Osteogenesis Imperfecta Type I Caused by COL1A1 Deletions

Keratin 17 and Collagen type 1 genes: Esophageal cancer molecular marker discovery and evaluation

One hundred eighty pairs of tissues of esophageal squamous cell carcinoma (ESCC) were tested by the transcriptome sequencing in order to explore etiology factors. The chi-square test and correlation analysis demonstrated that the relative expression levels of keratin 17 (KRT17) and collagen type I α1 chain (COL1A1) were significantly higher in EC with diabetes. Expression of KRT17 was correlated with blood glucose (r = 0.204, p = 0.001) and tumor size (r = -0.177, p = 0.038) in patients. COL1A1 correlated with age (r = -0.170, p = 0.029) and blood glucose levels (r = 0.190, p = 0.015). Experimental results of qRT-PCR: KRT17 and COL1A1 genes were highly expressed in ESCC (p < 0.05). When the two genes were used as a combination test, the positive detection rate of EC was 90.6%, and the ROC curve had greater power. The KRT17 and COL1A1 genes had the potential to be biomarkers for the diagnosis of ESCC.

Osteogenesis Imperfecta and Split Foot Malformation due to 7q21.2q21.3 Deletion Including COL1A2, DLX5/6 Genes: Review of the Literature

Copy number variation in loss of 7q21 is a genetic disorder characterized by split hand/foot malformation, hearing loss, developmental delay, myoclonus, dystonia, joint laxity, and psychiatric disorders. Osteogenesis imperfecta caused by whole gene deletions of COL1A2 is a very rare condition. We report a Turkish girl with ectrodactyly, joint laxity, multiple bone fractures, blue sclera, early teeth decay, mild learning disability, and depression. A copy number variant in loss of 4.8 Mb at chromosome 7 (q21.2q21.3) included the 58 genes including DLX5, DLX6, DYNC1I1, SLC25A13, SGCE, and COL1A2 . They were identified by chromosomal microarray analysis. We compared the findings in our patients with those previously reported. This case report highlights the importance of using microarray to identify the genetic etiology in patients with ectrodactyly and osteogenesis imperfecta.

Voltage-gated calcium channels in genetic epilepsies

Voltage-gated calcium channels (VGCC) are abundant in the central nervous system and serve a broad spectrum of functions, either directly in cellular excitability or indirectly to regulate Ca2+ homeostasis. Ca2+ ions act as one of the main connections in excitation-transcription coupling, muscle contraction and excitation-exocytosis coupling, including synaptic transmission. In recent years, many genes encoding VGCCs main α or additional auxiliary subunits have been associated with epilepsy. This review sums up the current state of knowledge on disease mechanisms and provides guidance on disease-specific therapies where applicable.

TMT-based quantitative proteomic analysis revealed that FBLN2 and NPR3 are involved in the early osteogenic differentiation of mesenchymal stem cells (MSCs)

The delicate equilibrium between osteoblast and adipocyte differentiation of MSCs is highly regulated. We screened for early-stage osteogenesis- or adipogenesis-based MSCs protein expression profiles using TMT-based quantitative proteomic analysis to identify novel participating molecules. Protein annotation, hierarchical clustering, functional stratification, and protein-protein association assessments were performed. Moreover, two upregulated proteins, namely, FBLN2 and NPR3, were validated to participate in the osteogenic differentiation process of MSCs. After that, we independently downregulated FBLN2 and NPR3 over seven days of osteogenic differentiation, and we performed quantitative proteomics analysis to determine how different proteins were regulated in knockdown vs. control cells. Based on gene ontology (GO) and network analyses, FBLN2 deficiency induced functional alterations associated with biological regulation and stimulus-response, whereas NPR3 deficiency induced functional alterations related to cellular and metabolic processes, and so on. These findings suggested that proteomics remains a useful method for an in-depth study of the MSCs differentiation process. This will assist in comprehensively evaluating its role in osteoporosis and provide additional approaches for identifying as-yet-unidentified effector molecules.

Copy Number Variation and Osteoporosis

PURPOSE OF REVIEW

The purpose of this review is to summarize recent findings on copy number variations and susceptibility to osteoporosis.

