Insulin-Like Growth Factor I

Alternative Names

IGF-1
IGF I
Somatomedin C

Associated Diseases

Rheumatoid Arthritis

Back to search Result

OMIM Number

147440

Gene Map Locus

12q23.2

Description

The IGF1 gene encodes a protein of 195 amino acids that is a member of the insulin-like growth factor (IGF) family of proteins. Other proteins that belong to this family include IGF1 and IGF2, the receptors IGF1R and IGF2R, and several IGF-binding proteins (IGFBP1-7). The function and structure of IGF-I is similar to insulin. It mediates the growth-promoting activities of growth hormone. IGF-I binds the IGF1R homodimers and activates them, which mediate pre- and postnatal growth. About 75% of circulating IGF1 in the bloodstream is produced in the liver.

Molecular Genetics

IGF1 gene was mapped to chromosome 12q23.2. It consists of five coding exons and is about 85 kb in length. Mutations in this gene are the cause of Insulin-like Growth Factor I Deficiency, characterized by growth retardation, sensorineural deafness and mental retardation. Some studies suggested that (CA) repeat polymorphism in the promoter region of IGF-I may be associated with risk of breast cancer. Also a positive relation was found between circulating IGF1 concentrations and the risk of breast cancer in premenopausal, but not postmenopausal women.

Epidemiology in the Arab World

View Map

Other Reports

Kuwait

Dhanusi et al. (2012) investigated the association of a 192 bp CA repeat polymorphism in the IGF-I gene with Rheumatoid Arthritis. This study utilized 52 healthy controls and 68 RA patients, 97% of whom were found to carry the wild-type allele. All controls carried the wild-type allele. Of the small proportion of samples that carried the variant, all were Arab and had RA. Significantly more male patients (14%) carried the variant when compared to female patients (2%). In addition, RA patients had significantly lower levels of plasma IGF-I.

Oman

Al-Ajmi et al. (2012) investigated the association between IGF1 (CA) repeats gene polymorphisms and the risk of developing breast cancer in 147 Omani women with breast cancer and 134 female control participants. The (CA) repeats ranged from (CA)10 to (CA)22. Using fragment analysis and sequencing for the (CA) repeats, the results showed that the (CA)19 allele was the highest among Omanis accounting for approximately 46% (carrying one copy) and 31% (carrying two copies) in the cases. While in the controls it was 51% (carrying one) and 30% (carrying the two copies). It was found that there is no association between IGF1 (CA) repeats and breast cancer in Omani females.

External Links

http://ghr.nlm.nih.gov/gene/IGF1 http://www.genecards.org/cgi-bin/carddisp.pl?gene=IGF1 http://www.ncbi.nlm.nih.gov/gene/3479

Contributors

Pratibha Nair: 09.07.2013
Nada Assaf: 01.07.2013

Edit History

Pratibha Nair: 04.08.2013