Phase 3 Study to Evaluate the Efficacy and Safety of Human Growth Hormone Injection (Sinotropin AQ) for the Treatment of Children With Idiopathic Short Stature

• Human Growth Hormone (hGH) (Drug): This product is human growth hormone (hGH) injection (Sinotropin AQ). Usage and dosage: 0.15 IU/kg/day (0.05 mg/kg/day), once daily, administered by subcutaneous injection.
• Human Growth Hormone (hGH) (Drug): This product is human growth hormone (hGH) injection. Usage and dosage: 0.15 IU/kg/day (0.05 mg/kg/day), once daily, administered by subcutaneous injection

Primary outcomes

• The value of Annual Height velocity [At the end of 52 weeks of treatment]: The value of Annual Height velocity (HV, cm/year)

Secondary outcomes

• The change of ΔHT SDS value [At all visit points from baseline to week 52]: The change from baseline in height SDS (ΔHT SDS)
• The change of IGF-1 SDS value [At all visit points from baseline to Week 52]: The change of insulin-like growth factor-1 standard deviation score value
• The change of height velocity value (ΔHV) [At all visit points from baseline to Week 52]: The change from baseline in height velocity(ΔHV)
• The change of bone age relative to change of chronological age(ΔBA/ΔCA) value [At all visit points from basline to week 52]: The change of bone age (BA) relative to the change in chronological age (CA) from basline to end of 52-week treatment
• The safety of human growth hormone injection [Baseline, Week 13, Week 26, Week 39, and Week 52]: Evaluate all TEAEs, SAEs, and clinically significant abnormalities in laboratory tests, vital signs, and physical examination.
• Immunogenicity of Human Growth Hormone Injection [At all visit points from baseline to week 52]: Assessment of anti-GH and neutralizing antibody incidence

Sex: All, ages: 3 Years to 11 Years

Inclusion Criteria:

* 1\. Tanner stage I (prepubertal) at informed consent: males aged 3 to <11 years ; females aged 3 to <10 years ;
* 2\. At screening, height < -2 standard deviations (SD) for age and sex (height reference per Appendix 1);
* 3\. Peak GH ≥10.0 ng/mL in any growth hormone (GH) stimulation test;
* 4\. Bone age minus chronological age ≤ 1 year.

Exclusion Criteria:

* 1.Closed epiphyses (skeletally mature)；
* 2.Severe allergic diathesis, or known hypersensitivity to growth hormone or any of its excipients；
* 3.History of malignancy or current active malignancy；
* 4.Systemic chronic diseases, including but not limited to moderate-to-severe anemia, hypothyroidism, chronic kidney disease, cardiovascular disease (e.g., dilated cardiomyopathy), psychiatric disorders, or congenital anomalies that require clinical intervention per the investigator's judgment.
* 5.Patients with a prior diagnosis of intracranial hypertension;
* 6.Patients with congenital skeletal dysplasia, or scoliosis ≥15° (or moderate or greater), limping (gait disturbance), and patients with a prior diagnosis of slipped capital femoral epiphysis ;
* 7.Other types of growth and developmental disorders, including confirmed or highly suspected growth hormone deficiency (GHD), Noonan syndrome, Prader-Willi syndrome, Russell-Silver syndrome, Turner syndrome, small for gestational age (SGA), short stature due to SHOX gene defects, and short stature of other identified causes;
* 8\. Patients with a confirmed diagnosis of diabetes mellitus, or fasting blood glucose ≥6.1 mmol/L on two consecutive measurements.