RECENT FINDINGS

Osteoporosis is highly influenced by genetic factors, including copy number variations (CNVs). The development and accessibility of whole genome sequencing methods has accelerated the study of CNVs and osteoporosis. Recent findings include mutations in novel genes and validation of previously known pathogenic CNVs in monogenic skeletal diseases. Identification of CNVs in genes previously associated with osteoporosis (e.g. RUNX2, COL1A2, and PLS3) has confirmed their importance in bone remodelling. This process has been associated also with the ETV1-DGKB, AGBL2, ATM, and GPR68 genes, identified by comparative genomic hybridisation microarray studies. Importantly, studies in patients with bone pathologies have associated bone disease with the long non-coding RNA LINC01260 and enhancer sequences residing in the HDAC9 gene. Further functional investigation of genetic loci harbouring CNVs associated with skeletal phenotypes will reveal their role as molecular drivers of osteoporosis.

Clinical severity prediction in children with osteogenesis imperfecta caused by COL1A1/2 defects

Osteogenesis imperfecta (OI) is a genetic disease with an estimated prevalence of 1 in 13,500 and 1 in 9700. The classification into subtypes of OI is important for prognosis and management. In this study, we established a clinical severity prediction model depending on multiple features of variants in COL1A1/2 genes.

INTRODUCTION

Ninety percent of OI cases are caused by pathogenic variants in the COL1A1/COL1A2 gene. The Sillence classification describes four OI types with variable clinical features ranging from mild symptoms to lethal and progressively deforming symptoms.

METHODS

We established a prediction model of the clinical severity of OI based on the random forest model with a training set obtained from the Human Gene Mutation Database, including 790 records of the COL1A1/COL1A2 genes. The features used in the prediction model were respectively based on variant-type features only, and the optimized features.

RESULTS

With the training set, the prediction results showed that the area under the receiver operating characteristic curve (AUC) for predicting lethal to severe OI or mild/moderate OI was 0.767 and 0.902, respectively, when using variant-type features only and optimized features for COL1A1 defects, 0.545 and 0.731, respectively, for COL1A2 defects. For the 17 patients from our hospital, prediction accuracy for the patient with the COL1A1 and COL1A2 defects was 76.5% (95% CI: 50.1-93.2%) and 88.2% (95% CI: 63.6-98.5%), respectively.

CONCLUSION

We established an OI severity prediction model depending on multiple features of the specific variants in COL1A1/2 genes, with a prediction accuracy of 76-88%. This prediction algorithm is a promising alternative that could prove to be valuable in clinical practice.

SLC38A2 provides proline to fulfil unique synthetic demands arising during osteoblast differentiation and bone formation

Cellular differentiation is associated with the acquisition of a unique protein signature which is essential to attain the ultimate cellular function and activity of the differentiated cell. This is predicted to result in unique biosynthetic demands that arise during differentiation. Using a bioinformatic approach, we discovered osteoblast differentiation is associated with increased demand for the amino acid proline. When compared to other differentiated cells, osteoblast-associated proteins including RUNX2, OSX, OCN and COL1A1 are significantly enriched in proline. Using a genetic and metabolomic approach, we demonstrate that the neutral amino acid transporter SLC38A2 acts cell autonomously to provide proline to facilitate the efficient synthesis of proline-rich osteoblast proteins. Genetic ablation of SLC38A2 in osteoblasts limits both osteoblast differentiation and bone formation in mice. Mechanistically, proline is primarily incorporated into nascent protein with little metabolism observed. Collectively, these data highlight a requirement for proline in fulfilling the unique biosynthetic requirements that arise during osteoblast differentiation and bone formation.

The Stimulating Effect of Rosmarinic Acid and Extracts from Rosemary and Lemon Balm on Collagen Type I Biosynthesis in Osteogenesis Imperfecta Type I Skin Fibroblasts

Rosemary extract (RE) and lemon balm extract (LBE) attract particular attention of pharmacists due to their high therapeutic potential. Osteogenesis imperfecta (OI) type I is a heritable disease caused by mutations in type I collagen and characterized by its reduced amount. The aim of the study was to evaluate the effect of the extracts and rosmarinic acid (RA) on collagen type I level in OI skin fibroblasts. Phytochemical analysis of RE and LBE was carried out by liquid chromatography–photodiode array detection–mass spectrometry. The expression of collagen type I at transcript and protein levels was analyzed by qPCR, ELISA, SDS-urea PAGE, and Western blot. In OI patient’s fibroblasts the exposure to the extracts (0.1–100 µg/mL) and RA (0.1–100 µM) significantly increased collagen type I and the best results were obtained with 0.1–10 µM RA and 0.1–10 µg/mL of the extracts. LBE showed a greater stimulating effect than RE, likely due to a higher RA content. Moreover, collagen type III expression and matrix metalloproteinase (MMP-1, -2, -9) activity remained unchanged or decreased. The obtained data support the clinical potential of RA-rich extracts and RA itself in modulating the quantitative defect of type I collagen in type I OI.

