Insulin-like growth factor-I deficiency in children with growth hormone insensitivity: current and future treatment options

Characterization of Primary IGF-1 Deficiency in a Cohort of Canadian Children with Short Stature Using a Novel Algorithm Tailored to Electronic Medical Records

(1) Background: Severe primary insulin-like growth factor-I deficiency (SPIGFD) is a rare disorder causing short stature in children due to low insulin-like growth factor 1 (IGF-1) levels. Given the sparsity of reported cases of SPIGFD worldwide, the condition may be underdiagnosed, potentially preventing affected children from receiving therapy with recombinant human IGF-1 (rhIGF-1). Our objective was to determine the prevalence of SPIGFD among children with short stature at a large pediatric tertiary care center through the use of a novel electronic medical record (EMR) algorithm. (2) Methods: We queried our EMR using an algorithm that detected all children seen at our center between 1 November 2013 and 31 August 2021 with short stature and low IGF-1. We then conducted chart reviews, applying established diagnostic criteria for those identified with potential SPIGFD. (3) Results: From a cohort of 4863 children with short stature, our algorithm identified 30 (0.6%) patients with potential SPIGFD. Using chart reviews, we determined that none of these patients had SPIGFD. (4) Conclusions: Our algorithm can be used in other EMRs to identify which patients are likely to have SPIGFD and thus benefit from treatment with rhIGF-1. This model can be replicated for other rare diseases.

Detection of synthetic analogues of insulin-like growth factor 1 in different biological fluids by liquid chromatography quadrupole time-of-flight mass spectrometry: comparison of different immunoaffinity protocols

Insulin-like growth factor 1 analogues are prohibited in sport for their ability to enhance athletic performance in several sport disciplines. Their detection presents several analytical challenges, mainly due to the minimum required performance limits fixed by the World Anti-Doping Agency. Here, we are presenting analytical workflows to detect IGF-1 and its analogues in different biological matrices. Several off-line immunocapture techniques and protocols were comparatively evaluated. Separation and detection were performed by using standard flow reverse-phase liquid chromatography coupled to a time-of-flight mass spectrometer. The best recoveries were obtained using magnetic beads or pipette tips functionalized with protein A. The analytical workflows were fully validated for qualitative determinations: all the target analytes were clearly distinguishable from the interference of the matrices, with limits of detection and identification in the range of 0.05-0.30 ng/mL in urine and 0.5-2.0 ng/mL in serum/plasma. The extraction efficiency proved to be repeatable (CV% < 10) with recoveries higher than 50%. Intra- and inter-day precision were found to be smaller than 10 and 15%, respectively. The method was successfully applied to the analysis of authentic matrix samples containing the target peptides at the minimum required performance limits, proving that the method developed can be successfully applied to detect and identify IGF-1 analogues for doping control purposes in all the matrices selected. The analytical workflow developed here to detect the target peptides in different matrices can be readily implemented in anti-doping laboratories and has the potential to be adapted for the simultaneous analysis of different similarly sized peptide hormones of doping relevance.

Detection of LongR3 -IGF-I, Des(1-3)-IGF-I, and R3 -IGF-I using immunopurification and high resolution mass spectrometry for antidoping purposes

Insulin-like growth factor-I (IGF-I) and its analogs LongR³ -IGF-I, Des(1-3)-IGF-I, and R³ -IGF-I are prohibited substances in sport. Although they were never approved for use in humans, they are readily available as black market products for bodybuilding and can be used to enhance physical performance. This study's aims were to validate a fast and sensitive detection method for IGF-I analogs and to evaluate their detectability after intramuscular administration in rats. The sample preparation consisted of an immunopurification on MSIA™ microcolumns using a polyclonal anti-human-IGF-I antibody. The target substances were then directly analyzed by nano-liquid chromatography coupled with high-resolution mass spectrometry. Abundant signs of lower quality, oxidized peptide forms were found in black market products, justifying the need to monitor at least both the native and mono-oxidized forms. The analytical performance of this method (linearity, carry over, detection limits, precision, specificity, recovery, and matrix effect) was studied by spiking the analogs into human serum. Following a single intramuscular administration (100 μg/kg) in rats, detection was evaluated up to 36 h after injection. While unchanged Des(1-3)-IGF-I and R³ -IGF-I were detected until 24 h after administration, LongR³ -IGF-I disappeared rapidly after 4 h. Des(1)-LongR³ -IGF-I, a new N-terminal Long-R³ -IGF-I degradation product, was detected in addition to Des(1-10)-LongR³ -IGF-I and Des(1-11)-LongR^3- IGF-I: the latter was detected up to 16 h. The same products were found after in vitro incubation of the analogs in human whole blood, suggesting that observations in rats may be extrapolated to humans and that the validated method may be applicable to antidoping testing.

