To evaluate the effectiveness of rhGH (Recombinant human growth hormone) injection for improving motor development in patients with PWS.

Inclusion Criteria:

• 1.Signed informed consent from legal guardian of the subjects;
• Subjects are willing and able to cooperate to complete scheduled visits, treatment plans and laboratory tests and other procedures;
• Diagnosed as PWS by gene test;
• Age: 1 month (30 days after birth) - 5 years of age;
• Male or female;
• Calculated by Peabody Developmental Motor Scale, total motor quotient, gross motor quotient or fine motor quotient is less than 90 points;
• Thyroid function is within the normal reference range or remained within the normal reference range by substitution therapy;
• No history of rhGH therapy before.

Exclusion Criteria:

• Subjects with abnormal liver or kidney function;
• Subjects with obvious central sleep apnea and/or moderate or severe obstructive sleep apnea, acute lung infection;
• Subjects with chronic diseases that have long-term effects on bone metabolism and body composition;
• Subjects with congenital skeletal dysplasia, or spine scoliosis with moderate and above degree requiring treatment or lameness;
• Subjects with history of congenital heart disease, or an echocardiogram showing that the structural abnormalities require surgery or interventional therapy or that the left ventricular ejection fraction is <40%, or the abnormal electrocardiogram requiring intervention;
• Subjects with history of convulsions or epilepsy;
• Subjects with other systemic chronic diseases;
• Subjects with diagnosed tumors;
• Subjects with family history of cancers, a previous history of cancer, or considered to be a high risk of cancer combinating other information;
• Subjects with mental disease;
• Subjects with diabetes, or abnormal fasting glucose and researchers believe that may affect the safety of the subject;
• Subjects with severe obesity;
• Subjects with highly allergic constitution or allergy to proteins or investigational product or its excipient;
• Subjects who took part in other clinical trials within 3 months ;
• Subjects who received drug treatment that may interfere with GH secretion or GH action within 3 months;
• Other conditions in which the investigator preclude enrollment into the study