA from all family members agreed with an autosomal recessive mode of inheritance of the deletion that correlates wth the clinical phenotype. Independent assortment of the 2 types of hGH genes also suggests that these genes are nonallelic. In these families, IGHD type A apparetly is caused by deletion of the normal hGH genes, this disorder can occur in the presence of variant hGH genes.