Insulin-Like Growth Factor-1 (IGF-1) and Its Monitoring in Medical Diagnostic and in Sports

Insulin-like growth factor-1 (IGF-1) is the principal mediator of growth hormone (GH), plays a crucial role in promoting cell growth and differentiation in childhood and continues to have an anabolic effect in adults. IGF-1 is part of a wide network of growth factors, receptors and binding proteins involved in mediating cellular proliferation, differentiation and apoptosis. Bioavailability of IGF-1 is affected by insulin-like growth factor binding proteins (IGFBPs) which bind IGF-1 in circulation with an affinity equal to or greater than that of the IGF-1 receptor (IGF-1R). The six IGFBPs serve as carrier proteins and bind approximately 98% of all circulating IGF-1. Other proteins known to bind IGF-1 include ten IGFBP-related proteins (IGFBP-rPs), albeit with lower affinities than the IGFBPs. IGF-1 expression levels vary in a number of clinical conditions suggesting it has the potential to provide crucial information as to the state of an individual’s health. IGF-1 is also a popular doping agent in sport and has featured in many high-profile doping cases in recent years. However, the existence of IGFBPs significantly reduces the levels of immunoreactive IGF-1 in samples, requiring multiple pre-treatment steps that reduce reproducibility and complicates interpretation of IGF-1 assay results. Here we provide an overview of the IGF network of growth factors, their receptors and the entirety of the extended family of IGFBPs, IGFBP-rPs, E peptides as well as recombinant IGF-1 and their derivatives. We also discuss issues related to the detection and quantification of bioavailable IGF-1.

Relationship between the short stature and the prevalence of metabolic syndrome and insulin resistance markers in workers of a private educational institution in Peru

BACKGROUND AND AIMS

Short stature has been linked with the development of metabolic syndrome (MetS). However, only one study has been conducted in Latin American adults. We aimed to assess the association between short stature and MetS in workers of a private educational institution in Peru. In addition, we evaluated the association between height and surrogate markers of insulin resistance (IR).

METHODS

We performed an analytical cross-sectional study. We categorized the height in tertiles and evaluated MetS according to the Latin American Diabetes Association statement. We used the triglycerides and glucose (TyG) index and the triglycerides to HDL-cholesterol (TG/HDL-c) ratio as IR markers. We elaborated crude and adjusted Poisson generalized linear models to evaluate the association between height tertiles and MetS. For the IR markers, we carried out crude and adjusted linear regressions.

RESULTS

We analyzed 1080 participants and the overall prevalence of MetS was 16.2%. In the adjusted Poisson generalized linear model, using the high tertile as a reference, we found statistically significant differences in the prevalence of MetS with the low and intermediate tertile (aPR = 2.03; 95%CI: 1.48-2.77 and aPR = 1.41; 95%CI: 1.01-1.99; respectively). In the gender-stratified analysis, we found statistical significance between height and MetS when comparing high and low tertile for both genders. For IR markers, we found an inverse association between the height and TyG index (aβ = -0.14; 95%CI: 0.19 to -0.10) and TG/HDL-c ratio (aβ = -0.62; 95%CI: 0.84 to -0.39). When we stratified by gender, the association for both secondary outcomes and height remained statistically significant in both groups.

CONCLUSIONS

We found an association between short stature and the prevalence of MetS and IR markers. We need studies with national representative samples to define the threshold of short stature with better sensitivity and specificity for the screening of MetS.