Crocin promotes osteogenesis differentiation of bone marrow mesenchymal stem cells

Crocin has plentiful pharmacological effects, but its role in osteogenesis differentiation of bone marrow mesenchymal stem cells (BMSCs) is unexplored. This study explored the effect of crocin on osteogenesis differentiation, in order to provide evidence for its clinical application. In cell experiments, human BMSCs (hBMSCs) were induced by osteogenesis differentiation medium or crocin. In animal experiments, steroid-induced osteonecrosis of the femoral head (SANFH) rat models was established using lipopolysaccharide (LPS) plus methylprednisolone (MPS), and then treated with crocin. The osteogenesis differentiation capacity of hBMSCs was analyzed by alkaline phosphatase (ALP) and alizarin red S staining. Histopathological changes in rat femoral head tissues were observed by hematoxylin and eosin (H&E) staining. The expression levels of RUNX2, COL1A1, OCN, and GSK-3β in hBMSCs and rat femoral head tissues were measured by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot (WB) analysis. ALP and alizarin red S staining demonstrated that LAP activity and calcium nodules were increased in hBMSCs treated with crocin. From H&E staining results, femoral head tissues of SANFH models showed typical osteonecrosis, which could be ameliorated by crocin. WB and qRT-PCR assays detected that the expression levels of RUNX2, COL1A1, and OCN in hBMSCs and femoral head tissues of models were obviously increased after crocin treatment, while GSK-3β phosphorylation was reduced. In general, the action of crocin was concentration-dependent. Crocin might be beneficial to the recovery of SANFH through accelerating osteogenesis differentiation of BMSCs, which might be a novel therapy for related diseases.

A 235 Kb deletion at 17q21.33 encompassing the COL1A1, and two additional secondary copy number variants in an infant with type I osteogenesis imperfecta: A rare case report

BACKGROUND

Osteogenesis imperfecta (OI) is a rare group of disorders characterized by increased susceptibility to fractures due to genetically determined bone fragility. About 90% of cases are due to mutations in COL1A1 (17q21.33) or COL1A2 (7q21.3) resulting in quantitative or qualitative defects in type I collagen, a key structural constituent of bone. OI due to complete COL1A1 deletion is rare.

METHODS

We present a case of OI type I in a Caucasian female referred at 10 months of age for investigation of multiple fractures associated with minimal or no known trauma, small stature, and blue sclera. Her father has four to five lifetime fractures, blue sclera, normal stature, and a 14.5 kilobase (kb) deletion of COL1A1 detected by targeted array performed at an outside institution. Microarray comparative genomic hybridization was performed on the proband and all members of the family.

RESULTS

A previously unreported 235 kb deletion at 17q21.33 encompassing COL1A1, ITGA3, PDK2, SGCA, and HILS1 was detected in the proband. Also identified in both the proband and sibling is a maternally inherited 283 kb gain at 8p21.3 encompassing CSGALNACT1 and a 163 kb loss at 10q21.3 encompassing CTNNA3. Analysis in the father revealed the same size deletion at 17q21.33 as in the proband.

CONCLUSION

Together with previously reported cases of COL1A1 deletions, this case report emphasizes the importance of a whole-genome DNA copy number assessment in patients suspected for OI, which will elucidate the presence of precise COL1A1 deletions and any pathogenic secondary copy number variations.

Finite element analysis of bone strength in osteogenesis imperfecta

As a dedicated experimentalist, John Currey praised the high potential of finite element (FE) analysis but also recognized its critical limitations. The application of the FE methodology to bone tissue is reviewed in the light of his enthusiastic and colorful statements. In the past decades, FE analysis contributed substantially to the understanding of structure-function properties in the hierarchical organization of bone and to the simulation of bone adaptation. The systematic experimental validation of FE analysis of bone strength in anatomical locations at risk of fracture led to its application in clinical studies to evaluate efficacy of antiresorptive or anabolic treatment of bone fragility. Beyond the successful analyses of healthy or osteoporotic bone, FE analysis becomes increasingly involved in the investigation of other fragility-related bone diseases. The case of osteogenesis imperfecta (OI) is exposed, the multiscale alterations of the bone tissue and the effect of treatment summarized. A few FE analyses attempting to answer open questions in OI are then reported. An original study is finally presented that explored the structural properties of the Brtl/+ murine model of OI type IV subjected to sclerostin neutralizing antibody treatment using microFE analysis. The use of identical material properties in the four-point bending FE simulations of the femora reproduced not only the experimental values but also the statistical comparisons examining the effect of disease and treatment. Further efforts are needed to build upon the extraordinary legacy of John Currey and clarify the impact of different bone diseases on the hierarchical mechanical properties of bone.

