'There are thousands of patients getting chelation at home at night in many parts of the world. And it's generally considered quite safe,' says one pediatric hematologist.

Officials said they do not know for sure what killed Abubakar Tariq Nadama, who went into cardiac arrest and died Tuesday after receiving his third chelation therapy treatment at a suburban medical clinic. State police were investigating.

The boy was undergoing the therapy at Advanced Integrative Medicine Center in Portersville, about 35 miles northwest of Pittsburgh. Neither the boy's doctor, Roy E. Kerry, nor a representative from the center returned a call for comment.

More Questions Than Answers

Chelation (pronounced key-LAY-tion) is often used in patients with sickle cell anemia, lead poisoning or other maladies. Its use dates to the 1940s.

Some people believe autism can be linked to a mercury-containing preservative once commonly used in childhood vaccines. Chelation therapy has been advocated as a remedy, although it hasn't been proven, because it causes heavy metals to leave the body through urine.

"If I were a parent considering it, I would probably stop considering it. There is no clear evidence that you can make kids better with this," said Dr. Gervasio A. Lamas, a cardiologist at Mount Sinai Medical Center-Miami Heart Institute.

Autism is a developmental disability that affects a child's social interaction and communication. There is no cure.

Because there are more questions than answers about autism, parents often desperate to help their children are willing to try anything, said Lamas, who is leading a $30 million government-funded study into chelation therapy and heart disease.

'Generally Considered Quite Safe'

Geoffrey Dubrowsky, of Brick, N.J., said his 10-year-old autistic son, Daniel, has been sleeping better and responding more to learning since starting chelation.

"These are caring parents doing whatever they can to help their child," Dubrowsky said. "We're desperate because there are no answers and the government is not willing to put up any answers."

During chelation, chemicals are administered under the skin or orally. The chemicals bind to heavy metals in the body, and patients then excrete the chemicals through urine.

One of the most common uses for chelation is lead poisoning, in which a synthetic chemical called EDTA is given to patients. It's unclear exactly how many people undergo the treatment.

"There are thousands of patients getting chelation at home at night in many parts of the world. And it's generally considered quite safe," said Dr. Lakshmanan Krishnamurti, a pediatric hematologist and director of the Sickle Cell Program at Children's Hospital of Pittsburgh.

Does Come with Risks

In 2001, the San Diego-based Autism Research Institute issued a position paper saying that 73 percent of more than 23,000 parents surveyed reported that mercury detoxification helped their children.

Lamas said the therapy does come with risks, including causing kidney damage and in some cases heart problems.

Dr. Cynthia Johnson, director of the Autism Center at the Children's Hospital of Pittsburgh, said autistic children often undergo a variety of therapies so it's difficult to pinpoint what is working and what is not.

"I tell families frankly that I don't see [chelation] as benign and it's really very scary to me," Johnson said.

The boy's mother, Marwa Nadama, said she did not blame the therapy, but was waiting for results of an autopsy.

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