Efficient process development for high-level production, purification, formulation, and characterization of recombinant mecasermin in Escherichia coli

Overproduction of recombinant mecasermin was achieved by investigation of effect of three factors, temperature, inducer amount, and culture media, at three levels according to the Taguchi statistical design in Escherichia coli in a bench-scale bioreactor. In optimal conditions (induction temperature 28 °C, terrific broth with glucose (TB+G) medium, with 0.1 mM IPTG as inducer) 0.84 g/L mecasermin with expression levels of 38% of total protein and 4.13 g/L final dry cell biomass was produced, that is one of the highest values of recombinant protein has been reported in the batch system. The cell disruption was done by lysozyme pretreatment with sonication to the efficient purification of mecasermin. The isolated and washed inclusion bodies were solubilized in Gdn-HCl at pH 5.4 and folded with glutathione and purified with gel filtration. The purified rhIGF-1 (mecasermin) was formulated with arginine. Mecasermin protein remained t stable at 4 °C for up to 2 years. The quantitative and qualitative control indicated that mecasermin is expressed correctly (without the initial methionine by mass spectrometry), pure (without endotoxin and other protein impurities), correct folding (FTIR, RF-HPLC), monomer form (SEC-HPLC), and active (bioactivity test). Also, the purification results revealed that expression at low temperature results in the efficient purification of the overproduced mecasermin with high quantity and quality.

IGF-1 reverses the osteogenic inhibitory effect of dexamethasone on BMP9-induced osteogenic differentiation in mouse embryonic fibroblasts via PI3K/AKT/COX-2 pathway

Glucocorticoid-Induced Osteoporosis (GIOP) is a prevalent clinical complication caused by large dose administration of glucocorticoids, such as Dexamethasone (Dex) and Prednisone. GIOP may lead to fractures and even Osteonecrosis of the Femoral Head (ONFH). It has been reported that glucocorticoids inhibit osteogenesis via the suppression of osteogenic differentiation in Mesenchymal Stem Cells (MSCs), but the precise mechanism underlying this suppression awaits further investigation. Meanwhile, novel and efficacious therapies are recommended to cope with GIOP. In this study, we demonstrated that Dex had the inhibitory effect on Bone Morphogenetic Protein 9 (BMP9)-induced ALP activities and matrix mineralization in Mouse Embryonic Fibroblasts (MEFs). In addition, the study confirmed that Dex decreased the expression of osteogenic markers such as Runx2 and OPN. However, the inhibitory effect of Dex on these osteogenic markers can be reversed when combined with insulin-like growth factor 1 (IGF-1). Regarding the inhibitory mechanism, we found that the level of AKT and p-AKT can be decreased by Dex and that Ly294002, the PI3K inhibitor, can block the reversal effect of IGF-1. Moreover, the knockdown or inhibition of COX-2 produced similar results to those of Ly294002. Our findings indicated that IGF-1 may reverse the osteogenic inhibitory effect of Dex via PI3K/AKT pathway, which may be associated with the up-regulation of COX-2. This study may provide new clinical management strategy for GIOP cases.

Insulin-Like Growth Factor 1 in the Cardiovascular System

Non-communicable diseases, such as cardiovascular diseases, are the leading cause of mortality worldwide. For this reason, a tremendous effort is being made worldwide to effectively circumvent these afflictions, where insulin-like growth factor 1 (IGF1) is being proposed both as a marker and as a central cornerstone in these diseases, making it an interesting molecule to focus on. Firstly, at the initiation of metabolic deregulation by overfeeding, IGF1 is decreased/inhibited. Secondly, such deficiency seems to be intimately related to the onset of MetS and establishment of vascular derangements leading to atherosclerosis and finally playing a definitive part in cerebrovascular and myocardial accidents, where IGF1 deficiency seems to render these organs vulnerable to oxidative and apoptotic/necrotic damage. Several human cohort correlations together with basic/translational experimental data seem to confirm deep IGF1 implication, albeit with controversy, which might, in part, be given by experimental design leading to blurred result interpretation.

Cardiac examination in children with Laron syndrome undergoing mecasermin therapy

BACKGROUND

Laron syndrome (LS), which can be defined as primary growth hormone resistance or insensitivity, is a rare genetic disease inherited by an autosomal recessive trait. Although it is undistinguishable from growth hormone deficiency, LS has high levels of growth hormone, but insulin-like growth factor (IGF-1) cannot be synthesized. Mecasermin treatment is the only option for the patients who suffer from LS. This study aims to research cardiac findings of children with LS, who receive treatment with mecasermin.

