ASSENT FORM 
Lymphocyte Gene Therapy for Mild Hunter Syndrome 
We are testing a new treatment for Hunter syndrome. We are asking you and your parents if you 
want to receive this new treatment because you have Hunter syndrome. We ask that you read 
this form and ask any questions you may have about it. 
People who have Hunter syndrome are missing a certain factor called an "enzyme." Because 
they are missing the enzyme, their bodies can not breakdown certain chemicals called "MPS." 
As these MPS chemicals build up in the body, they cause the bones to grow abnormally and 
cause the joints (like the elbows and knees) to become stiff. The MPS chemicals also affect the 
heart's ability to pump blood and they cause breathing difficulties. People with Hunter syndrome 
have more and more problems as they get older as more of the MPS builds up. 
In the past there has been no way to give people with Hunter syndrome the enzyme they are 
missing. However, we think that a new treatment called "gene therapy" may be able to give you 
the missing enzyme. If these gene therapy treatments work, the enzyme will be able to break 
down the MPS that is being stored in your body and may prevent some of the problems from 
getting worse. 
To have a gene therapy treatment, you would have to have an iv needle put into each of your 
arms. The needles might sting or pinch when they are first put in, but they are usually not 
uncomfortable after they are taped down to your arm. You would then lie down on a bed for 
about 3 hours while a machine removes some of the white cells from your blood. When this is 
done, your cells will be taken to a laboratory and infected with a specially designed virus. About 
a week later, your cells will be making the enzyme and will be given back to you through another 
iv needle. 
To learn if these gene therapy treatments work, we would plan to give you 12 treatments. In 
other words, you would have one treatment every month during the next year. 
To see if the treatments are working, you would have to give some blood and urine samples each 
month. You would also have some other painless medical tests, like x-rays, done every 3 
months. 
This kind of gene therapy treatment has never been used for Hunter syndrome, but has been tried 
in a few children who have other illnesses. So far, there have been no unexpected problems 
caused by this treatment. However, this is a very new kind of treatment and we do not know if 
there will be unexpected problems that show up later. 
You or your parents can call us any time if you have questions. 
Statement of Child: 
I have read this information. I have asked questions and have received answers. Doing this is 
"OK" with me. 
Signature Date 
Signature of parent/guardian 
Date 
Signature of investigator 
Date 
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Recombinant DNA Research, Volume 20 
