A replication study for the association of rs726252 in PAPPA2 with developmental dysplasia of the hip in Chinese Han population

Genetics of hip dysplasia - a systematic literature review

BACKGROUND

Developmental dysplasia of the hip (DDH) is a congenital condition affecting 2-3% of all newborns. DDH increases the risk of osteoarthritis and is the cause of 30% of all total hip arthroplasties in adults < 40 years of age. We aim to explore the genetic background of DDH in order to improve diagnosis and personalize treatment.

METHODS

We conducted a structured literature review using PRISMA guidelines searching the Medline, Embase and Cochrane databases. We included 31 case control studies examining single nucleotide polymorphisms (SNPs) in non-syndromic DDH.

RESULTS

A total of 73 papers were included for full text review, of which 31 were single nucleotide polymorphism (SNP) case/control association studies. The literature review revealed that the majority of published papers on the genetics of DDH were mostly underpowered for detection of any significant association. One large genome wide association study has been published (N = 9,915), establishing GDF5 as a plausible risk factor.

CONCLUSIONS

DDH is known to be congenital and heritable, with family occurrence of DDH already included as a risk factor in most screening programs. Despite this, high quality genetic research is scarce and no genetic risk factors have been soundly established, prompting the need for more research.

Molecular mechanisms and genetic factors contributing to the developmental dysplasia of the hip

The most prevalent hip disease in neonates is developmental dysplasia of the hip (DDH). A timely and accurate diagnosis is required to provide the most effective treatment for pediatric patients with DDH. Heredity and gene variation have been the subject of increased attention and research worldwide as one of the factors contributing to the pathogenesis of DDH. Genome-wide association studies (GWAS), genome-wide linkage analyses (GWLA), and exome sequencing (ES) have identified variants in numerous genes and single-nucleotide polymorphisms (SNPs) as being associated with susceptibility to DDH in sporadic and DDH family patients. Furthermore, the DDH phenotype can be observed in animal models that exhibit susceptibility genes or loci, including variants in CX3CR1, KANSL1, and GDF5. The dentification of noncoding RNAs and de novo gene variants in patients with DDH-related syndrome has enhanced our understanding of the genes implicated in DDH. This article reviews the most recent molecular mechanisms and genetic factors that contribute to DDH.

Identification of KANSL1 as a novel pathogenic gene for developmental dysplasia of the hip

Developmental dysplasia of the hip (DDH) is a common anomaly leading to adult osteoarthritis. Environmental and genetic factors contribute to DDH, but its exact genetic mechanism is unclear. In this study, we used whole exome sequencing to identify the causative gene of a DDH pedigree. A rare missense variant in KANSL1 (c.C767T; p.S256F) was identified as the pathogenic cause of DDH. Subsequent mutation screening showed another missense variant in 1 of 200 sporadic patients. Kansl1-mutated mice showed reduced chondrocytes in the acetabulum and a decrease in the cartilage matrix, which may be DDH phenotype-related abnormalities. Furthermore, functional studies showed that cell proliferation was delayed and Mmp13 expression was abnormally upregulated in chondrocytes differentiated from Kansl1 mutant mouse embryonic stem cells. In conclusion, our findings suggest that KANSL1 is a novel pathogenic gene for DDH. The identification of KANSL1 variants has great diagnostic value for identifying individuals with DDH. KEY MESSAGES: Developmental dysplasia of the hip (DDH) is a common anomaly causing adult osteoarthritis. Environmental and genetic factors contribute to DDH, but its exact genetic mechanism is unclear. Using high-throughput whole exome sequencing, we found a novel variant in KANSL1 that was co-inherited by all severely affected individuals diagnosed with DDH from a three-generation family. Further analysis revealed that a Kansl1 variant in mice reduced the number of chondrocytes and decreased cartilage matrix, and mouse embryonic stem differentiation assay showed cartilage defects. These findings indicate a direct association between KANSL1 and hip development, expanding the pathogenic gene spectrum in DDH and providing insight into potential new targets for diagnosing and treating hip dysplasia.

Genetic Study of IL6, GDF5 and PAPPA2 in Association with Developmental Dysplasia of the Hip

Background: Developmental dysplasia of the hip (DDH) is one of the most prevalent skeletal disorders. DDH is considered a pathologic condition with polygenic background, but environmental and mechanic factors significantly contribute to its multifactorial etiology. Inheritance consistent with autosomal dominant type has also been observed. Single-nucleotide polymorphisms (SNPs) in various genes mostly related to formation of connective tissue are studied for a possible association with DDH. Methods: We genotyped three SNPs, rs1800796 located in the promoter region of the IL6 gene, rs143383 located in the 5′ untranslated region (UTR) of the GDF5 gene and rs726252 located in the fifth intron of the PAPPA2 gene. The study consisted of 45 subjects with DDH and 85 controls from all regions of Slovakia. Results: Association between DDH occurrence and studied genotypes affected by aforementioned polymorphisms was confirmed in the case of rs143383 in the GDF5 gene (p = 0.047), where the T allele was over-expressed in the study group. Meanwhile, in the matter of IL6 and PAPPA2, we found no association with DDH (p = 0.363 and p = 0.478, respectively). Conclusions: These results suggest that there is an association between DDH and GDF5 polymorphisms and that the T allele is more frequently presents in patients suffering from DDH.

