Genetic studies in shoulder pathology: current status of knowledge

INTRODUCTION: The shoulder is one of the most complex joints in the body. Several studies have identified a number of possible risk factors for rotator cuff pathology that include limited vascularity of the tendons, mechanical impingement of the tendon against the acromion, intrinsic degeneration and various hereditary and genetic risk factors. The identification of possible genetic associations could improve our understanding of the underlying disease process that lead to pathology. EVIDENCE ACQUISITION: This study attempted to summarize the genetic predisposition to shoulder pathology by way of a systematic search and review of candidate gene association studies and identified single nucleotide polymorphisms (SNPs). The study followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) in addition to Methodological Index for Non-Randomized Studies (MINORS). This review only included level I to III studies. EVIDENCE SYNTHESIS: Twenty-three unique articles investigated genetic involvement in etiology and pathogenesis of shoulder pathology (tendinopathy, dislocations, rotator cuff tears, shoulder pain and bursitis) were identified and reviewed. Further an analysis of MINORS was conducted. A total of 136 unique SNPs within 36 genes were identified, in addition to three genome-wide association studies across the seven pathologies of which 40 SNPs were implicated with risk. However. a notable finding was the absence of replication studies. Secondly, there was no consistent definition of pathology across the studies. Further. the current understanding of the complex pathobiology underpinning the diverse nature of these phenotypes are still developing. CONCLUSIONS: Future research directions are moving to whole-genome sequencing as a method of predicting risk of pathology.