Insulin-like Growth Factor 1 Genotypes Research Articles

Plasma Glial Cell-Derived Neurotrophic Factor and Insulin-like Growth Factor-1 Levels Were Not Correlated with the Severity of Age-Related Hearing Impairment in Humans.

The relationship between plasma glial cell-derived neurotrophic factor (GDNF) or insulin-like growth factor-1 (IGF-1) levels and age-related hearing impairment (ARHI) has not been reported in humans. By cross-sectional design, 268 subjects older than 33, with normal cognitive function and normal or symmetric sensorineural hearing loss, were selected randomly. Multivariate linear regression analysis was performed to test the impact of the plasma GDNF or IGF-1 level on the pure tone threshold of low frequencies (PTA-low) and high frequencies (PTA-high), respectively. Results showed that plasma GDNF and IGF-1 levels decreased with age without statistical significance. Multivariate linear regression analysis showed that GDNF or IGF-1 levels were not significantly correlated with PTA-low or PTA-high after adjusting age, gender, body mass index, systemic diseases, habits, and noise exposure. In conclusion, plasma GDNF or IGF-1 levels were not associated with the severity of ARHI in humans. However, these findings did not support the roles of GDNF or IGF-1 genotypes on hearing.

Role of IGF-1 in goat semen freezing: A Review

This review is based on the importance of Insulin-like Growth Factor-1 (IGF-1) in goat semen cryopreservation. Recent studies indicate that certain growth factors determine the seminal quality due to the interaction between seminal plasma and spermatozoa. Cryopreservation is the technique used to preserve semen at extremely low temperatures for extended periods, which is essential for artificial insemination (AI) and selective breeding programs. IGF-I promotes the proliferation and maturation of spermatozoa. IGF-I is involved in sperm motility, DNA fragmentation, membrane integrity and fertilizing capacity. There was a significant positive correlation between the weight of animals and IGF-1 genotype diversity. This review aims to investigate the effect of IGF-1 fortification in semen cryopreservation. Further, the review article also assesses the role of IGF-1 in improving the post-thaw quality and viability of goat semen, with the ultimate goal of enhancing the success rates of AI. The research gap this review aims to fill is the limited understanding of the role of IGF-1 fortification on goat semen cryopreservation.

Association of the Combined Effects between Insulin-Like Growth Factor-1 Gene Polymorphisms and Negative Life Events with Major Depressive Disorder among Chinese population in the Context of Oxidative Stress

Background Oxidative stress may be increased in a number of psychiatric disorders, including major depressive disorder (MDD). MDD has been shown to be related to insulin-like growth factor-1 (IGF-1) as well as to negative life events; exploring the interaction of IGF-1 polymorphisms and negative life events on the risk of MDD is needed. The aim of this study was to analyze the single and combined effects of IGF-1 polymorphisms (rs972936 and rs978458) and negative life events with MDD among Chinese population. Methods 420 MDD patients (according to DSM-V) and 420 age- and gender-matched control subjects were recruited in a case-control study. Negative life events were assessed using standard rating scales. IGF-1 rs972936 and rs978458 were identified by sequencing. The chi-square (χ2) tests were performed to explore the association of negative life events and IGF-1 polymorphisms with MDD. Results Our results found that the negative life events were associated with the risk of MDD (P < 0.001; OR = 3.28, 95% CI: 2.19-4.85). The genotypes of IGF-1 were associated with the risk of MDD (P < 0.001); carrying the IGF-1 rs972936 C allele (OR = 1.53, 95% CI: 1.26-1.85) and rs978458 T allele (OR = 1.92, 95% CI: 1.58-2.34) had a higher risk of MDD. The combined effects between IGF-1 rs978458 and negative life events were associated with the risk of MDD (P < 0.05; OR = 2.94, 95% CI: 1.23-7.03), but IGF-1 rs972936 was not associated (P > 0.05). Conclusions Based on the oxidative stress hypothesis, we confirm that carrying IGF-1 rs972936 C allele and rs978458 T allele have a higher risk of MDD and the combined effects between IGF-1 rs978458 and negative life events were associated with the risk of MDD among Chinese population.

