Growth hormone deficiency (GHD), also known as pituitary dwarfism, is a growth disorder caused by insufficient secretion of GH due to hypothalamic-anterior pituitary dysfunction. Clinical manifestations: Growth is slowed down after 5 months of life, which is obvious at 1-2 years of age, and the degree of growth retardation increases with age. Generally, height is lower than 2 standard deviations (2SD) or lower than the 3rd percentile of the mean height for the same sex’ age; in severe cases, it is lower than 3SD, or lower than -1.5SD of the median height of both parents Bone age: all children with GHD have delayed bone age, generally delayed by 2 years or more.