A novel transgenic murine model with persistently brittle bones simulating osteogenesis imperfecta type I

Osteogenesis imperfecta (OI) type I caused by the null allele of COL1A1 gene is in the majority in clinical OI cases. Currently, heterozygous Mov-13 mice generated by virus insertion in the first intron of col1a1 is the exclusive model to modulate OI type I, in spite of the gradually recovered bone mineral and mechanical properties. A newly designed heterozygous col1a1^±365 OI mouse was produced in the present study by partial exons knockout (exon 2-exon 5, 365 nt of mRNA) using CRISPR/Cas9 system. The deletion resulted in generally large decrease in type I collagen synthesis due to frameshift mutation and premature chain termination, closely mimicking the pathogenic mechanism in affected individuals. And the strain possessed significantly sparse mineral scaffolds, bone loss, lowered mechanical strength and broken bone metabolism by 8 and 20 weeks compared to their littermates, suggesting a sustained skeletal weakness. Notably, the remarkable down-regulation of Yes-associated protein (YAP), one of the key coactivator in Hippo signaling pathway, was first found both in the femur and adipose derived mesenchymal stem cells (ADSCs) under osteogenic differentiation of col1a1^±365 mice, which might be responsible for the reduced osteogenic potential and brittle bones. Still, further research was needed in order to illuminate the underlying mechanism.

Osteogenesis Imperfecta: New Perspectives From Clinical and Translational Research

Osteogenesis imperfecta (OI) is a monogenic bone fragility disorder that usually is caused by mutations in one of the two genes coding for collagen type I alpha chains, COL1A1 or COL1A2. Mutations in at least 18 other genes can also lead to an OI phenotype. As genetic testing is more widely used, mutations in these genes are also more frequently discovered in individuals who have a propensity for fractures, but who do not have other typical clinical characteristics of OI. Intravenous bisphosphonate therapy is still the most widely used drug treatment approach. Preclinical studies in OI mouse models have shown encouraging effects when the antiresorptive effect of a bisphosphonate was combined with bone anabolic therapy using a sclerostin antibody. Other novel experimental treatment approaches include inhibition of transforming growth factor beta signaling with a neutralizing antibody and the inhibition of myostatin and activin A by a soluble activin receptor 2B. © 2019 The Authors. JBMR Plus published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research

New Insights Into Monogenic Causes of Osteoporosis

Osteoporosis, characterized by deteriorated bone microarchitecture and low bone mineral density, is a chronic skeletal disease with high worldwide prevalence. Osteoporosis related to aging is the most common form and causes significant morbidity and mortality. Rare, monogenic forms of osteoporosis have their onset usually in childhood or young adulthood and have specific phenotypic features and clinical course depending on the underlying cause. The most common form is osteogenesis imperfecta linked to mutations in COL1A1 and COL1A2, the two genes encoding type I collagen. However, in the past years, remarkable advancements in bone research have expanded our understanding of the intricacies behind bone metabolism and identified novel molecular mechanisms contributing to skeletal health and disease. Especially high-throughput sequencing techniques have made family-based studies an efficient way to identify single genes causative of rare monogenic forms of osteoporosis and these have yielded several novel genes that encode proteins partaking in type I collagen modification or regulating bone cell function directly. New forms of monogenic osteoporosis, such as autosomal dominant osteoporosis caused by WNT1 mutations or X-linked osteoporosis due to PLS3 mutations, have revealed previously unidentified bone-regulating proteins and clarified specific roles of bone cells, expanded our understanding of possible inheritance mechanisms and paces of disease progression, and highlighted the potential of monogenic bone diseases to extend beyond the skeletal tissue. The novel gene discoveries have introduced new challenges to the classification and diagnosis of monogenic osteoporosis, but also provided promising new molecular targets for development of pharmacotherapies. In this article we give an overview of the recent discoveries in the area of monogenic forms of osteoporosis, describing the key cellular mechanisms leading to skeletal fragility, the major recent research findings and the essential challenges and avenues in future diagnostics and treatments.