A functional variant in the promoter region of IGF1 gene is associated with chicken abdominal fat deposition

Insulin-like growth factor 1 (IGF1) plays an important role in the regulation of cell growth, proliferation, differentiation, and apoptosis. Previously several studies revealed that genotypes of chicken IGF1 c.-366A > C were significantly associated with abdominal fat weight and body weight in chickens. But the underlying mechanism is still unknown. To investigate the mechanism underlying the association, herein, we performed IGF1 gene mRNA expression profiling, a dual-luciferase reporter assay and electrophoretic mobility shift assay (EMSA). Quantitative real-time PCR results showed that IGF1 gene was widely expressed in 14 tissues. The mRNA expression levels of IGF1 gene in both abdominal fat and jejunum were significantly higher in fat broilers than in lean broilers. However, the opposite results were observed in the pancreas. The reporter gene assay showed that the promoter luciferase activity of allele A was significantly higher than that of allele C (P < 0.05). In addition, the luciferase activity of allele A promoted by the transcription factor AP1 and OCT1 was higher than that of allele C (P < 0.05). Electrophoretic mobility shift assay result showed that allele A binding to the transcription factor AP1 and OCT1 was stronger than that of allele C. All in all, our data indicated that the IGF1 gene c.-366A > C is a functional SNP responsible for chicken adipose deposition.

The Insulin-like Growth Factor-1 (G>A) and 5,10-methylenetetrahydrofolate Reductase (C677T) Gene Variants and the Serum Levels of Insulin-like Growth Factor-1, Insulin, and Homeostasis Model Assessment in Patients with Acne Vulgaris.

Background & Objective:To find an association between gene variants of insulin-like growth factor-1 (IGF-1) and 5,10-methylenetetrahydrofolate reductase (MTHFR) with the risk of acne vulgaris (AV).Methods:In a case-control study, we investigated 150 AV patients and 148 healthy individuals (aged 18-25 years) for the IGF-1 G>A and MTHFR C677T polymorphisms, as well as the serum levels of IGF-1, insulin, and the homeostasis model assessment of insulin resistance (HOMA-IR). The serum biochemical parameters and the genotypes of IGF-1 G>A and MTHFR C677T were detected by using appropriate kits and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods, respectively.Results:The frequencies of IGF-1 and the MTHFR polymorphisms were not significantly different comparing patients and controls. The serum level of IGF-1 was 179.8±72.8 µg/L in AV patients compared to 164.6±63.7 µg/L in controls (P=0.056). The serum level of insulin in female patients was significantly higher than controls. The HOMA was 3.54±5.6 in patients compared to 1.16±1.4 (P<0.001) in controls. Significantly higher levels of fasting blood sugar (FBS), total cholesterol, and low-density lipoprotein-cholesterol (LDL-C) were detected in female patients than controls. However, the level of estradiol was significantly lower in female patients than in controls. In females, the presence of the MTHFR T allele was associated with significantly higher levels of FBS and LDL-C, as well as a significantly lower level of estradiol compared to those carriers of the C allele.Conclusion:We found the absence of an association between IGF-1 and MTHFR polymorphisms with the risk of AV. However, increased insulin, IGF-1, and HOMA levels in AV patients indicated the effect of insulin and insulin resistance in the risk of AV and its severity.

Effect of IGF-1 and GH Genes Polymorphism on Weights and Body Measurements of Awassi Lambs in Different Ages

The study was carried on 68 ewes of local Awassi sheep in the Al-Kafeel sheep station Karbala governorate, Iraq for the period from 1/10/2017 to 1/8/2018. Genetic analysis was carried out in the molecular genetics laboratory at the College of Agriculture / Basrah University in order to extract (DNA) and determine the genotype&nbsp; of the IGF-1(Insulin-like growth factor 1) and GH (Growth Hormone) genes. This study aimed to know the association between the genotype of the ewes of IGF-1 and GH&nbsp; genes and their relationship to the productive traits of the lambs, which included the weights of lambs from birth to weaning and body measurements, Three of the&nbsp; genotypes for IGF-1 were revealed AG, GC, CC and two for GH CT, TC . The effect of IGF-1 genotypes was significant (P

