This study will examine whether DMSA, an oral chelating agent that removes mercury and other
metals from the body, is beneficial for children with autism. DMSA is commonly used to treat
autism, although it has never been tested in a controlled study and there is no proof that it
helps children with the disorder. Support for its use is based on single-case reports of
benefits of chelation with DMSA. This study will help determine whether or not DMSA is useful
for treating autism.
Children between 4 and 10 years of age with autism spectrum disorder who weigh at least 33
pounds, who have detectable, but not toxic, levels of mercury or lead in the blood, and who
have not previously received chelation therapy may be eligible for this study.
Participants complete a medical history, behavioral and psychological assessment and physical
examination. Blood, hair, urine and stool samples are collected for testing.
Because DMSA can remove minerals the body needs, such as zinc and iron, as well as the toxic
lead and mercury, participants take a daily multivitamin supplement starting 1 month before
beginning chelation therapy and continuing for the duration of treatment. After 1 month of
the supplementation regimen, the children are assigned to receive DMSA or placebo for 12
weeks, divided into six 2-week cycles. They take the assigned drug 3 times a day on days 1, 2
and 3 of each cycle and continue the multivitamin every day.
The children are seen in the clinic immediately before and after the first, third and sixth
cycles. At each checkup, the parent or guardian answers a set of questions about the child's
autism symptoms, physical health and medication side effects. Blood, urine and stool samples
are collected for laboratory testing.
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