Rare Copy Number Variants in Array-Based Comparative Genomic Hybridization in Early-Onset Skeletal Fragility

Early-onset osteoporosis is characterized by low bone mineral density (BMD) and fractures since childhood or young adulthood. Several monogenic forms have been identified but the contributing genes remain inadequately characterized. In search for novel variants and novel candidate loci, we screened a cohort of 70 young subjects with mild to severe skeletal fragility for rare copy-number variants (CNVs). Our study cohort included 15 subjects with primary osteoporosis before age 30 years and 55 subjects with a pathological fracture history and low or normal BMD before age 16 years. A custom-made high-resolution comparative genomic hybridization array with enriched probe density in >1,150 genes important for bone metabolism and ciliary function was used to search for CNVs. We identified altogether 14 rare CNVs. Seven intronic aberrations were classified as likely benign. Five CNVs of unknown clinical significance affected coding regions of genes not previously associated with skeletal fragility (ETV1-DGKB, AGBL2, ATM, RPS6KL1-PGF, and SCN4A). Finally, two CNVs were pathogenic and likely pathogenic, respectively: a 4 kb deletion involving exons 1-4 of COL1A2 (NM_000089.3) and a 12.5 kb duplication of exon 3 in PLS3 (NM_005032.6). Although both genes have been linked to monogenic forms of osteoporosis, COL1A2 deletions are rare and PLS3 duplications have not been described previously. Both CNVs were identified in subjects with significant osteoporosis and segregated with osteoporosis within the families. Our study expands the number of pathogenic CNVs in monogenic skeletal fragility and shows the validity of targeted CNV screening to potentially pinpoint novel candidate loci in early-onset osteoporosis.

Association of COL1A1 rs1800012 polymorphism with musculoskeletal degenerative diseases: a meta-analysis

It has been reported that the single nucleotide polymorphism (SNP) rs1800012 in COL1A1 gene might be linked to the susceptibility of musculoskeletal degenerative diseases, such as osteoarthritis (OA) and intervertebral disc degeneration (IVDD). However, the data from different studies is contradictory. Here we aimed to comprehensively summarize and clarify the relationship between the SNP and musculoskeletal degenerative diseases. Seven eligible studies including 1339 cases and 5406 controls were screened out from PubMed, Web Of Science and Cochrane library databases. Significant association was identified in sub group analysis of IVDD in homozygote model (GG versus TT: OR = 0.33, 95% CI 0.14–0.78, P = 0.012), heterozygote model (GT versus TT: OR = 0.29, 95% CI 0.11–0.72, P = 0.008) and dominant model (GG/GT versus TT: OR = 0.31, 95% CI 0.13–0.74, P = 0.008). Additionally, significant relationship was also found in sub group analysis of severe degree of IVDD in homozygote model (GG versus TT: OR = 0.37, 95% CI 0.15–0.91, P = 0.031), heterozygote model (GT versus TT: OR = 0.33, 95% CI 0.13–0.87,P = 0.024) and dominant model (GG/GT versus TT: OR = 0.36, 95% CI 0.14–0.88, P = 0.025). Although no significance was observed, there is a trend that the more G allele at COL1A1 rs1800012 site, the less possibility of IVDD and severe IVDD would happen. Our results indicate that COL1A1 rs1800012 polymorphism associates with the susceptibility of IVDD. However, this polymorphism may not be associated with OA risk.

Loss of stat3 function leads to spine malformation and immune disorder in zebrafish

STAT (Signal Transducers and Activators of Transcription) gene family members have been revealed to be involved in cell growth and differentiation in vertebrates. Despite their physiological importance, their functions are poorly studied at organ and systemic levels. In this study, we performed a genome-wide analysis using data from invertebrates to vertebrates to identify STAT genes and analyze their evolutionary history. Interestingly, the STAT gene family undergoes genome duplications during the evolutionary history with STAT3 homologues firstly appearing in the basal extant vertebrate, sea lamprey, suggesting its possible roles in spine formation. To investigate the functions of stat3 in fish species, TALEN technology was performed to generate mutant zebrafish lines. Stat3 mutant zebrafish showed no obvious defects at early developmental stage but displayed severe lateral and vertical curvature of the spine (scoliosis), spine fracture and the incomplete bone joints with narrower junction between vertebrae at early juvenile stage, as indicated by Alizarin red and Alcian blue staining, radiography and micro-computed tomography (MicroCT) analysis. Transcriptome analysis reveals dramatic alterations in a number of genes involved in immune and infection response, skeletal development and somatic growth, especially downregulated expression of collagen gene family, in the juvenile stat3 mutant zebrafish. Moreover, most of the collagen genes were detected to have abnormal expression pattern during the formation of spine deformities in stat3 mutants. Our data reveal that stat3 is specially expressed in vertebrates and required for normal spine development and immune function in zebrafish.