Effect of IGF-1 and GH Genes Polymorphism on Weights and Body Measurements of Awassi Lambs in Different Ages

The study was carried on 68 ewes of local Awassi sheep in the Al-Kafeel sheep station Karbala governorate, Iraq for the period from 1/10/2017 to 1/8/2018. Genetic analysis was carried out in the molecular genetics laboratory at the College of Agriculture / Basrah University in order to extract (DNA) and determine the genotype of the IGF-1(Insulin-like growth factor 1) and GH (Growth Hormone) genes. This study aimed to know the association between the genotype of the ewes of IGF-1 and GH genes and their relationship to the productive traits of the lambs, which included the weights of lambs from birth to weaning and body measurements, Three of the genotypes for IGF-1 were revealed AG, GC, CC and two for GH CT, TC . The effect of IGF-1 genotypes was significant (P&lt;0.05) on weights of lambs at weaning, age 6 months and some body measurements with superior genotype GC. The genotypes of GH had a significant effect on the weight of the lambs at birth by CT superiority. While the weights of weaning, six months and body measurements were not significantly affected by different genotypes.

Association of IGF-I gene polymorphism with diabetic nephropathy in Egyptians with type 2 diabetes

BackgroundGenetic-based studies are being carried out worldwide to identify the susceptibility genes for diabetic nephropathy (DN), which represents a major health problem in all diabetics.AimTo study the association between genotypes of insulin-like growth factor-1 (IGF-1) and DN among Egyptian patients with type 2 diabetes and if there is any possible relation between these polymorphisms and different variables.Patients and methodsA total of 26 diabetics without nephropathy (group 1) and 26 with nephropathy (group 2), with an average age of 52.7±6.1 years, and 25 age-matched and sex-matched healthy participants (control group) were included. Two tagging single nucleotide polymorphisms were assessed in IGF-1 gene: rs6214 and rs10860860. Genotypic distribution was tested for Hardy–Weinberg equilibrium. The genotype was evaluated using the χ2 tests. Fasting blood glucose, glycated hemoglobin, uric acid, lipid profile, serum creatinine, and urine albumin–creatinine ratio were assessed.ResultsThe distribution of IGF-1 gene polymorphisms reflects a significant association with DN, where the frequency of variant genotype GG in polymorphism rs6214 was found to be significantly higher in diabetics with nephropathy than other groups [odds ratio (OR)=20.57; 95% confidence interval, 2.25–74; P=0.001). Moreover, the frequency of variant AA in polymorphism rs10860860 was also found to be significantly higher in diabetics with nephropathy (OR=7.37; 95% confidence interval, 1.87–30.07; P=0.001). However, GA and AT alleles were found to be associated with ORs less than 1 in diabetics with nephropathy when compared with other groups (P=0.002 and 0.007, respectively), which means that it could be significantly protective against DN. where they found to be significantly higher in diabetics with genotype GG than those with genotype GA (P=0.13, 0.11 respectively).ConclusionThe variants of IGF-1 rs6214 and rs10860860 could entail a risk of DN in Egyptians with type 2 diabetes mellitus. It means that the type of IGF-1 gene polymorphism is responsible for the susceptibility of DN more than its serum level.

Dietary Acid Load, IGF-1 Single Nucleotide Polymorphism and Bone Resorption among Postmenopausal Chinese Women

The interaction of dietary and genetic factors may affect the development of bone deterioration. This study investigated whether the effects of dietary acid load (DAL) on bone loss in postmenopausal Chinese women were moderated by the insulin-like growth factor-1 (IGF-1) single nucleotide polymorphism, a known gene that plays a role in the regulation of bone formation and bone remodeling. A total of 217 healthy participants were recruited from the National Council of Senior Citizens Organizations Malaysia. Serum collagen type 1 cross-linked C-telopeptide was used as a surrogate bone marker to assess bone resorption and Agena® MassARRAY genotyping analysis was used to identify the signaling of IGF-1 rs35767. The dietary acid load was measured by potential renal acid load score while physical activity was ascertained using the Global Physical Activity Questionnaire. Hierarchical regression was applied to test the main and interaction effects of DAL and IGF-1 genotypes in bone resorption. The result supported the diet-dependent acid-base balance theory that higher DAL was positively associated with bone resorption (β = 0.152, p = 0.031, F(6,207) = 2.11, sig-F = 0.036, R2 = 0.079). However, the results indicated that there was no significant correlation between IGF-1 and bone resorption, or any significant interaction between DAL and IGF-1. In conclusion, there was no moderating effect of IGF-1 on the relationship between DAL and bone resorption.

