title: Large-scale analysis of variation in the insulin-like growth factor family in humans reveals rare disease links and common polymorphisms.
abstract: The insulin-like growth factors IGF1 and IGF2 are closely related proteins that are essential for normal growth and development in humans and other species and play critical roles in many physiological and pathophysiological processes. IGF actions are mediated by transmembrane receptors and modulated by IGF-binding proteins. The importance of IGF actions in human physiology is strengthened by the rarity of inactivating mutations in their genes and by the devastating impact caused by such mutations on normal development and somatic growth. Large-scale genome sequencing has the potential to provide new insights into human variation and disease susceptibility. Toward this end, the availability of DNA sequence data from 60,706 people through the Exome Aggregation Consortium has prompted the analyses presented here. Results reveal a broad range of potential missense and other alterations in the coding regions of every IGF family gene, but the vast majority of predicted changes were uncommon. The total number of different alleles detected per gene in the population varied over an ∼15-fold range, from 57 forIGF1to 872 forIGF2R, although when corrected for protein length the rate ranged from 0.22 to 0.59 changes/codon among the 11 genes evaluated. Previously characterized disease-causing mutations inIGF2,IGF1R,IGF2R, orIGFALSall were found in the general population but with allele frequencies of <1:30,000. A few new highly prevalent amino acid polymorphisms were also identified. Collectively, these data provide a wealth of opportunities to understand the intricacies of IGF signaling and action in both physiological and pathological contexts.
authors.affiliation: From the Department of Biomedical Sciences, Paul L. Foster School of Medicine, Texas Tech Health University Health Sciences Center, El Paso, Texas 79905 peter.rotwein@ttuhsc.edu.
authors.forename: Peter
authors.identifier: 0000-0002-9505-1817
authors.initials: P
authors.lastname: Rotwein
mesh_terms: D000483:Alleles; D002352:Carrier Proteins / Q000235:genetics*; D059472:Exome; D005787:Gene Frequency; D006023:Glycoproteins / Q000235:genetics*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D007335:Insulin-Like Growth Factor II / Q000235:genetics*; D011110:Polymorphism, Genetic; D017526:Receptor, IGF Type 1; D017451:Receptors, Somatomedin / Q000235:genetics*
chemical_list: D002352:Carrier Proteins; D006023:Glycoproteins; C583557:IGF1 protein, human; C000597236:IGF1R protein, human; C035170:IGF2 protein, human; D017451:Receptors, Somatomedin; C075944:insulin-like growth factor binding protein, acid labile subunit; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II; D017526:Receptor, IGF Type 1
keywords: IGF binding proteins; IGF receptor; functional genomics; genomics; growth factor; human evolution; human variation; insulin; insulin-like growth factor (IGF); population genetics