Genetic association study of common variants in TGFB1 and IL-6 with developmental dysplasia of the hip in Han Chinese population

Review of susceptibility genes in developmental dysplasia of the hip: A comprehensive examination of candidate genes and pathways

Developmental dysplasia of the hip (DDH) is one of the most prevalent skeletal deformities, primarily due to the incompatibility between the acetabulum and femoral head. It includes complete dislocation, partial dislocation, instability with femoral head subluxation, and a range of imaging abnormalities that reflect inadequate acetabular formation. Known risk factors for DDH include positive family history, sex, premature birth, non-cephalic delivery, oligohydramnios, gestational diabetes mellitus, maternal hypertension, associated anomalies, swaddling clothes, intrauterine space restriction, and post-term pregnancy. Various research designs have been employed in DDH studies to identify relevant genes, including candidate gene association studies (CGAS), genome-wide association studies (GWAS), restriction fragment length polymorphism (RFLP), and whole exome sequencing (WES). To date, multiple DDH-associated genes have been identified in various populations. Despite extensive research into the epidemiology, risk factors, and genes associated with DDH, its pathogenesis remains unclear. This study provides a comprehensive summary of DDH research designs and evidence for relevant gene mutations through a PubMed search.

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.

Environmental and Genetic Risk Factors in Developmental Dysplasia of the Hip for Early Detection of the Affected Population

Diagnosis of developmental dysplasia of the hip (DDH) mostly relies on physical examination and ultrasound, and both methods are operator-dependent. Late detection can lead to complications in young adults. Current evidence supports the involvement of environmental and genetic factors, such as single nucleotide variants (SNVs). Incorporating genetic factors into diagnostic methods would be useful for implementing early detection and management of affected individuals. Our aim was to analyze environmental factors and SNVs in DDH patients. We included 287 DDH cases and 284 controls. Logistic regression demonstrated an association for sex (OR 9.85, 95% CI 5.55-17.46, p = 0.0001), family history (OR 2.4, 95% CI 1.2-4.5, p = 0.006), fetal presentation (OR 3.19, 95% CI 1.55-6.54, p = 0.002), and oligohydramnios (OR 2.74, 95%CI 1.12-6.70, p = 0.026). A model predicting the risk of DDH including these variables showed sensitivity, specificity, PPV, and NPV of 0.91, 0.53, 0.74, and 0.80 respectively. The SNV rs1800470 in TGFB1 showed an association when adjusted for covariables, OR 0.49 (95% CI 0.27-0.90), p = 0.02. When rs1800470 was included in the equation, sensitivity, specificity, PPV and NPV were 0.90, 0.61, 0.84, and 0.73, respectively. Incorporating no-operator dependent variables and SNVs in detection methods could be useful for establishing uniform clinical guidelines and optimizing health resources.

Genetically inspired organoids prevent joint degeneration and alleviate chondrocyte senescence via Col11a1-HIF1α-mediated glycolysis-OXPHOS metabolism shift

INTRODUCTION

Developmental dysplasia of hip (DDH) is a hip joint disorder leading to subsequent osteoarthritis. Previous studies suggested collagen XI alpha 1 (COL11A1) as a potential gene in hip dysplasia and chondrocyte degeneration. However, no genetic association has reported COL11A1-related cellular therapy as treatment of DDH and joint degeneration.

