Study to Identify the Genetic Variations Associated With Phantom Limb Pain

Study to Identify the Genetic Variations Associated With Phantom Limb Pain

The purpose of this study is to determine if there is a genetic component to phantom limb pain. DNA will be analyzed for single nucleotide polymorphisms (SNPs) between the control and phantom limb pain group. Total RNA will also be isolated and profiled to asses the degree to which our gene(s) of interest are expressed in the presence or absence of phantom limb pain. Some proteins, such as inflammatory antibodies or the neurotrophin brain-derived neurotrophic factor (BDNF), will also be assessed for their association(s) with phantom limb pain.

Most patients (90-95%)with major limb amputations experience a phantom limb--the vivid impression that the limb is still present. In many cases, the sensation is painful for reasons that are currently not well understood. A small subset of amputees (<10%) never experience phantom limb pain (PLP), the painful sensation felt in the amputated limb. This difference suggests that there may be a genetic component that precludes some patients from ever experiencing PLP. Understanding the genetic components of PLP may help in predicting which patients will experience PLP and which amputees will respond to the various treatment options available.

In order to understand the genetic aspects and ultimately develop more effective treatment options in the future, patients with and without PLP will be asked to give 30 mls of blood after overnight fasting. These blood samples will be de-identified and sent to the National Institutes of Health (NIH) in Bethesda, Maryland, where all of the genetic analyses will take place.

Chronic PLP Group:

• At least 18 years of age.
• Written informed consent and written authorization for use or release of health and research study information
• Single or multiple upper and/or lower limb amputation
• At least three months post-amputation
• Ability to follow study instructions and likely to complete required visit(s)
• Experienced PLP for at least one month and at least 3 times per week
• Phantom limb pain differentiated from residual limb pain by physical exam.
• Subjects taking blood thinners or other medications that do not increase risk during a blood draw.

Non-Chronic PLP Group:

• At least 18 years of age.
• Written informed consent and written authorization for use or release of health and research study information
• Single or multiple upper and/or lower limb(s) amputation
• At least three months post-amputation
• Ability to follow study instructions and likely to complete required visit(s)
• Experienced PLP less than 10 times total and/or for less than two weeks
• Subjects taking blood thinners or other medications that do not increase risk during a blood draw.