Association of Insulin-Like Growth Factor-1 Gene Polymorphisms with Different Types of Myopia in Egyptian Patients.

To investigate the effect of the insulin-like growth factor-1 (IGF-1) gene's rs6214 and rs5742632 polymorphisms on IGF-1 expression levels and their association with different types of myopia in Egyptian patients. A case-control format was used that included 272 patients with myopia and 136 controls. The IGF-1 gene rs6214 and rs5742632 polymorphisms were genotyped using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analyses. IGF-1 levels were measured by an enzyme-linked immunosorbent assay. In patients with high-grade myopia, the frequencies of the IGF-1 rs6214 GA and AA genotypes, and the A allele were significantly increased compared to the control group: 41.9% vs. 33.8%, 17.7% vs. 8.9%, and 38.9% vs. 25.7%, respectively. Subjects with the GA and AA genotypes and carriers of A allele were significantly more likely to have high-grade myopia: odds ratios (OR) = 1.75, 95% confidence interval (CI) = 1.03-2.9, and p = 0.03; OR = 2.8, 95% CI = 1.3-6.0, and p = 0.003; and OR = 1.8, 95% CI = 1.25-2.61, and p = 0.001, respectively. A nonsignificant association of the IGF-1 gene rs5742632 polymorphism with the two myopia groups was also observed. The IGF-1 levels were significantly increased in patients with high-grade myopia and simple myopia compared to the control group (p < 0.05). In addition, our results showed a nonsignificant association of the IGF-1 (rs6214-rs5742632) haplotype with either simple myopia or high-grade myopia. We found a significant association of the IGF-1 gene rs6214 polymorphism in Egyptian patients with simple myopia and high-grade myopia. IGF-1 levels were significantly increased in relation to the IGF-1 rs6214 genotypes, while a nonsignificant association was found between IGF-1 level and the IGF-1 (rs5742632) genotypes.

Genetic polymorphisms of insulin-like growth factor 1 and insulin-like growth factor binding protein 3, xenoestrogen, phytoestrogen, and premenopausal breast cancer.

Previous studies suggest a combined effect of insulin-like growth factor 1 (igf-1) and igf binding protein 3 (igfbp-3) gene polymorphisms, xenoestrogen, and phytoestrogen on the igf-1 signalling pathway and serum concentrations in the igf system, which are associated with premenopausal breast cancer (bca) risk. Between 2010 and 2012, our study recruited 140 premenopausal bca patients and 160 community-based premenopausal control subjects. Participants were surveyed about oral contraceptive (oc) use, dietary habits, and other bca risk factors. TaqMan assays were used to determine igf-1 rs1520220 and igfbp-3 rs2854744 genotypes. Daily intakes of energy-adjusted soy isoflavones (easis) were calculated by the residual method. Multivariate logistic regression was applied to estimate the adjusted odds ratios (ors) and 95% confidence intervals (cis) of the igf-1 rs1520220 and igfbp-3 rs2854744 genotypes, oc use, and intake of easis. Stratified analyses were performed to detect the gene-environment combined effect, and multivariate logistic regression was used to estimate interaction coefficients (iors) by the multiplicative model, with 95% cis. The delta method was used to calculate interaction coefficients by the additive model [relative excess risk of interaction (reri), attributable proportions of interaction (apis)] and 95% cis. The igf-1 and igfbp-3 genotypes, oc use, and easis were not found to be associated with bca risk (p > 0.05). Stratified analysis showed that the risk of bca was markedly increased in women carrying the igfbp-3C allele and using ocs compared with women either carrying the igfbp-3C allele or using ocs (or: 3.02; 95% ci: 1.04 to 8.79). The interaction coefficients ior, reri, and api were 4.89 (95% ci: 1.09 to 21.90), 2.42 (95% ci: -0.76 to 5.61), and 0.80 (95% ci: 0.46 to 1.67) respectively. The igfbp-3 rs2854744 polymorphism and oc use might synergistically increase premenopausal bca risk.

