• Height [ Time Frame: every 4 months ] [ Designated as safety issue: No ]
  
• Growth velocity [ Time Frame: every 4 months ] [ Designated as safety issue: No ]
  
• Height at beginning of puberty [ Time Frame: At the biginning of puberty ] [ Designated as safety issue: No ]
  
• Final height [ Time Frame: When acheiving final height ] [ Designated as safety issue: No ]
  

• Psychological parameters [ Time Frame: once a year ] [ Designated as safety issue: No ]
  
• HbA1c and IGF-1 [ Time Frame: at baseline. after 3 months and than every 6 months ] [ Designated as safety issue: Yes ]
  

One arm, open prospective intervention study to assess biochemical markers of growth response to GH treatment in 20 children, aged 3-9 years old, with idiopathic short stature.

Objectives:

1. To determine axiological and biochemical markers for growth response
2. To assess the period of time necessary to determine the parameters which will differentiate between responders and non-responders

Inclusion criteria:

1. Ages 3 to <9 years
2. Short stature with height >2.25 SD below the mean
3. Prepubertal (Tanner stage I) at commencement of trial
4. Peak GH above 10ng/ml in at least one provocative test for GH secretion
5. Signing Informed consent forms

Exclusion criteria:

1. IUGR
2. Growth retardation associated with malignancy, severe chronic disease, genetic syndromes and endocrine disorders
3. Diabetes
4. Treatment with any medical product which may interfere with GH effects

Methods:

1. All participants will be treated with GH during the first year of the study (and then in accordance with the local ethic requirement, to supply drug which is not approved for the indication used in the study, for additional 3 years) and then will be followed up for the next 3 years.
2. The impact of GH therapy on clinical laboratory parameters that are indicative of the growth response will be assessed by collecting blood and urine samples during the 4 years study period.Samples will be test for biochemical markers of bone formation and resorption: bone alkaline phosphatase, osteocalcin, type I procollagen propeptide (PICP), hydroxyproline, pyridinoline, deoxypyridinoline, ICTP, TRAcP, GHL, NTX-I, BSP.
3. The primary endpoints are measurements of height and growth velocity during the year of GH treatment, the height at the beginning of puberty and final height. Secondary endpoints are psychological parameters, assessed by questionnaires.
4. Safety parameters are IGF1 and HbA1c, measured at baseline, 3 month and than every 6 months