I have five sisters ranging in ages from 35 to 50. Three of us have developed a problem called complex regional pain syndrome. Is this a common problem among family members?

Complex regional pain syndrome (CRPS) is a common problem after trauma to an arm or leg. The injury could be as a result of surgery or bone fracture. Distal radial (wrist) fractures are the most common injury leading to CRPS, but no one knows why exactly. CRPS can occur without any known trauma or injury. Non-traumatic cases of CRPS make up about 10 per cent of all affected patients.

The patient develops wrist and hand pain, swelling, and skin color changes. The pain and swelling are accompanied by a loss of motion and function. There can even be changes in skin temperature (warm or cold) and increased hair growth on the arm compared to the other (healthy) side. In one-third of all cases, more than one extremity (arm or leg) is affected. CRPS occurs in women much more often than men (75 to 85 per cent of all cases).

The question of whether there is a genetic link with CRPS has been raised by medical researchers. Are siblings of patients with CRPS at increased risk for CRPS as well? A group of Dutch scientists who specifically study CRPS say there's no overall increased risk. But younger patients (under 50 years old) seem more likely to have siblings who also develop CRPS.

There have been case reports of families with multiple siblings who developed CRPS. Only one study has been done to look at this connection more closely. The age factor points to a possible genetic link but there can be other environmental factors since siblings usually grow up together in the same household. More study is needed before an answer to this question of genetic susceptibility among siblings can be answered.