Integrative Analysis of MicroRNA and mRNA Sequencing Data Identifies Novel Candidate Genes and Pathways for Developmental Dysplasia of Hip

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.

Early Emergent and Progressive Aberrant Subchondral Bone Remodeling Coupled with Aggravated Cartilage Degeneration in Developmental Dysplasia of the Hip

OBJECTIVE

Developmental dysplasia of the hip (DDH) is the most common skeletal development in children and could result in secondary osteoarthritis. This study aims to clarify the alternations of subchondral trabecular bone remodeling and microstructural properties during the development of DDH, and the potential influence of these alternations on the overlying cartilage degeneration and DDH progression.

DESIGN

Traditional straight-leg swaddling method was adopted to establish DDH model in newborn Sprague Dawley rats. Hip joint specimens from normal or DDH rats were used. Typical features of DDH in radiological examination were observed by x-ray analysis. Micro-computed tomography analysis was applied to evaluate the microstructural properties of subchondral bone at postnatal weeks 2, 4, and 6. Histological and immunohistochemical analyses were adopted to appraise subchondral bone remodeling activity and cartilage degeneration. The associations among subchondral bone, articular cartilage, and DDH severity were analyzed via multiple linear regression analysis.

RESULTS

Compared with control group, the subchondral bone in DDH group displayed a gradual trend of deteriorated microstructure and worsening biomechanical properties along with aberrant bone remodeling, which might be responsible for the inhibition of stress transmission from the articular cartilage to the subchondral bone and thus leading to the cartilage degeneration and accelerated DDH progression.

CONCLUSIONS

Our findings indicate that alternations of subchondral trabecular bone in a time-dependent manner could contribute to the DDH progression and the amelioration on subchondral bone might be a favorable therapeutic candidate for DDH.