Researchers at Massachusetts General Hospital ( MGH ) have found the first evidence of a physical abnormality underlying CRPS. They reported four CRPS patients also diagnosed with the classical or hypermobility forms of Ehlers Danlos syndrome (EDS), inherited disorders of connective tissue. They hypothesized that "EDS might contribute to the development of CRPS.
Springer Link, published an article about Japanese research "Headache and first degree family history of headache may be a risk factor for complex regional pain syndrome".
They investigated whether or not headache and family history of headache were risk factors for CRPS. Their results suggested that headache and first-degree family history were risk factors but suggested further studies with larger numbers be carried out.
It seems that pilot studies are undertaken with promising results but little follow up is undertaken. It is my thought that there appears to be a hit or miss approach to research and not enough of which is publicly funded.
Pub Med published this Netherlands study which looks at Familial occurance of complex regional pain syndrome.
They concluded that patients with familial CRPS developed it at a younger age and have a more severe characteristics suggesting a genetic predisposition.
Parc Promoting Awareness has a copy of an abstract from Stanton-Hicks, Cleveland "Complex Regional Pain Syndrome in Identical Twins". Please scroll the page in the link for this abstract. They state that this is the first reported case of CRPS with identical twins. Milly, if you read this post you'll realize how important this is. I'm giving you the link to Cleveland Clinic.
I recommend you contact them and share your information, or at least pass this suggestion and information on to your doctors.