METHODS AND RESULTS

We report identified genetic association between COL11A1 locus and DDH with genome-wide association study (GWAS). Further exome sequencing for familial DDH patients was conducted in different populations to identify potential pathogenic Col11A1 variants for familiar DDH. Further studies demonstrated involvement of COL11A1 expression was down-regulated in femoral head cartilage of DDH patients and Col11a1-KO mice with induced DDH. Col11a1-KO mice demonstrated aggravated joint degeneration and severe OA phenotype. To explore the underlying mechanism of Col11a1 in cartilage and DDH development, we generated scRNA-seq profiles for DDH and Col11a1-KO cartilage, demonstrating disrupted chondrocyte homeostasis and cellular senescence caused by Col11a1-HIF1α-mediated glycolysis-OXPHOS shift in chondrocytes. Genetically and biologically inspired, we further fabricated an intra-articular injection therapy to preventing cartilage degeneration by generating a Col11a1-over-expressed (OE) SMSC mini-organoids. Col11a1-OE organoids demonstrated superior chondrogenesis and ameliorated cartilage degeneration in DDH mice via regulating cellular senescence by up-regulated Col11a1/HIF1α-mediated glycolysis in chondrocytes.

CONCLUSION

We reported association between COL11A1 loci and DDH with GWAS and exome sequencing. Further studies demonstrated involvement of COL11A1 in DDH patients and Col11a1-KO mice. ScRNA-seq for DDH and Col11a1-KO cartilage demonstrated disrupted chondrocyte homeostasis and cellular senescence caused by Col11a1-HIF1α-mediated glycolysis-OXPHOS shift in chondrocytes. Genetically and biologically inspired, an intra-articular injection therapy was fabricated to prevent cartilage degeneration with Col11a1-OE SMSC organoids. Col11a1-OE organoids ameliorated cartilage degeneration in DDH mice via regulating cellular senescence by up-regulated Col11a1/HIF1α-mediated glycolysis in chondrocytes.

Developmental dysplasia of the hip: A systematic review of susceptibility genes and epigenetics

BACKGROUND

Developmental dysplasia of the hip (DDH) is a complex developmental deformity whose pathogenesis and susceptibility-related genes have yet to be elucidated. This systematic review summarizes the current literature on DDH-related gene mutations, animal model experiments, and epigenetic changes in DDH.

METHODS

We performed a comprehensive search of relevant documents in the Medline, Scopus, Cochrane, and ScienceDirect databases covering the period from October 1991 to October 2021. We analyzed basic information on the included studies and summarized the DDH-related mutation sites, animal model experiments, and epigenetic changes associated with DDH.

RESULTS

A total of 63 studies were included in the analysis, of which 54 dealt with the detection of gene mutations, 7 presented details of animal experiments, and 6 were epigenetic studies. No genetic mutations were clearly related to the pathogenesis of DDH, including the most frequently studied genes on chromosomes 1, 17, and 20. Most gene-related studies were performed in Han Chinese or North American populations, and the quality of these studies was medium or low. GDF5 was examined in the greatest number of studies, and mutation sites with odds ratios > 10 were located on chromosomes 3, 9, and 13. Six mutations were found in animal experiments (i.e., CX3CR1, GDF5, PAPPA2, TENM3, UFSP2, and WISP3). Epigenetics research on DDH has focused on GDF5 promoter methylation, three microRNAs (miRNAs), and long noncoding RNAs. In addition, there was also a genetic test for miRNA and mRNA sequencing.

CONCLUSIONS

DDH is a complex joint deformity with a considerable genetic component whose early diagnosis is significant for preventing disease. At present, no genes clearly involved in the pathogenesis of DDH have been identified. Research on mutations associated with this condition is progressing in the direction of in vivo experiments in animal models to identify DDH susceptibility genes and epigenetics analyses to provide novel insights into its pathogenesis. In the future, genetic profiling may improve matters.

