How Does Genetics Influence Joint Health?
Genetics Influence Joint Health
In each cell of your body, genes control how your tissues work. Genes contain instructions for how to make proteins – large molecules that do many important jobs in your body, including keeping your joints healthy. Each person gets half of their genes from their mother and the other half from their father. The genes they receive are stored in chromosomes, long structures inside cells that carry DNA. The DNA is a person’s unique genetic fingerprint, and it is what gives them their physical characteristics and the chances of developing certain health conditions, such as osteoarthritis (OA).
All humans have about 46 chromosomes in each of their cells, made up of 23 pairs of chromosomes from their father and their mother. Each pair of chromosomes contains two copies of every gene. There are billions of genes in the human genome – the sequence of all of our DNA – and each gene has many different variations. These variations, also called mutations, can affect how a gene works and whether it is turned on or off. The vast majority of genetic variations don’t cause diseases and most don’t change your appearance or affect your health, but some do.
Most genes are active all the time joint health, but some genes are switched off or have changes in their activity level due to a random event, like getting hit by a car, or can be turned on or off by environmental factors, like smoking, diet and exercise. A change in the activity level of a gene is known as a mutation, and it can lead to disease.
How Does Genetics Influence Joint Health?
Some genes have more than one variation – each with a slightly different version of the gene’s instructions – and each of these variations is known as an allele. Alleles can be dominant, recessive or X-linked. One characteristic may have several alleles – such as eye colour or blood type – and people can be any of the combinations (A, B, AB or O).
Researchers are currently exploring how a person’s genes influence their risk of developing OA, but there are many other things that increase someone’s chances of developing OA, such as age, obesity and joint injuries. It is important to understand all the factors that contribute to a person developing OA, in order to reduce their risk.
Although progress has been made in understanding the contribution of hip shape to OA risk, clear relationships between bone shape and genotype are less well established for other joints such as the knee. This is likely due to other risk factors, such as sex and weight, impacting on joint shape and making it difficult to link to the relevant genotype. However, advances in the ability to combine imaging data with genomic datasets are expected to further improve this research area. This will allow researchers to better establish the relationships between joint shape and a person’s genetic predisposition to develop OA. More research will also be needed to explore how other underlying mechanisms, such as metabolic processes, can influence a person’s risk of developing OA.