Secreted frizzled-related protein 3 was genetically and functionally associated with developmental dysplasia of the hip

Background: Developmental dysplasia of the hip (DDH) is the most common joint disease in child orthopedics. Secreted Frizzled-Related Protein 3 (FRZB) plays an important role in joint development. however, no direct association between FRZB and DDH has been demonstrated.

Methods: Analysis of genotype distribution and allele frequency for detected single nucleotide polymorphisms (SNP) of FRZB was performed. FRZB expression was assayed in DDH joint tissues. Further experiments to identify the chondrogenic properties of FRZB were conducted. Potential upstream miRNAs for FRZB were assayed in DDH.

Results: Significant difference in genotype distribution for rs3768842 (OR=1.46, P=0.0081) and rs2242040 (OR=0.65, P=0.0067) was found. DDH joint tissues showed significantly higher FRZB expression. FRZB demonstrated chondrogenic and anti-hypertrophic properties in vitro. FRZB modulated cell adhesion pathway and cell spreading by regulating integrins expressions. Upstream miRNAs regulating FRZB expression were identified in DDH synovial fluid. Experiments indicated that downregulated miRNA-454 caused FRZB upregulation in DDH joint.

Conclusion: Dysregulated FRZB and its loci were associated with DDH. As a Wnt antagonist with chondrogenic properties, FRZB modulated cell adhesion pathway and cell spreading by regulating integrins expressions. FRZB in multiple DDH joint tissues might be mediated by the dysregulated miRNA expression profiles in the joint synovial fluid.

Genetic Predisposition to Developmental Dysplasia of the Hip

BACKGROUND

The etiopathogenesis of developmental dysplasia of the hip (DDH) has not been clarified. This systematic review evaluated current literature concerning all known chromosomes, loci, genes, and their polymorphisms that have been associated or not with the prevalence and severity of DDH.

METHODS

Following the established methodology of Meta-analysis of Observational Studies in Epidemiology guidelines, MEDLINE, EMBASE, and Cochrane Register of Controlled Trials were systematically searched from inception to January 2019.

RESULTS

Forty-five studies were finally included. The majority of genetic studies were candidate gene association studies assessing Chinese populations with moderate methodological quality. Among the most frequently studied are the first, third, 12th,17th, and 20th chromosomes. No gene was firmly associated with DDH phenotype. Studies from different populations often report conflicting results on the same single-nucleotide polymorphism (SNP). The SNP rs143384 of GDF5 gene on chromosome 20 demonstrated the most robust relationship with DDH phenotype in association studies. The highest odds of coinheritance in linkage studies have been reported for regions of chromosome 3 and 13. Five SNPs have been associated with the severity of DDH. Animal model studies validating previous human findings provided suggestive evidence of an inducing role of mutations of the GDF5, CX3CR1, and TENM3 genes in DDH etiopathogenesis.

CONCLUSION

DDH is a complex disorder with environmental and genetic causes. However, no firm correlation between genotype and DDH phenotype currently exists. Systematic genome evaluation in studies with larger sample size, better methodological quality, and assessment of DDH patients is necessary to clarify the DDH heredity. The role of next-generation sequencing techniques is promising.

Developmental dysplasia of the hip: a systematic literature review of the genes related with its occurrence

Developmental dysplasia of the hip (DDH) is one of the most prevalent congenital malformations. It has a wide spectrum of anatomical abnormalities of the hip joint and is characterized by mild or incomplete formation of the acetabulum leading to laxity of the joint capsule, secondary deformity of the proximal femur and irreducible hip dislocation. It is the leading cause of early hip osteoarthritis in young individuals.

Both genetic and environmental factors have been proposed to play an important role in the pathogenesis of DDH. A high prevalence is present in Asian, Caucasian, Mediterranean and American populations, with females being more frequently affected. We evaluated a variety of genetic studies indexed in the PubMed database.

Several susceptive genes, including WISP3, PAPPA2, HOXB9, HOXD9, GDF5, TGF Beta 1, CX3CR1, UQCC, COL1A1, TbX4 and ASPN have been identified as being associated with the development of DDH. Moreover, genetic association has also been reported between hip dysplasia and other comorbidities. Even though genetic components are a crucial part in the aetiology of DDH, several DDH susceptibility genes need further investigation.

The purpose of this review is to present current literature evidence regarding genes responsible for DDH development.