Whole exome sequencing of 28 families of Danish descent reveals novel candidate genes and pathways in developmental dysplasia of the hip

Developmental dysplasia of the hip (DDH) is a common condition involving instability of the hip with multifactorial etiology. Early diagnosis and treatment are critical as undetected DDH is an important cause of long-term hip complications. Better diagnostics may be achieved through genetic methods, especially for patients with positive family history. Several candidate genes have been reported but the exact molecular etiology of the disease is yet unknown. In the present study, we performed whole exome sequencing of DDH patients from 28 families with at least two affected first-degree relatives. Four genes previously not associated with DDH (METTL21B, DIS3L2, PPP6R2, and TM4SF19) were identified with the same variants shared among affected family members, in more than two families. Among known association genes, we found damaging variants in DACH1, MYH10, NOTCH2, TBX4, EVC2, OTOG, and SHC3. Mutational burden analysis across the families identified 322 candidate genes, and enriched pathways include the extracellular matrix, cytoskeleton, ion-binding, and detection of mechanical stimulus. Taken altogether, our data suggest a polygenic mode of inheritance for DDH, and we propose that an impaired transduction of the mechanical stimulus is involved in the etiopathological mechanism. Our findings refine our current understanding of candidate causal genes in DDH, and provide a foundation for downstream functional studies.

Association of rs1800795 and rs1800796 polymorphisms in interleukin-6 gene and osteoarthritis risk: evidence from a meta-analysis

Multiple studies have investigated the association of interleukin-6 (IL-6) gene polymorphisms and osteoarthritis (OA) risk, but failed to reach a consistent conclusion. Therefore, this study was designed to elucidate the association of IL-6 polymorphisms and OA by a meta-analysis approach. Literature retrieval was carried out on PubMed, EMBASE, Web of Science, CNKI, and Wanfang databases. The strength of association was appraised by odds ratios (ORs) and 95% confidence intervals (95%CIs) in five genetic models. The data were merged by using RevMan 5.3 software. Ten studies with 4944 cases and 4651 controls were analyzed. Overall, no significant association was identified between rs1800795 polymorphism and OA. Subgroup analysis by ethnicity and OA site also suggested rs1800795 polymorphism was not associated with OA. For rs1800796 polymorphism, G-allele and GG-genotype carriers appeared to have an increased risk to OA (G vs. C, OR = 1.66, 95%CI 1.30-1.96, P < 0.01; GG vs. CC, OR = 1.75, 95%CI 1.07-2.84, P = 0.03; GG vs. GC + CC, OR = 1.82, 95%CI 1.42-2.34, P < 0.01). Findings of this study indicate that the rs1800795 polymorphism is not correlated to OA susceptibility, regardless of ethnicity or OA site. However, rs1800796 polymorphism trends to be associated with susceptibility to OA.

Manipulation of Interleukin-6 (IL-6) and Transforming Growth Factor Beta-1(TGFβ-1) towards viral induced liver cancer pathogenesis

Hepatocellular carcinoma (HCC) is the most common liver malignancy. Early diagnosis of HCC has always been challenging. This study aims to assess the pathogenicity and the prevalence of IL-6 -174G/C (rs1800795) and TGFβ-1 +29C/T (rs1800470) polymorphisms in HCV-infected HCC patients. Experimental strategies are integrated with computational approaches to analyse the pathogenicity of the TGFβ-1 +29C/T and IL-6-174 G/C polymorphisms in HCV-induced HCC. AliBaba2 was used to predict the effect of IL-6-174 G/C on transcription factor binding site in IL-6 gene. Structural changes in the mutant TGFβ-1 structure were determined through project HOPE. To assess the polymorphic prevalence of IL-6 -174G/C and TGFβ-1 +29C/T genotypes in HCC and control subjects, amplification refractory mutation system PCR (ARMS-PCR) was performed on 213 HCC and 216 control samples. GraphPad Prism version 8.0 was used for the statistical analysis of the results. In-silico analysis revealed the regulatory nature of both IL-6 -174G/C and TGFβ-1 +29C/T polymorphisms. ARMS-PCR results revealed that the individuals carrying TT genotype for TGFβ-1 gene have an increased risk of developing HCC (p<0.0001, OR = 5.403, RR = 2.062) as compared to individuals with CT and CC genotype. Similarly, GC genotype carriers for IL-6 gene exhibit an increased risk of HCC susceptibility (p<0.0001, OR = 2.276, RR = 1.512) as compared to the people carrying the GG genotype. Genotype TT of TGFβ-1 gene and genotype GC of IL-6 gene are found to be associated with HCV-induced HCC. IL-6 polymorphism may alter its transcription that leads to its pathogenicity. TGFβ-1 polymorphism may alter protein structure stability.

