This is a Phase IV, multicenter, open-label, single-arm study of somatropin (rDNA origin) (Nutropin AQ v1.1) in pre-pubertal children with growth hormone deficiency (GHD) naïve to prior recombinant human growth hormone (rhGH) treatment. The study is designed to characterize the immunogenicity profile of somatropin (rDNA origin) injection when administered daily subcutaneously for 12 months. The clinical impact of immunogenicity will also be assessed.

Inclusion Criteria:

• Bone age less than equal to (</=) 9 years (females) or </= 11 years (males) as determined by X-ray of the left hand and wrist using Greulich and Pyle method and obtained within the 12 months prior to enrollment
• Prepubertal (Tanner I) males and females by physical examination
• Diagnosis of GHD (stimulated GH less than [<] 10 nanograms per milliliter [ng/mL]) by two standard pharmacologic tests obtained up to 12 months prior to informed consent/assent
• Normal thyroid function test within the 12 months prior to informed consent/assent
• Normal complete blood counts within 12 months prior to informed consent/assent
• Documentation of prior height and weight measurements, with height standard deviation score (SDS) </= 5th percentile for idiopathic isolated GHD participants

Exclusion Criteria:

• Any previous rhGH treatment
• Short stature etiologies other than GHD
• Acute critical illness or uncontrolled chronic illness, which in the opinion of the investigator and medical monitor, would interfere with participation in this study, interpretation of the data, or pose a risk to participant safety
• Chronic illnesses such as inflammatory bowel disease, celiac disease, heart disease, and diabetes
• Bone diseases such as achondroplasia or hypochondroplasia, intracranial tumor, irradiation, and traumatic brain injury
• Participants receiving oral or inhaled chronic corticosteroid therapy (greater than [>] 3 months) for other medical conditions other than central adrenal insufficiency
• Participants who require higher (2 times or greater than maintenance) doses of corticosteroids for more than 5 days in the 6 months prior to enrollment in the study
• Participants with active malignancy or any other condition that the investigator believes would pose a significant hazard to the participant if rhGH were initiated
• Females with Turner syndrome regardless of their GH status
• Prader-Willi syndrome regardless of GH status
• Born small for gestational age regardless of GH status
• Presence of scoliosis requiring monitoring
• Previous participation in another clinical trial or investigation of GH, treatment for growth failure, or treatment with a biologic agent
• Participants with closed epiphyses
• Participants with a known hypersensitivity to somatropin, excipients, or diluent