Can CRPS be inherited?

DNA

There are many of their own characteristics that a parent may wish a child to inherit, but higher risk factors for developing certain medical conditions will not be among them.

Today, with the mysteries of DNA fast unravelling, there are a plethora of genetic tests available for establishing our inherited risk of developing conditions as disparate as certain types of cancer, heart conditions and neurological conditions, to name but a few.

Inherited CRPS

Sometimes it’s best to start with the conclusion – it has not yet been proven that the risk for developing CRPS can be inherited. BUT, might that change? There have been some interesting studies.

An often quoted study is one published in 2009 by researchers at the Leiden University Medical Center in the Netherlands. This study considered whether the siblings of existing CRPS patients were themselves at an increased risk of developing the condition. 405 patients and 1,242 siblings were studied.

The conclusion was that there was “no indications for an overall increased risk of developing CRPS for siblings of CRPS patients”. However, when looking specifically at those siblings under the age of 50, “the risk was significantly increased…..which may indicate that genetic factors play a more pronounced role in this subgroup.”

In another study, researchers at the Children’s Hospital in Los Angeles looking at mitochondrial DNA, found that “children meeting the CRPS-I diagnostic criteria frequently had additional autonomic-related conditions” secondary to inherited mitochondrial disease. This suggests that variants in the mitochondrial DNA sequence can predispose children towards the development of CRPS-I as well as other autonomic diseases.

CRPS and Dystonia

Dystonia is a neurological condition that results in involuntary and painful muscle spasms, jerking and abnormal postures. As many as 25% of people who develop CRPS subsequently develop Dystonia.

Whatever the evidence, circumstantial or otherwise, that genetic factors may have a role in CRPS, it seems that evidence of a link is stronger in cases of CRPS associated with Dystonia. The age at onset of CRPS in sufferers who develop Dystonia is on average 11 years younger than in other cases of CRPS. As a general rule, genetic scientists believe that early-onset forms of a disease are more likely to be genetic in origin.

The guilty gene

So with the circumstantial evidence seemingly stacking up in favour of a genetic role in at least some cases of CRPS, are there any suspects for the guilty gene or genes?

Research in South Korea based upon a blood analysis of CRPS sufferers looked at whether a gene known as MMP9 may be involved in pain progression in CRPS. It is thought that MMP9 plays an important role in neuroinflammation, wound healing and developmental processes.

This was only a small scale study and in addition, researchers could not rule out the possibility that the medication taken by those involved may have influenced the results. However, on the basis of this limited study, they concluded that the MMP9 gene may indeed have a role in pain progression in CRPS.

What is the significance of identifying the guilty gene?

Gene therapy is seen by many as the future of medicine. It remains an experimental technique whereby normal genes are transplanted into cells to replace defective or missing ones, thereby correcting genetic conditions.

Identifying a gene or genes that play a role in the development and/or progression of CRPS, potentially opens the door to new therapies to treat the condition at a cellular level.