DNA sequence analysis in 598 individuals with a clinical diagnosis of osteogenesis imperfecta: diagnostic yield and mutation spectrum

We detected disease-causing mutations in 585 of 598 individuals (98 %) with typical features of osteogenesis imperfecta (OI). In mild OI, only collagen type I encoding genes were involved. In moderate to severe OI, mutations in 12 different genes were found; 11 % of these patients had mutations in recessive genes.

INTRODUCTION

OI is usually caused by mutations in COL1A1 or COL1A2, the genes encoding collagen type I alpha chains, but mutations in at least 16 other genes have also been associated with OI. It is presently unknown what proportion of individuals with clinical features of OI has a disease-causing mutation in one of these genes.

METHODS

DNA sequence analysis was performed on 598 individuals from 487 families who had a typical OI phenotype. OI type I was diagnosed in 43 % of individuals, and 57 % had moderate to severe OI, defined as OI types other than type I.

RESULTS

Disease-causing variants were detected in 97 % of individuals with OI type I and in 99 % of patients with moderate to severe OI. All mutations found in OI type I were dominant and exclusively affected COL1A1 or COL1A2. In moderate to severe OI, dominant mutations were found in COL1A1/COL1A2 (77 %), IFITM5 (9 %), and P4HB (0.6 %). Mutations in one of the recessive OI-associated gene were observed in 12 % of individuals with moderate to severe OI. The genes most frequently involved in recessive OI were SERPINF1 (4.0 % of individuals with moderate to severe OI) and CRTAP (2.9 %).

CONCLUSIONS

DNA sequence analysis of currently known OI-associated genes identifies disease-causing variants in almost all individuals with a typical OI phenotype. About 20 % of individuals with moderate to severe OI had mutations in genes other than COL1A1/COL1A2.

Osteogenesis imperfecta in children and adolescents-new developments in diagnosis and treatment

Osteogenesis imperfecta (OI) is the most prevalent heritable bone fragility disorder in children. It has been known for three decades that the majority of individuals with OI have mutations in COL1A1 or COL1A2, the two genes coding for collagen type I alpha chains, but in the past 10 years defects in at least 17 other genes have been linked to OI. Almost all individuals with a typical OI phenotype have a mutation in one of the currently known genes. Regarding medical treatment, intravenous bisphosphonate therapy is the most widely used medical approach. This has a marked effect on vertebra in growing children and can lead to vertebral reshaping after compression fractures, but there is little effect of bisphosphonate therapy on the development of scoliosis. Bisphosphonate treatment decreases long-bone fracture rates, but such fractures are still frequent. Newer medications with anti-resorptive and bone anabolic action are being investigated in an attempt to improve on the efficacy of bisphosphonates but the safety and efficacy of these new approaches in children with OI is not yet established.

Enhanced Wnt signaling improves bone mass and strength, but not brittleness, in the Col1a1(+/mov13) mouse model of type I Osteogenesis Imperfecta

Osteogenesis Imperfecta (OI) comprises a group of genetic skeletal fragility disorders. The mildest form of OI, Osteogenesis Imperfecta type I, is frequently caused by haploinsufficiency mutations in COL1A1, the gene encoding the α1(I) chain of type 1 collagen. Children with OI type I have a 95-fold higher fracture rate compared to unaffected children. Therapies for OI type I in the pediatric population are limited to anti-catabolic agents. In adults with osteoporosis, anabolic therapies that enhance Wnt signaling in bone improve bone mass, and ongoing clinical trials are determining if these therapies also reduce fracture risk. We performed a proof-of-principle experiment in mice to determine whether enhancing Wnt signaling in bone could benefit children with OI type I. We crossed a mouse model of OI type I (Col1a1(+/Mov13)) with a high bone mass (HBM) mouse (Lrp5(+/p.A214V)) that has increased bone strength from enhanced Wnt signaling. Offspring that inherited the OI and HBM alleles had higher bone mass and strength than mice that inherited the OI allele alone. However, OI+HBM and OI mice still had bones with lower ductility compared to wild-type mice. We conclude that enhancing Wnt signaling does not make OI bone normal, but does improve bone properties that could reduce fracture risk. Therefore, agents that enhance Wnt signaling are likely to benefit children and adults with OI type 1.