Effects of IGF-1 genotype on weight gain and body shape in GIFT strain Oreochromis niloticus

Insulin-like Growth Factor 1(IGF-1) is one of important genes controlling growth and development in animals.By comparing with exon1-partial intron 2-exon 3-partial intron 4 sequences of IGF-1 from six indi-viduals of Genetically Improved Farmed Tilapia(GIFT) strain,we identified three SNPs on IGF-1 in this study,including intron1_A1307G,intron1_G1319T and intron3_C6T.PCR-RFLP was performed in intron1_A1307G and intron3_C6T genotypes detection on 121 individuals from five families of GIFT strain.The results of correlation analysis showed that intron1_A1307G was significantly associated with female fish weight gain and the ratio of body thickness/length(P0.05).The weight gain and thickness/length ratio of female fish with AA genotype were significantly higher than those of female fish with GG type(P0.05).However,the correlation of genotypes with those traits in male fish was not significant(P0.05).Intron3_C6T was significantly associated with weight gain in both male(P0.05) and female(P0.01).The weight gain of male fish with TT and CT genotype was significantly higher than that of male fish with CC type,while the weight gain of female with CT genotypes was significantly higher than that of female fish with TT.Intron3_C6T was also significantly associated with height/length ra-tio(P0.05) in female fish.The height/length ratio of female fish with TT and CT genotypes was significantly higher than that with CC(P0.05).In order to verify the performance of the screened markers in other families,we detected the correlation between intron1_A1307G,intron3_C6T genotypes and weight gain among 417 individuals from 60 families of GIFT strain(averaging seven individuals per family),and similar results were observed.The diverse genetic background and smaller size of samples resulted in the decreased correlation significance.These results showed that genetic background and sample size should be considered during molecular maker screening.And the two molecular markers of intron1_A1307G,intron3_C6T identified in this study could be used as refer-ence in GIFT strain breeding.

Insulin-like growth factor-1 genotypes and haplotypes influence the survival of prostate cancer patients with bone metastasis at initial diagnosis

BackgroundThe insulin-like growth factor-1 (IGF-1) plays an important role in growth of prostate cancer (PCa) cells and facilitating the development and progression of PCa. This study aimed to evaluate the association of polymorphisms in three linkage disequilibrium (LD) blocks of the IGF-1 on the survival of metastatic PCa patients.MethodsA total of 215 patients with bone metastases at initial presentation were included in this study. The cytosine-adenine (CA) repeat polymorphism and rs12423791 were selected as representative polymorphisms in the LD blocks 1 and 2, respectively. Haplotype in the LD block 3 was analyzed using two tag single nucleotide polymorphisms (SNPs), rs6220 and rs7136446. Cancer-specific survival rate was estimated from the Kaplan-Meier curve, and the survival data were compared using the log-rank test.ResultsCancer-specific survival was significantly associated with the CA repeat polymorphism, rs12423791, and rs6220 (P = 0.013, 0.014, and 0.014, respectively). Although rs7136446 had no significant association with survival, the haplotype in the LD block 3 was significantly associated with cancer-specific survival (P = 0.0003). When the sum of the risk genetic factors in each LD block (19-repeat allele, C allele of rs12423791, or C-T haplotype) was considered, patients with all the risk factors had significantly shorter cancer specific-survival than those with 0–2 risk factors (P = 0.0003).ConclusionsPolymorphisms in the IGF-1, especially a haplotype in the LD block 3, are assumed to be genetic markers predicting the outcome of metastatic PCa.