Reduced dynamic loads due to hip dislocation induce acetabular cartilage degeneration by IL-6 and MMP3 via the STAT3/periostin/NF-κB axis

Developmental dysplasia of the hip (DDH) is characterized by anatomical abnormalities of the hip joint, ranging from mild acetabular dysplasia to hip subluxation and eventually dislocation. The mechanism underlying the cartilage degeneration of the hip joints exposed to reduced dynamic loads due to hip dislocation remains unknown. We established a rodent hip dislocation (disarticulation; DA) model of DDH (DA-DDH rats and mice) by swaddling. Expression levels of periostin (Postn) and catabolic factors, such as interleukin-6 (IL-6) and matrix metalloproteinase 3 (Mmp3), increased and those of chondrogenic markers decreased in the acetabular cartilage of the DA-DDH models. Postn induced IL-6 and Mmp3 expression in chondrocytes through integrin αVβ3, focal adhesion kinase, Src, and nuclear factor-κB (NF-κB) signaling. The microgravity environment created by a random positioning machine induced Postn expression in chondrocytes through signal transducer and activator of transcription 3 (STAT3) signaling. IL-6 stimulated Postn expression via STAT3 signaling. Furthermore, cartilage degeneration was suppressed in the acetabulum of Postn^−/− DA-DDH mice compared with that in the acetabulum of wild type DA-DDH mice. In summary, reduced dynamic loads due to hip dislocation induced acetabular cartilage degeneration via IL-6 and MMP3 through STAT3/periostin/NF-κB signaling in the rodent DA-DDH models.

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.

Genetic markers of osteoarthritis: early diagnosis in susceptible Pakistani population

Background and aim

Osteoarthritis (OA) is a multiple factorial disease with unidentified specific markers. The alternate method such as biochemical and genetic markers for the diagnosis of osteoarthritis is an undeniable need of the current era. In the present study, we aimed to investigate the association of interleukin-6 (IL-6)(IL-6-174G/C), transforming growth factor-β1 (TGF-beta1-29C/T), and calmodulin 1 gene-16C/T (CALM1-16C/T) polymorphism in clinically definite Pakistani OA patients and matching controls.

Methods

The study design was based on biochemical analysis of OA via serum hyaluronic acid (HA) enzyme-linked immunosorbent assay (ELISA) test and genetic analysis based on amplification refractory mutation system (ARMS) PCR. Statistical evaluations of allele probabilities were carried through chi-squared test. This study includes 295 subjects including 100 OA patients, 105 OA susceptible, and 90 controls.

Results

HA levels obtained were distinct for all the populations: patients with a mean value of ± 5.15, susceptible with mean value of ± 2.27, and control with mean value of ± 0.50. The prevalent genotypes in OA were GG genotype for IL-6-174G/C, CT genotypes for TGF β1-29C/T, and TT genotype for CALM1-16C/T polymorphism. A significant P value of 0.0152 is obtained as a result of the comparison among the patients and controls on the number of individuals possessing the disease-associated genotypes.

Conclusions

The positive association of GG genotype for IL-6-174G/C, TT genotype for CALM1-16C/T polymorphism in OA while high prevalence of CT TGF β1-29 C/T genotypes in susceptible population in our study group implies these polymorphisms can serve as susceptible marker to OA and genetic factors for screening OA patients in Pakistan. There might be other factors that may influence disease susceptibility. However, further investigations on larger population are required to determine the consequences of genetic variations for prediagnosis of OA.

