Status of Growth Hormone/ Insulin-like Growth Factor-1 (GH/IGF-1) Axis and Growth Failure in Ataxia Telangiectasia (AT)

Inclusion Criteria: * Have a diagnosis of AT * Have no fusion of epiphyses/closed growth plates as determined by X-ray of left wrist and hand (special skeletal age film) * Be between 3 years to 18 years old and have not completed puberty * Consent to permit blood and/or tissue samples for storage * Demonstrate growth failure: height below the 10th percentile for chronological age * Have a primary care physician at home * Demonstrate growth failure, defined as growth velocity (measured as linear growth) that is less than 5% to 10% of that expected for children of the same age group, over the past 12 months * Willingness to remain hospitalized for several days * Provide evidence of serum IGF-1 level performed within the preceding 6 months and the results fall below 25% range of normal limits for age Exclusion Criteria: * Have fusion of epiphyseal plates * Be under the age of 3 years or have reached completion of puberty * Have a serum IGF-1 level that is above the 25% range of normal limits for age * Be above the 10th percentile height for chronological age * Demonstrate any history of anaphylactic reaction or hypersensitivity to one of the GH formulation * Have any active or suspected neoplasia * Demonstrate signs of intracranial hypertension as evidenced by papilledema upon examination by fundoscopy * Have any condition that, in the investigator's opinion, places the patient at undue risk by participating in the study * Be unwilling to undergo testing or procedures associa…