METHODS

The study enrolled five children four males and one female, 4 M/1 F with LS, two of whom were siblings with a mean age of 6.3±2.1 years, a body weight of 13.36±4.74 kg, a height of 88±8.7 cm, and a body mass index (BMI) of 16.47±3.35. Their demographic data were obtained from their family and files. The children received mecasermin via subcutaneous injection at 0.04-0.12 μg/kg doses twice per day. The duration of mecasermin treatment was 8-53 months. All of them were examined clinically by electrocardiogram and echocardiogram.

RESULTS

Their cardiac examinations were normal, except for one case, who had systolic murmur at cardiac auscultation. Arrhythmia was not observed on their electrocardiograms. The echocardiograms did not show a significant congenital cardiac anomaly. Their cardiac measure and functions were within normal ranges. The echocardiogram of the child with the murmur showed mitral and tricuspid insufficiency. The Doppler images showed pulmonary hypertension findings. These findings were proven by angiography. The vasoreactivity test results of that patient were negative. No reason could be found for the observed pulmonary hypertension. We diagnosed this finding as a primary pulmonary hypertension and Bosentan therapy was started.

CONCLUSIONS

In this study, we showed that cardiac findings were consistent with previous studies. To the best of our knowledge, the observed pulmonary hypertension in children with LS, who received treatment with or without mecasermin, is reported for first time in the literature.

Randomized placebo controlled trial evaluating the safety and efficacy of single low-dose intracoronary insulin-like growth factor following percutaneous coronary intervention in acute myocardial infarction (RESUS-AMI)

BACKGROUND

Residual and significant postinfarction left ventricular (LV) dysfunction, despite technically successful percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI), remains an important clinical issue. In preclinical models, low-dose insulin-like growth factor 1 (IGF1) has potent cytoprotective and positive cardiac remodeling effects. We studied the safety and efficacy of immediate post-PCI low-dose intracoronary IGF1 infusion in STEMI patients.

METHODS

Using a double-blind, placebo-controlled, multidose study design, we randomized 47 STEMI patients with significantly reduced (≤40%) LV ejection fraction (LVEF) after successful PCI to single intracoronary infusion of placebo (n = 15), 1.5 ng IGF1 (n = 16), or 15 ng IGF1 (n = 16). All received optimal medical therapy. Safety end points were freedom from hypoglycemia, hypotension, or significant arrhythmias within 1 hour of therapy. The primary efficacy end point was LVEF, and secondary end points were LV volumes, mass, stroke volume, and infarct size at 2-month follow-up, all assessed by magnetic resonance imaging. Treatment effects were estimated by analysis of covariance adjusted for baseline (24 hours) outcome.

RESULTS

No significant differences in safety end points occurred between treatment groups out to 30 days (χ² test, P value = .77). There were no statistically significant differences in baseline (24 hours post STEMI) clinical characteristics or LVEF among groups. LVEF at 2 months, compared to baseline, increased in all groups, with no statistically significant differences related to treatment assignment. However, compared with placebo or 1.5 ng IGF1, treatment with 15 ng IGF1 was associated with a significant improvement in indexed LV end-diastolic volume (P = .018), LV mass (P = .004), and stroke volume (P = .016). Late gadolinium enhancement (±SD) at 2 months was lower in 15 ng IGF1 (34.5 ± 29.6 g) compared to placebo (49.1 ± 19.3 g) or 1.5 ng IGF1 (47.4 ± 22.4 g) treated patients, although the result was not statistically significant (P = .095).

CONCLUSIONS

In this pilot trial, low-dose IGF1, given after optimal mechanical reperfusion in STEMI, is safe but does not improve LVEF. However, there is a signal for a dose-dependent benefit on post-MI remodeling that may warrant further study.

Primary growth hormone insensitivity and psychomotor delay

We report a case of short stature irresponsive to growth hormone (GH) replacement therapy. Low GH response to provocative tests and undetectable IGF-1 levels had suggested GH deficiency, while response to therapy indicated GH insensitivity. Molecular evaluation of the GH/IGF-1 axis should be performed in these cases to improve diagnosis and therapy.

Growth hormone insensitivity: Mexican case report

Herein, we present a 14-year-old patient with short stature (134 cm) referred from Paediatrics to our department for complementary evaluation since growth hormone (GH) treatment failed to show any improvement. He was born premature and small for gestational age. Genital examination classified the patient as Tanner I-II with small penis and testicular size for his age. Biochemical analyses revealed normal GH levels with low serum insulin-like growth factor-1 (IGF-1). Molecular diagnosis confirmed several mutations in IGF1R and IGFALS, and so he was diagnosed with Laron Syndrome or GH insensibility and treated with IGF-1 substitutive therapy.