Genetics of developmental dysplasia of the hip

In the last decade, the advances in the molecular analyses and sequencing techniques allowed researchers to study developmental dysplasia of the hip (DDH) more thoroughly. Certain chromosomes, genes, loci and polymorphisms are being associated with variable severity of this disorder. The wide range of signs and symptoms is dependent either on isolated or systemic manifestation. Phenotypes of isolated cases range from only a mild ligamental laxity, through subluxation, to a complete dislocation of the femoral head. Systemic manifestation is connected to various forms of skeletal dysplasia and other malformations characterized by significant genetic aberrations. To reveal the background of DDH heredity, multiple studies focused on large sample sizes with an emphasis on the correlation between genotype, phenotype and continuous clinical examination. Etiological risk factors that have been observed and documented in patients include genetic, environmental, and mechanical factors, which significantly contribute to the familial or nonfamilial occurrence and phenotypic variability of this disorder. Still, the multifactorial etiology and pathogenesis of DDH are not yet sufficiently clarified, explained, or understood. Formation of connective tissue, osteogenesis, chondrogenesis, and all other affected pathways and variations in the function of their individual elements contribute to the creation of the pathology in a developing human body. This review article presents an up-to-date list of known DDH associated genes, their products, and functional characteristics.

Genetic variant of COL11A2 gene is functionally associated with developmental dysplasia of the hip in Chinese Han population

OBJECTIVES

Developmental dysplasia of the hip (DDH) is a common skeletal disorder. This study was conducted to demonstrate the association between DDH and a polymorphism rs9277935 of COL11A2 gene.

RESULTS

A significant difference in genotype distribution in a recessive model (TT+GT vs. GG) between two groups (P=0.017) was demonstrated. Analysis in female patients showed significantly greater frequency of minor allele G(0.49 vs. 0.43, p=0.024) and significantly higher distribution of GG genotype (p=0.006). DDH patients were found to have significantly lower COL11A2 expression than controls. Moreover, DDH patients with rs9277935 genotype TT have a significantly increased expression of COL11A2 than those with genotype GG. COL11A2 demonstrated chondrogenic properties in vitro.

CONCLUSION

Polymorphism rs9277935 of gene COL11A2 is a functional variant regulating the expression and the chondrogenic properties of COL11A2 in DDH in Chinese Han population.

METHODS

A case-control candidate gene association study was conducted in 945 patients (350 radiologically confirmed DDH patients and 595 healthy controls). Difference of COL11A2 expression in hip joint tissue was compared between the patients and the controls. Allelic difference in Col11a2 expression by rs9277935 was assessed with luciferase activity. Chondrogenic effects of Col11a2 signaling on BMSCs were also determined in vitro.

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.

Genetic variant of WIF1 gene is functionally associated with developmental dysplasia of the hip in Han Chinese population

Developmental dysplasia of the hip (DDH) is a common skeletal disorder. Studies have demonstrated a significant role of WIF1 gene in skeletal development. The present study was conducted to reveal the association between DDH and gene WIF1. A two-stage case-control candidate gene association study was conducted in total 1573 samples (586 DDH patients and 987 healthy controls) in this study. Polymorphism rs3782499 was genotyped in all samples. Difference of WIF1 expression in hip joint tissue was compared between the patients and the controls. WIF1 expression was compared among different genotypes in DDH patients. The SNP rs3782499 was found significantly associated with DDH in the two-stage study with 585 patients and 987 controls. There was a significant difference in allele frequency (p = 4.37 * 10^-5) and genotype distribution in a recessive model (AG + GG vs. AA). DDH patients were found to have significantly higher WIF1 expression than controls. Moreover, Patients with rs3782499 genotype AA have a significantly increased expression of WIF1 than those with GG. To conclude, polymorphism rs3782499 of WIF1 gene is a functional variant regulating the expression of WIF1 in DDH in Chinese Han population, which might be a potential biomarker for the early diagnosis of DDH.

