GH1 and hyperinsulinemic hypoglycemia, familial, 4: As the main laboratory findings in this disease include insulin-like growth factor-I (IGF-I) deficiency (IGFD) and normal GH levels, in current classifications it is labelled as primary IGFD, which is considered to be synonymous of GHI, while secondary IGFD is equivalent to GH deficiency (GHD) [4].