Learning points

Evaluation of the GH/IGF-1 axis when short stature does not respond to conservative treatment must be included in the ordinary practice.Laron Syndrome real incidence should be calculated once undiagnosed cases arise, as treatment, due to lack of market, is unaffordable.Even when adulthood is reached, and no longitudinal growth can be achieved, still IGF-1 treatment in Laron Syndrome patients should be pursued as metabolic and protective derangements could arise.

Insulin-like Growth Factors in a clinical setting: Review of IGF-I

BACKGROUND AND AIMS

Interest in growth hormone (GH) is inextricably linked to the need for in depth understanding of the somatomedins (insulin-like growth factors) which are polypeptides structurally similar to insulin and with broad physiological activity. To date, the most commonly known is Insulin-Like Growth Factor I (IGF-I). Despite considerable current knowledge of IGF-I, however, its bioactivity is incompletely understood. Measurement of IGF-I is of the utmost importance in the diagnosis and treatment of, for example acromegaly and growth hormone deficiency. The development of recombinant IGF-I, has allowed its use in such cases. Clinical practice, however, shows that few young/adult patients will benefit from treatment with the rIGF-I, mecasermin, given the number of adverse effects found. This review focuses on current knowledge mainly related to IGF-I and the use of its recombinant form (rIGF-I) in clinical practice. Several functions of IGI-II have been elucidated but their clinical significance is unclear.

Cloning and expression of full-length human insulin-like growth factor binding protein 3 (IGFBP3) in the Escherichia coli

Background:

The effect of the growth hormone on target cells is mediated by the insulin-like growth factor 1 (IGF-1). IGF-1 binds to the insulin-like growth factor binding proteins (IGFBPs) in blood and biological fluids. Considering the important application of IGBP3 as a drug component, in this research we cloned and expressed the full-length IGFBP3 in the pET-11a vector and BL21 (DE3) expression host.

Materials and Methods:

First the sequence encoding of IGFBP3 was designed based on the amino acid sequence of the protein and then by codon optimization, in order to ensure the maximum expression in Escherichia coli. In the next step, the synthetic DNA encoding IGFBP3 was inserted into the pUC57 vector, at the appropriate restriction sites and then subcloned in the pET-11a expression vector in the same restriction sites. The constructed vector was transformed to E. coli BL21 as an expression host and induced in the presence of IPTG for expression of the IGFBP3 protein. Protein expression was evaluated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE).

Results:

Double digestion of the new plasmid (pET-11a -IGBP3) with NdeI and BamHI showed two bands in 873 bp and 5700 bp. To study the accurate cloning procedure, the plasmid was sequenced and its authenticity was confirmed. Also the expected protein band (31.6 kDa) was observed in SDS-PAGE analysis.

Conclusion:

DNA fragment encoding the full-length IGFBP3 protein was accurately cloned in the pET-11a expression vector and the recombinant plasmid transformed to E. coli BL21 (DE3) expression host. Results of the SDS-PAGE analysis verified that recombinant IGFBP3 (31.6 kDa) are successfully expressed under the control of T7 promoter. As we shown pET-11a can be successfully used for expression of the IGFBP3 protein.

Meta-analysis of genome-wide association studies of adult height in East Asians identifies 17 novel loci

Human height is associated with risk of multiple diseases and is profoundly determined by an individual's genetic makeup and shows a high degree of ethnic heterogeneity. Large-scale genome-wide association (GWA) analyses of adult height in Europeans have identified nearly 180 genetic loci. A recent study showed high replicability of results from Europeans-based GWA studies in Asians; however, population-specific loci may exist due to distinct linkage disequilibrium patterns. We carried out a GWA meta-analysis in 93 926 individuals from East Asia. We identified 98 loci, including 17 novel and 81 previously reported loci, associated with height at P < 5 × 10(-8), together explaining 8.89% of phenotypic variance. Among the newly identified variants, 10 are commonly distributed (minor allele frequency, MAF > 5%) in Europeans, with comparable frequencies with in Asians, and 7 single-nucleotide polymorphisms are with low frequency (MAF < 5%) in Europeans. In addition, our data suggest that novel biological pathway such as the protein tyrosine phosphatase family is involved in regulation of height. The findings from this study considerably expand our knowledge of the genetic architecture of human height in Asians.

