I. Definition of ISS ISS refers to an individual whose height is more than 2SD below the average of the normal group with the same age and sex, and there are no systemic, endocrine, nutritional diseases or chromosomal abnormalities, especially the birth weight and growth hormone levels of children with ISS are normal. In 2003, authorities in eight countries, including the United States, approved the use of growth hormone therapy for children whose height was below -2.25 SDS (1.2 percentile). This workshop concluded that growth hormone therapy should be used in children below -3 – 2 SDS. However, the age of the child should be considered before treatment is started. 5 to early adolescence is preferred. The dose of GH approved by FDA for the treatment of ISS is 0.30~0.37mg/kg/w. IGF-1 can be used to assess the patient’s compliance and sensitivity to GH. The course of GH treatment should be discontinued when the adult height is approached (growth rate <2cm/year, and/or bone age >16 years for boys and >14 years for girls); 2. The drug should be discontinued when the height reaches the normal range for adults (above -2SDS) or another acceptable level.