A Study of the Genetic Basis of Response to Growth Hormone Treatment in Children With Idiopathic Short Stature

Inclusion Criteria: * Signed consent/parental consent and patient assent for minor children obtained before any study-related activities (study-related activities are any procedure related to recording of data according to the protocol). * Patient has been diagnosed with Idiopathic Short Stature (ISS) and received at least 1 year of GH therapy. * Patient was prepubertal at initiation of and throughout first year of GH therapy, as determined by the treating physician and patient medical records. * Patient had no prior exposure to growth promoting therapy prior to initiation of GH therapy, including but not limited to growth hormone, IGF-I and ghrelin analogues. * Age at initiation of GH therapy: * Boys: Age above or equal to 3 years and below 11.0 years. * Girls: Age above or equal to 3 years and below 10.0 years. * Impaired height prior to initiation of GH therapy defined as at least 2 standard deviations below the mean height for chronological age and sex according to local growth reference charts. In the absence of local reference charts, the standards of Centres for Disease Control and Prevention should be used. * GH deficiency has been excluded via GH stimulation test (cut point of 7 nanograms per milliliter \[ng/ml\]) or other clinical and biochemical criteria according to local clinical practice. * Patient fits within one of the following response groups: * Change in Height Standard Deviation Score (SDS) after approximately the first year (+/- 2 months) of GH therapy greater than (\>) 1.0. * Change in Height SDS after approximately the first year (+/- 2 months) of GH therapy less than (\<) 0.4. Exclusion Criteria: * Previous participation in this study. Participation is defined as having given informed consent in this study. * Mental incapacity, unwillingness or language barriers precluding adequate understanding, cooperation or informed consent. * Receipt of any investigational medicinal product within 3 months before or during the first year of GH therapy that could influence response to GH therapy. * Concomitant illness within 3 months before or during the first year of GH therapy that could (positively or negatively) influence the first year of GH therapy. Exception: Attention Deficit Hyperactive Disorder and its treatment can be included but should be recorded. * Children with suspected or confirmed growth hormone deficiency according to local practice. * Concomitant use of medication including gonadotropin-releasing hormone (GnRH) analogues, aromatase inhibitors, sex steroids, glucocorticoids or any other medication that can influence response to GH therapy. Exception: Attention Deficit Hyperactive Disorder and its treatment can be included but should be recorded. * Any known or suspected clinically significant abnormality likely to affect growth or the ability to evaluate growth with standing height measurements, such as but not limited to: * Significant spinal abnormalities including but not limited to scoliosis, kyphosis and spina bifida variants. * Any other disorder that can cause short stature such as, but not limited to, psychiatric disorders, nutritional disorders, chronic systemic illness, chronic respiratory conditions (e.g. asthma), and chronic renal disease. * Turner Syndrome (including mosaicism). * Noonan Syndrome. * Born small for gestational age (defined as birth length below -2 SDS OR birth weight below -2 SDS OR both) (according to national standards). * Extreme prematurity, defined as gestational age less than 32 weeks. * Syndromic short stature defined by the presence of significant dysmorphic features and/OR major malformations, Laron syndrome, Prader-Willi syndrome, Russell-Silver syndrome. * Significant developmental delays, autism spectrum or intellectual deficit of any degree. * Skeletal dysplasia. * Magnetic resonance imaging (MRI) result confirming pituitary structural abnormalities. * Poor adherence to GH therapy or interruption of it for any time during the first year of therapy, as judged by the treating physician.