Association study of IGF1 polymorphisms with susceptibility to high myopia in a Japanese population

PurposePolymorphisms in the insulin-like growth factor 1 (IGF1) gene were previously associated with high or extreme myopia in Caucasian and Chinese populations. In the present study, we investigated whether IGF1 polymorphisms are associated with high myopia in a Japanese population.MethodsA total of 446 Japanese patients with high myopia (≤−9.00 diopters) and 481 Japanese healthy controls (+1.50 diopters to −1.50 diopters) were recruited. We genotyped seven tagging single-nucleotide polymorphisms (SNPs) in IGF1 and assessed allelic and haplotypic diversity in cases and controls.ResultsThere were no statistically significant differences in the allele frequencies of IGF1 SNPs and genotypes between cases and controls (P>0.05). However, the A allele of rs5742629 and the G allele of rs12423791 were associated with a moderately increased risk of high myopia (odds ratio [OR] =1.20 and OR =1.21, respectively) with borderline statistical significance (P=0.0502, corrected P (Pc) =0.21 and P=0.064, Pc=0.29, respectively). The haplotype consisting of the A allele of rs5742629 and the G allele of rs12423791 was marginally associated with the risk of high myopia (P=0.041; OR =1.21); this association was not significant after correction (Pc=0.19).ConclusionWe found that the IGF1 SNPs are not significantly associated with high myopia in our Japanese population. Our results are in contrast to a previous study in which extreme myopia cases had significantly higher frequencies of the G allele of rs5742629 and the C allele of rs12423791 than controls. Therefore, the IGF1 SNPs may not be important factors for susceptibility to high myopia in all populations. Further genetic studies are needed to elucidate the possible contributions of the IGF1 region to the development of high myopia.

Insulin-like growth factor 1 gene polymorphism and breast cancer risk among arab omani women: a case-control study.

Breast cancer is the most common cancer worldwide with significant global burden. Insulin-like growth factor 1 (IGF1) is an important regulator of cellular growth, differentiation, and apoptosis and mitogenic and antiapoptotic activities. Some studies suggested an association between cytosine adenine (CA) repeats gene polymorphisms of IGF1 and the risk of developing breast cancer while other studies did not find such an association. This study aims investigate the role of IGF1 (CA) repeats gene polymorphisms in the risk of developing breast cancer among Omani women.MethodsWe analyzed (CA) repeats gene polymorphisms of IGF1 by extraction of genomic DNA from the peripheral blood of 147 patients with breast cancer and 134 control participants and performed genotyping using DNA sequencing.ResultsApproximately 46% of patients carried the IGF (CA)19 repeat allele, with 31.3% carrying two copies of this allele and 50% of controls carried the IGF (CA)19 repeat allele with 30.1% carrying two copies of this allele. The difference of the IGF CA repeat groups was significant between cases and controls with (P =0.02). In contrast, there was no difference in the distribution of (CA)19 repeat allele, (CA)18 repeat allele and (CA)19 repeat allele between cases and controls. The difference of the CA groups was significant between cases and controls among postmenopausal women with (P =0.026), whereas no difference was observed among postmenopausal subjects (P =0.429). In both pre- and postmenopausal groups there was no difference in the distribution of (CA)19 repeat allele, (CA)18 repeat allele and (CA)20 repeat allele between patients and control subjects. On further IGF1 genotypes classification, we found an association between progesterone receptor status and the genotypes group where the non carrier of (CA)19 repeat group was compared to (CA)19 repeat carrier group (OR =2.482; 95% CI =1.119–5.503; P value =0.023).ConclusionOverall there was no association between the IGF (CA)19 repeat and breast cancer in Omani females.

Does insulin-like growth factor 1 genotype influence muscle power response to strength training in older men and women?