Cite this article: EFORT Open Rev 2019;4:595-601. DOI: 10.1302/2058-5241.4.190006

Abnormal expression of Pappa2 gene may indirectly affect mouse hip development through the IGF signaling pathway

INTRODUCTION

Developmental dysplasia of the hip (DDH) is a major cause of disability in children, and the genetic mechanism of this disease remains unclear. In our previous study, we found that pregnancy-associated plasma protein-A2 (PAPP-A2) was associated with DDH significantly.

OBJECTIVES

The aim of this study was to investigate the insulin-like growth factor (IGF) expression and collagen synthesis as well as cartilage proliferation-related proteins in the case of abnormal expression of Pappa2 in mice to research the relationship between PAPP-A2 and the pathological changes of DDH.

METHODS

In vivo animal experiments, the mice were directly injected with 50 µl of Cas9/PAPP-A2 sgRNA lentiviruses around the hip to downregulate the Pappa2 gene expression and injected with control lentiviruses on the other side, then to observe the expression and localization of related proteins. And in an in vitro experiment, mice fibroblasts and primary chondrocytes were cultured with insulin-like growth factor binding protein-5 (IGFBP-5) protein, PAPP-A2 protein and Cas9/PAPP-A2 sgRNA lentiviruses to detect of related proteins and mRNA expression.

RESULTS

Cartilage proliferation-related proteins demonstrated a significant decrease in the PAPP-A2 knockdown hips acetabulum and femoral head cartilage, meanwhile the IGF expression was also downregulated in the soft tissue around the acetabulum compared with the control hips. Furthermore, the role PAPP-A2 played in chondrocytes and fibroblasts was the same as in the in vivo experiments, downregulation of PAPP-A2 expression or upregulation of IGFBP-5 expression can reduce collagen synthesis and cartilage proliferation.

CONCLUSIONS

PAPP-A2 may be involved in the development of the mouse hip joint by interfering the fibrous and cartilaginous metabolism via IGF pathway-associated proteins pathway.

Trans-eQTLs identified in whole blood have limited influence on complex disease biology

Trans-eQTLs have been implicated in complex traits and common diseases, but many were initially identified on the basis of having an effect in cis, and there has been no assessment of the significance of the overlap in relation to chance expectations. Here, we investigated whether trans-expression quantitative trait loci (eQTL) associations identified in whole blood contribute to variance in complex traits by determining (1) whether genome-wide significant (GWS) single-nucleotide polymorphisms (SNPs) were enriched for trans-eQTL (including trans-only eQTL), and (2) whether the genomic regions surrounding associated trans-genes were enriched for statistical associations in the relevant GWAS. On average for a given phenotype, we identify 4.8% of GWS SNPs overlapping with trans-eQTL present in blood, and show that for the majority of these phenotypes, this observation does not exceed that expected by chance. Likewise, we observe no enrichment for genetic associations with the GWAS phenotype in the regions surrounding the linked trans-genes, with the exception of rheumatoid arthritis. Interestingly, the GWS SNPs for each phenotype were consistently more enriched for unique trans-eQTL SNPs than trans-eQTL SNP-probe pairs (p = 4 × 10^-7), with schizophrenia the only exception. This relative enrichment for trans-eQTL SNPs over trans-eQTL SNP-probe pairs implies that trait-associated trans-eQTL SNPs in whole blood are less likely to be 'master regulators' than random trans-eQTL SNPs. Taken together, these results suggest little evidence for the role of blood-based trans-eQTL in complex traits and disease, although this may reflect the finite size of currently available data sets and our findings may not hold for trans-eQTLs in more trait-relevant tissues. All software is publically available at https://github.com/IMB-Computational-Genomics-Lab/eqtlOverlapper .

Association analysis on polymorphisms in WISP3 gene and developmental dysplasia of the hip in Han Chinese population: A case-control study

Developmental dysplasia of the hip (DDH) is a common skeletal disorder whereby genetic factors play a role in etiology. Multiple genes have been reported to be associated with the occurrence of DDH. WISP3 gene was found to be a causative gene for progressive pseudorheumatoid dysplasia (PPD). Reports of WISP3 gene in association with DDH are lacking. We conducted a case-control candidate gene association study enrolling three hundred and eighty-six patients with radiology confirmed DDH and 558 healthy controls. Additional haplotype-analysis was conducted to find the significant haplotype for DDH. Five SNPs rs69306665 (upstream of WISP3), rs1022313 (WISP3), rs1230345 (WISP3), rs17073268 (WISP3) and rs10456877 (downstream of WISP3) were identified for association with DDH, showing significant difference of allele frequencies with similar odds ratio ranging from 0.71 to 0.77 (p < 0.01) between cases and controls. Two haplotypes were identified between cases and controls through haplotype analysis: AAAAA with an odds ratio of 0.76 (95% CI: 0.60-0.98, p = 0.032299) and GGCGG with an odds ratio of 1.67 (95% CI: 1.37-2.04, p = 3.67 ∗ 10^-7). The results suggested WISP3 gene was associated with DDH in Chinese Han population. GGCGG haplotype might be a biomarker for DDH.