OBJECTIVES:

I. Determine if mutations in the gene encoding the insulin-like growth factor-I receptor lead to relative insulin-like growth factor-I insensitivity and produce intrauterine growth retardation in children.

PROTOCOL OUTLINE:

Patients undergo blood draw. Insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) are measured. Patients whose IGF-I and IGFBP-3 levels are average or above are tested for the presence of mutation in the insulin-like growth factor-I receptor.

• Intrauterine growth retardation (IUGR), defined as birth weight less than 2 standard deviations below the mean by Usher and McLean Deficient "catch-up" growth (stature less than 5th percentile on growth chart after age 18 months) Normal or elevated circulating concentrations of insulin-like growth factor-I (IGF-I) and insulin-like growth factor binding protein-3 (IGFBP-3) IGF-I or IGFBP-3 within or above the 95th percentile confidence interval for age No other clinical explanation for poor prenatal and postnatal growth No IUGR due to maternal toxemia, endocrine disease, gastrointestinal disease, significant heart disease, or chromosomal abnormalities No other condition known to retard growth