Replication study of the association of SNPs in the LHX3-QSOX2 and IGF1 loci with adult height in the Japanese population; wide-ranging comparison of each SNP genotype distribution

Adult height is a highly heritable trait involving multiple genes. Recent genome-wide association studies have identified that SNP rs12338076 in the LHX3-QSOX2 locus, and rs1457595 and rs17032362 in the IGF1 locus are associated with human height in the Japanese population (Okada et al. (2010)). We performed a replication study to examine the associations between these three SNPs and adult height in the Japanese population based on autopsy cases. However, it was not possible to confirm that all these SNPs influenced adult height in the study population. We first conducted a wide-ranging survey of these three SNPs in the above genes using nine different populations including Asians, Africans and Caucasians, and demonstrated that the genotypes of rs12338076 and rs17032362 were distributed in an ethnicity-dependent manner; even within Asian populations, the genotype distributions of the SNPs differed widely. Although there are differences in height distribution between different populations, possibly due to genetic factors and/or gene-environmental interactions, the contradictory results of the association study and ethnic differences in genotype distribution allow us to assume that these height-related SNPs in the genes may contribute to adult height to a slight extent, at least in the Japanese population. It is anticipated that the present information will be useful for developing a reliable tool for personal identification through elucidation of the genetic basis of human height.

Therapy of growth disorders

PURPOSE OF REVIEW

We review recent developments in the therapy of growth disorders, focusing mainly on recent developments in the field of growth hormone (GH) therapy.

RECENT FINDINGS

Review of current practice reveals wide variation in the approach to short stature and the institution of GH therapy. No new indications for GH treatment have been approved by the Food and Drug Administration since 2007, but off-label use has been explored in several chronic illnesses. There is also increasing focus on GH effects beyond increase in stature (e.g. effects on body composition and bone density). As the experience with GH increases, the long-term risks and outcomes are better understood and risks appear to be low. Data regarding beneficial effects of GH in Prader-Willi syndrome are accumulating but questions remain about patient selection, start age and safety. Recombinant insulin-like growth factor 1 has become more widely available and has been aggressively promoted for Food and Drug Administration-approved indications as well as off-label uses in the last few years. The use of aromatase inhibitors has been tempered by concern about side-effects and lack of efficacy.

SUMMARY

Growth hormone remains the mainstay of therapy for growth disorders, though other options, including recombinant insulin-like growth factor 1, are being investigated in various settings.

A genome-wide association study in 19 633 Japanese subjects identified LHX3-QSOX2 and IGF1 as adult height loci

Previous genome-wide association studies (GWASs) have identified several loci associated with human height; however, such evidence was mostly reported in Caucasian populations. Since the different distributions of height between populations suggest their different genetic backgrounds, analysis in different populations would be useful. Here, we present the results of a GWAS for adult height in 19 633 Japanese subjects. We found eight significantly associated loci that satisfied the genome-wide significance level (P < 5.0 x 10(-8)). Of these, the association to the LHX3-QSOX2 locus was entirely novel (rs12338076, P = 2.2 x 10(-8)). We also identified the association to the IGF1 locus (rs17032362, P = 8.1 x 10(-9)). Conditional association analysis in the IGF1 locus with rs17032362 suggested the existence of an additional independent association with height to this locus (rs1457595, P = 1.2 x 10(-5)). We observed large differences in the allele frequencies of rs17032362 and rs1457595 between Japanese (34 and 9%, respectively) and Caucasian (1.7 and 0%, respectively) populations, thereby suggesting weak statistical powers for the IGF1 locus in the previous Caucasian GWASs for height. We extensively compared our results with those of previous reports on the Caucasian and Korean populations. We were able to replicate all four loci previously reported in Koreans (EFEMP1, ZBTB38, HMGA1 and PLAG1, P < 5.0 x 10(-8)) and 15 loci identified in Caucasians (P < 0.001). The combination of the height-associated loci identified in our study and the previous GWASs demonstrated an effect size of 1.26 cm (95% confidence interval: 1.18-1.34) per 1.0 increase of the normalized Z score for height-increasing alleles, explaining 4.6% of the total variance of adult height.