Musculoskeletal ultrasound: a useful tool for diagnosis of hip developmental dysplasia: One single-center experience

Developmental dysplasia of the hip (DDH) is one of the most common congenital abnormalities of the musculoskeletal apparatus in newborns. The aim of this study was to analyze the contribution of ultrasonography in the detection of DDH in newborns and infants, identifying the regional incidence of this pathology in the central area of Romania, emphasizing the risk factors that underlie DDH etiopathogenicity.This article represents a retrospective study of 847 newborns and infants examined in the Imagistic Department of a medical center from the central area of Romania, between January 1 and December 31, 2016. The ultrasound examinations were performed for the bilateral coxofemoral joints, using the method and technique described by Graf. For subjects born in the same medical center, data regarding mother's age, birth weights, and type of delivery (natural vs. caesarian section) were statistically analyzed.In our study group, the frequency of ultrasound diagnosis obtained from the examinations of right and left hips showed that the most frequent stage was type IA, and the rarest stage was III. The IA stage of right coxofemoral joints (87.3%) was higher than in the left coxofemoral joints (87.2%). The incidence of hip dysplasia (type III) diagnosed with ultrasound examinations in subjects from the central area of Romania was 0.2% (0.1% in both hips and 0.1% for the left coxofemoral joint).The musculoskeletal ultrasound examination is effective in early detection of hip dysplasia. The implementation of national and regional programs that promote indications, risk factors, and the screening age for DDH in both rural and urban areas could be a step forward in the early diagnosis of hip dysplasia for newborns and infants. The low incidence of DDH from our study group is not able to identify the role of advanced age of the mother, high birth weight of the newborn, or caesarean section as risk factors involved in the etiology of hip dysplasia. The implementation of national and regional programs that promote the musculoskeletal ultrasound as a screening imagistic investigation for DDH, in both rural and urban areas, could be a step forward in the early diagnosis of hip dysplasia for newborns and infants.

Genetic Influence in Developmental Dysplasia of the Hip in Saudi Arabian Children Due to GDF5 Polymorphism

Developmental dysplasia of the hip (DDH) is quite common among Saudi Arabian babies. With an objective to assess the presence of SNP rs143383 and the alleles in the GDF5 gene among patients with DDH, parents, and unaffected siblings, we undertook this case-controlled study. We collected and analyzed for a functional single nucleotide polymorphism (SNP) in the 5'-untranslated region of the GDF5 gene (rs143383), 473 blood samples, (100 patients, 200 parents, 73 siblings and 100 healthy controls. We determined the association between the patients' genotype and their fathers', mothers' and siblings' genotype through Chi-square analysis. The majority of those screened possessed the TC genotype, and 61.8% of patients and their fathers had the TT genotype. There was no association between patients' and fathers' genotype, P value < 0.332, 95% CI (0.328-0.346), and between patients' and mothers', P < 0.006, 95% CI (0.004-0.007). When considering DDH patients' and the control group's genotypes, the odds ratios of TT versus other combined (0.641 > 1) and CC versus other combined (0.474 < 1) revealed that the TT genotype has higher risk of developing DDH compared with the CC genotype. The 95 percent confidence interval of TT versus other combined and CC versus other combined is 0.932-2.891 and 0.208-1.078, respectively. For patients' and fathers' genotypes, the odds ratios of TT versus other combined (1.275 > 1) and CC versus other combined (0.815 < 1) indicate that the TT genotype has higher risk of exhibiting DDH compared to the CC genotype. For patients' and siblings' genotypes, the odds ratios of TT versus other combined (1.669) and CC versus other combined (1.048) specify that the TT genotype possesses higher risk of developing DDH compared with the CC genotype. Our study shows that there exists a relationship between GDF5 (SNP rs143383) and DDH in our population. Second, we found for the first time that the genotype TT and the T allele were overly expressed in the patients and the fathers. More studies on the confirmation of this genetic marker for DDH are called for.