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Insulin-like growth factor I gene deletion causing intrauterine growth retardation and severe short stature
K A Woods1, C Camacho-Hübner, D Barter
1University Department of Paediatrics, John Radcliffe Hospital, Oxford, UK.
Insights
A rare genetic condition in a 15-year-old boy revealed a complete disruption of the insulin-like growth factor I (IGF-I) gene. This finding highlights IGF-I
Area of Science:
- Human Genetics
- Endocrinology
- Developmental Biology
Background:
- Insulin-like Growth Factor I (IGF-I) plays a crucial role in growth and development.
- Molecular defects in the IGF-I gene can lead to various growth and developmental disorders.
- Understanding the complete impact of IGF-I gene disruption is essential for comprehending its physiological functions.
Observation:
- A 15-year-old boy from a consanguineous family presented with severe intrauterine growth failure, sensorineural deafness, and mild mental retardation.
- Endocrine evaluation showed elevated growth hormone (GH) with undetectable serum IGF-I levels.
- Genetic analysis identified a homozygous partial deletion in the IGF-I gene, resulting in a truncated mature IGF-I peptide.
Findings:
- This case represents the first human instance of a homozygous molecular defect in the IGF-I gene.
- The patient's condition demonstrates that complete disruption of the IGF-I gene is compatible with life.
- The findings indicate a significant role of IGF-I in human fetal growth and development.
Implications:
- The study underscores the critical role of IGF-I in prenatal and postnatal growth.
- Neurological abnormalities observed in the patient suggest a potential involvement of IGF-I in central nervous system development.
- This research provides valuable insights into the genetic basis of growth disorders and potential therapeutic targets.
Abstract:
The first human case of a homozygous molecular defect in the gene encoding insulin-like growth factor I (IGF-I) is described. The patient was a 15-year-old boy from a consanguineous pedigree who presented with severe intrauterine growth failure, sensorineural deafness and mild mental retardation. Endocrine evaluation of the growth hormone (GH)--IGF-I axis revealed elevated GH secretion, undetectable serum IGF-I and normal serum IGF-binding protein-3, acid-labile subunit, and GH-binding activity. Analysis of the IGF-I gene revealed a homozygous partial IGF-I gene deletion involving exons 4 and 5, which encodes a severely truncated mature IGF-I peptide. This patient demonstrates that complete disruption of the IGF-I gene in man is compatible with life, and indicates a major role for IGF-I in human fetal growth. In addition, his neurological abnormalities suggest that IGF-I may be involved in central nervous system development.