The CA-repeat polymorphism in the insulin-like growth factor 1 (IGF1) gene promoter region has been associated with strength and circulating IGF-I protein levels. The purpose of the study was to determine if the IGF1 CA-repeat polymorphism influences muscle power at baseline and in response to ST in older adults. Knee extensor peak power (PP) was measured at 50, 60, and 70% of 1-RM strength before and after 10 weeks of unilateral knee extensor ST in older adults, aged 50-85 years, to determine the changes in absolute and relative PP with ST. Subjects (N = 114) were genotyped for the IGF1 CA-repeat polymorphism and grouped as homozygous for the 192 allele, heterozygous, or non-carriers of the 192 allele. The 192 homozygotes had significantly lower baseline PP at 50, 60, and 70% of 1-RM strength than the non-carriers when age, sex, and baseline fat-free mass were covaried (all P < 0.05). This same relationship was observed when the highest PP within these ranges was compared (e.g., 317.6 ± 13.5 for 192 homozygotes and 380.2 ± 16.3 for non-carriers of the 192 allele, P < 0.05). Both absolute and relative PP increased significantly with ST in all genotype groups as expected, but there were no significant relationships among IGF1 genotypes and any of the PP changes. Despite a significant relationship between IGF1 genotype and knee extensor peak power at baseline, IGF1 genotype does not appear to influence changes in knee extensor peak power with ST.

Evaluation of the insulin-like growth factors (IGF) IGF-I and IGF binding protein 3 in patients at high risk for breast cancer

Our data suggest that serum concentrations of insulin-like growth factor I and insulin-like growth factor binding protein 3 do not correlate with breast cancer development.

Insulin VNTR and IGF-1 Promoter Region Polymorphisms Are Not Associated with Body Composition in Early Childhood: The Generation R Study

Objective: The objective of this study was to examine the associations between insulin gene variable number of tandem repeats (INS VNTR) and insulin-like growth factor 1 (IGF1) gene promoter region polymorphisms with body composition in early childhood. Methods: This study was embedded in an ongoing prospective cohort study. Growth in early childhood (body mass index, total subcutaneous fat mass and waist-hip ratio) was assessed at birth and at the ages of 6 weeks and 24 months. DNA for genotyping was available in 738 children. Results: The genotype distribution of the INS VNTR gene was I/I 50.4%, I/III 40.4%, and III/III 9.2%. IGF1 genotypes were categorized in the following categories based on their 192-bp allele: homozygous (wild-type) 43.1%, heterozygous 45.8%, and noncarrier 11.2%. No differences were found in body mass index, total subcutaneous fat mass and waist-hip ratio in early childhood between the three groups for both the INS VNTR and IGF1 genotypes. We also did not find interactions between these genotypes and gender or birth weight on the effects of body composition measures. Conclusions: Our results do not support previous studies showing associations between INS VNTR and IGF1 promoter region polymorphisms with body composition in early childhood.

Association of an insulin‐like growth factor 1 gene microsatellite with phenotypic variation and estimated breeding values of growth traits in Canchim cattle

A population of 1398 Canchim (CA) cattle was genotyped to assess the association of an insulin-like growth factor 1 (IGF1) gene microsatellite with phenotypic variation and estimated breeding values of pre-weaning, weaning and post-weaning growth traits. After an initial analysis, the IGF1 genotype only had a significant effect (P < 0.05) on birth weight (BW) and weaning weight adjusted to 240 days (WW240). For these two traits, direct and maternal breeding values were estimated using the restricted maximum likelihood (reml). Two analyses were carried out. In the first (Model I), all fixed effects were fitted. In the second (Model II), the fixed effect of the IGF1 genotype was omitted. The estimated genetic and phenotypic components of variance were similar for every trait in both models. For Model I, estimated direct and maternal heritabilities were 0.26 and 0.16 for BW and 0.23 and 0.14 for WW240 respectively. The genetic and phenotypic correlations between BW and WW240 were 0.38 and 0.38 (Model I) and 0.19 and 0.38 (Model II) respectively. Fifty animals were classified according to their direct and maternal breeding values for both traits. Spearman rank-order correlation between animal rankings in the two models was used to assess the effect of including the IGF1 genotype in the model. Non-significant values from this correlation were indicative of a difference in breeding value rankings between the two approaches. The IGF1 gene was found to be associated with phenotypic variation and breeding values in the early phase of growth.

Insulin-like growth factor-1 promoter polymorphisms and colorectal cancer: a functional genomics approach

Rationale:Insulin-like growth factor-1 (IGF1) has been proposed to mediate the obesity-related carcinogenic effects of “Western lifestyle”. While genetic factors explain at least half of inter-individual IGF1 variation, the IGF1 polymorphisms...